Fruit Trees for Door County, Sturgeon Bay and the Door Peninsula, Wisconsin

On February 3, 1996, NOAA's station inland at Stephenson, Michigan, read −45°F. In the same cold snap the Experiment Farm station north of Sturgeon Bay read −28°F and Washington Island −26°F, and in 117 years on file the Experiment Farm has never recorded colder than −29°F. The crop losses that make the news here come from timing instead: in 2012 a March warm spell near 80°F woke the trees, freezes in late March and April followed, and the county's cherry crop was forecast at about 500,000 pounds against a normal 8 to 10 million. Growing fruit trees for Door County, Sturgeon Bay and the Door Peninsula comes down to where the lakes' warmth reaches and where frost settles at bloom.

The map covers the peninsula from Brussels and Forestville north through Sturgeon Bay, Egg Harbor, Fish Creek, Ephraim and Sister Bay to Gills Rock, the Lake Michigan side from Jacksonport to Rowleys Bay, and across the bay Marinette, Wisconsin and Menominee, Michigan.

Type your address in the box on the map to get the number for your own place, and the list of what we sell that has come through it.

How to read this map

The big number is the 30-year planning low, the same number our cold hardiness calculator uses, nudged for the ground around you: a safe number to plan on, not the record and not a promise of how often it comes. The MFTC zone is that number in half zones. The typical winter is an average year's coldest night, the kind of number USDA's map is built on. The spring layer shows how many degrees warmer or colder a spot runs than Sturgeon Bay on a still, clear night at bloom.

Sturgeon Bay, our reference, plans for −23°F, MFTC zone 4b, typical winter −12°F. The middle of the map's growing ground plans for −26°F, zone 4a, and half of it falls between −27°F and −25°F. The warm end is Idlewild, on the bay shore north of Sturgeon Bay, at −20°F, the warmest of any named place, then Stevens Hill, Brussels, Rosiere and Maplewood at −22°F. The cold end is the low ground of Northern Door: Ephraim at −28°F, then Sister Bay, Rowleys Bay and Baileys Harbor at −26°F. Across the bay in Michigan, Johnson Landing, Carbondale and Hansen plan −26°F too.

Why the map looks the way it does

The Door Peninsula is a ridge of dolomite, the Niagara Escarpment, what people here call the Ledge, standing up to 260 feet above the lakes. North of Sturgeon Bay its west edge is a steep face over Green Bay, broken by bays and coves; from the crest the land slopes gently southeast to Lake Michigan, and the middle is mostly flat. Door County is about 80 percent water, and Wisconsin's State Climatology Office says Lake Michigan and Green Bay keep the peninsula warmer in winter. Over their records Washington Island's average yearly low is −11°F, the Experiment Farm's −15°F, Marinette's −16°F, and Stephenson's, inland in Michigan, −24°F. In the January 1951 cold snap Washington Island read −18°F while Stephenson read −35°F.

A lake only helps while it's open, though; the same office says lakes shelter their shores only when they're relatively free of ice. Green Bay is normally frozen by January, and the shallow, sheltered arms freeze first and thaw last: on March 11, 2025 Sawyer Harbor and Little Sturgeon Bay still held ice while the main bay had open leads. Lake Michigan, with a mean depth of 279 feet, is the bigger heat bank, and The Ridges Sanctuary's management plan says it gives that side warmer falls and winters, cooler springs and summers, and heavier lake-effect snow.

The coldest winter ground is the low ground of Northern Door. Ephraim, on Eagle Harbor and level with its local floor, plans for −28°F; around Ephraim and Sister Bay the floor within 3 miles plans −28°F and the benches −24°F to −25°F. Cold air drains off the upland and pools on the lowest ground, and much of that ground here is wet. The 1919 soil survey mapped the county's biggest peat tract, about 13 square miles, from North Bay to Baileys Harbor, and another big marsh from south of the ship canal to Clark Lake, behind beach-sand ridges. It found frost risk greater on peat than on the upland nearby. Peat runs cold because it's low, grassy and organic, and loose organic ground gives little heat back at night.

The spring layer tells a different story. On a still bloom night most shore villages read within about 3°F of Sturgeon Bay, but the flat farm country on top of the ridge reads 5°F to 8°F colder, even though Brussels sits 160 feet above Sturgeon Bay. On flat ground the cold has nowhere to go, and most of a pool's cold is made in place as the ground radiates to a clear sky. Accounts of the Wisconsin Ledge wine region say the same from the other side: on the Ledge's slopes cold air drains east into Lake Michigan instead of pooling the way it does on flat ground to the south and west. Slopes that fall toward water read warm: Stevens Hill in Sturgeon Bay reads 8°F warmer than the reference, the warmest spring reading of any named place on the map, and Egg Harbor 5°F warmer. A 1936 Michigan State bulletin found orchard ridges only 25 to 30 feet above the plain around them can be nearly as frost-free as high hills.

The stations agree: the median last 32°F comes May 4 at Marinette on the shore, May 10 at the Experiment Farm on the upland, and May 18 at Peshtigo, back from the shore. The two layers measure different things. The planning low leans on 30 winters of station records, so the upland farm country takes the Experiment Farm's mild winter number (−22°F to −24°F) even where it reads cold at bloom. Spring frost pools usually top out 30 to 200 feet up; winter's arctic pools run deeper. A little slope matters more in May than in February.

Sturgeon Bay, Stevens Hill and the ship canal

Sturgeon Bay sits at the head of a deep arm of Green Bay, where the ship canal cuts through to Lake Michigan. Downtown, at 602 feet by the water, plans for −23°F, MFTC zone 4b, typical winter −12°F; within 3 miles the floor plans −24°F, the benches −22°F and the warmest tenth of the ground −21°F. The bay freezes (ice fishing can start in the shipping channel in December), so in midwinter the city gets little from the water at its door. On a flat lot near the bay, plan around −24°F, and put your tenderest tree within a few feet of a south or west wall.

Stevens Hill, the neighborhood around Big Hill Park northeast of downtown and the city's highest ground, is the best named spot on the map for early bloomers. At 711 feet, 130 feet above its floor on a 7 percent slope, it plans for −22°F and reads 8°F warmer than Sturgeon Bay at bloom. Plant Westcot (−45°F) and Harlayne (−30°F) apricots there, Contender (−30°F) and Blushingstar (−25°F) peaches, and Lapins (−35°F) and Rainier (−30°F) sweet cherries. Idlewild, on the bay shore about 4 miles north-northwest of downtown, plans for −20°F with a typical winter of −9°F and reads even with Sturgeon Bay at bloom; Arctic Glo nectarine (−20°F) is worth a try there.

Carlsville, Valmy, Institute and the upland

North and east of the city the spine of the peninsula is farm and orchard country, 645 to 734 feet up and mostly flat. The University of Wisconsin's Peninsular Agricultural Research Station sits on it 2 miles north of town at 700 feet, and the map plans −23°F at its NOAA station. In winter this ground is mild for Door: Valmy and Institute plan for −23°F and Carlsville −24°F, all zone 4b, and around Valmy and Institute the floor and benches sit only 2°F apart. At bloom Valmy reads 7°F colder than Sturgeon Bay, Institute 6°F, and Carlsville, 90 feet above its floor but on a 0.6 percent grade, 5°F. Height without slope doesn't drain. The 1919 survey found the best cherries on the rolling, well-drained Miami loam north of Sturgeon Bay, bedrock 1 to 3 feet down. Pick the knolls and the ground that falls toward either shore.

Carlsville's orchards and wineries line Hwy 42 (Door County Fruit Connection, Door Peninsula Winery, Red Oak Winery). About 2 miles west, the Bayshore Blufflands drop 150 to 200 feet to a low terrace along Green Bay, with springs at the foot and seasonally flooded forest below. A wet, shaded terrace under a bluff is frost ground; plant up top, back from the edge. On the Lake Michigan side, Whitefish Bay plans for −23°F and reads even with Sturgeon Bay; West Jacksonport, inland at 725 feet, plans −24°F and reads 6°F colder. On the flat upland lean on Honeycrisp (−45°F), Haralson (−45°F) and Cortland (−40°F) apples and Montmorency (−30°F) and Evan's Bali (good to at least −40°F to −45°F) tart cherries.

Egg Harbor, Fish Creek and the Green Bay bluffs

Egg Harbor sits on a 12 percent slope above its harbor, 50 feet above the local floor. It plans for −25°F (zone 4a, a hair on the cold side), typical winter −13°F, and reads 5°F warmer than Sturgeon Bay at bloom; within 3 miles the floor plans −27°F and the benches −23°F. Juddville, 120 feet up, plans −24°F and reads 2°F colder at bloom. Wood Orchard, north of the village and the county's biggest apple grower, says Fuji and EverCrisp don't suit the short, cold season and irrigates because the thin soils hold little water. At Schartner's, frost in spring 2025 hit the lower limbs: a frost night's cold layer is shallow and heaviest at the bottom.

Fish Creek sits at its marina below the bluffs of Peninsula State Park, on a 5 percent slope that drains onto the harbor. The village plans for −23°F, zone 4b, typical winter −10°F, reads 1°F colder than Sturgeon Bay at bloom, and plans warmer than nearly all the ground within 3 miles, where the floor plans −27°F and the benches −24°F. Below the park's bluffs, spring-fed Weborg Marsh and a cedar swamp near Tennison Bay that holds water all year are cold, wet ground. On Egg Harbor's slopes, pick from the early bloomers: Lapins and Gold (−35°F) sweet cherries, Westcot and Sungold (−40°F) apricots, Contender peach, Luscious (−40°F) pear. On the floors around Fish Creek, stay with what's rated −30°F or colder.

Ephraim, Sister Bay, Ellison Bay and the tip

Ephraim, the Moravian village founded in 1853 on Eagle Harbor, sits at the bottom, level with its floor at 584 feet. It plans for −28°F, MFTC zone 4a, typical winter −14°F, the coldest planning low of any named place, and reads 2°F colder than Sturgeon Bay at bloom. Climb out of the harbor and the benches within 3 miles plan −24°F, 4°F warmer. Sister Bay plans for −26°F, zone 4a, typical winter −12°F, 2°F colder at bloom, floor −28°F, benches −25°F. Ellison Bay plans −24°F, zone 4b, 2°F colder at bloom, floor −27°F, benches −24°F. Seaquist Orchards, between Sister Bay and Ellison Bay, runs about 1,200 acres of tart cherries, the largest in Wisconsin.

Out at the tip, Gills Rock and Northport, the ferry points for Washington Island across Death's Door, plan for −23°F and −24°F, and both read even with Sturgeon Bay at bloom. Washington Island's station shows big water on both ends of the season: a mild average yearly low (−11°F) and the latest first fall frost (October 17, first 28°F November 4), but a later last spring frost (May 12) than Marinette or the Experiment Farm. On the low ground here plant what's rated −30°F or colder: Montmorency (2°F to spare at Ephraim), Evan's Bali, Spartan (−45°F) and Wealthy (−50°F) apples, Toka (−45°F) and Superior (−35°F) plums, and Kerr applecrab (−50°F). Save the sweet cherries and pears for the benches.

Baileys Harbor, Jacksonport and the Lake Michigan shore

Baileys Harbor plans for −26°F, MFTC zone 4a, typical winter −13°F, and reads 2°F colder than Sturgeon Bay at bloom; within 3 miles the floor plans −26°F and the benches −23°F. It sits at the south end of the North Bay peat tract (North Bay itself plans −25°F, zone 4a). The Ridges Sanctuary, on the north side of the village, is 1,600 acres of 30 crescent beach ridges with wet swales between them, holding the only known boreal forest in eastern Wisconsin, kept there by cold, humid air off the lake; its plan puts it about 10°F cooler than inland. Kangaroo Lake, averaging 6 feet deep and ringed by marsh, freezes early and stops helping. Rowleys Bay plans −26°F and reads even with Sturgeon Bay at bloom. Skip the swales and marsh edges for the ridges and slopes above them.

Jacksonport, home of the one-day Cherry Fest, is the warm end of this shore: −23°F, zone 4b, typical winter −11°F, 1°F colder than Sturgeon Bay at bloom, and warmer than nearly all the ground within 3 miles, where the floor plans −26°F. Summer surface water on Lake Michigan's Wisconsin shore often runs 5°F to 10°F colder than on the Michigan shore, so this side gives less summer heat: put late apples and grapes on your sunniest ground. At Jacksonport and Whitefish Bay the −25°F list opens up, including Blushingstar peach and Hardired nectarine (−25°F); around Baileys Harbor and North Bay, stay at −30°F or colder.

Southern Door: Brussels, Forestville and Little Sturgeon

Southern Door, which takes in the old Belgian settlement district around Brussels and Namur, is open farm country on heavy, lake-laid soils with red clay subsoil, poorly drained where level; the 1919 survey noted trees on level land with heavy subsoil grew poorly or died. It's high and mild in winter: Brussels, at 762 feet, plans for −22°F, zone 4b, typical winter −11°F; Rosiere, at 814 feet on the map's south edge, and Maplewood plan −22°F, Kolberg −23°F, Kodan −24°F. At bloom it holds several of the coldest spring readings of the named places: Kolberg reads 8°F colder than Sturgeon Bay, Rosiere and Kodan 7°F, Brussels and Maplewood 6°F. Forestville, down on the Ahnapee River below the dam, plans for −25°F, zone 4a, typical winter −14°F, colder than the crossroads around it (a river bottom is still a bottom), and reads 5°F colder at bloom; Cherry Lane Orchards is here.

The better ground has fall to it. Carnot, on an 8 percent toe slope, plans for −23°F and reads 4°F colder at bloom; Vignes, a bench 100 feet up, plans −23°F and Salona, 80 feet up on a 4 percent slope, −24°F, and both read only 2°F colder. Little Sturgeon, on a 6 percent slope over Little Sturgeon Bay, plans −23°F and reads even with Sturgeon Bay, though the floor within 3 miles plans −26°F. On the flats, plant apples, tart cherries and bush fruit: Honeycrisp, Haralson, Zestar!® (−40°F) and Wolf River (−45°F) apples, Meteor (−40°F) tart cherry, honeyberry (−50°F), Red Lake currant (−40°F). Save peaches, apricots and pears for the slopes. Closer to the city of Green Bay, the Green Bay, Appleton and Fox Valley map covers you.

Marinette, Menominee and the west shore of the bay

Marinette, Wisconsin sits on the south bank of the Menominee River at its mouth, with Menekaunee (East Marinette) on its east side; Menominee, Michigan, faces the bay from the north bank. Marinette plans for −24°F, zone 4b, typical winter −12°F, 2°F colder than Sturgeon Bay at bloom; Menominee and Menekaunee plan −23°F. Around both towns the floor plans −25°F and the coldest tenth −27°F. Marinette's station has 102 years on file and a record of −30°F (January 17, 1982 and February 3, 1996). Its own 30-year number is −25°F, while the map, blending it with its neighbors, plans −24°F there, so on low ground near the river, plan for −25°F.

Up the Michigan shore, Ingallston plans −25°F and Johnson Landing −26°F. Back from the water it's the Southern Door pattern again: Eagles Nest and Birch Creek plan a mild −23°F and −24°F but read 5°F and 7°F colder at bloom, Hansen reads 8°F colder, the coldest spring reading of any named place, and Carbondale has the coldest typical winter of any named place, −15°F. Farther up the Menominee River, around Iron Mountain, the Iron Mountain and Kingsford map covers you.

Spring frost and cherry bloom

Door cherries usually bloom mid to late May, full bloom lasts about two weeks, and apples peak about a week later; in a warm spring cherries can start in mid-April. NOAA station records, 1991 to 2020 medians:

• Marinette: last 32°F May 4, last 28°F April 18, late year (1 in 10) May 21; 158 frost-free days.
• Forestville, 4 miles east of town: May 9, April 24, May 22; 159 days.
• Experiment Farm: May 10, April 24, May 22; 157 days.
• Washington Island: May 12, April 27, May 29; 158 days.
• Peshtigo: May 18, May 7, May 28; 137 days.

Open blossoms of nearly every tree fruit start dying near 28°F (Michigan State's fruit people), and in a normal year Door's last 28°F comes weeks before cherry bloom: cold water holds bud break back until the hard frosts are past. Early springs break that. In 2012 a wind freeze in late March hit buds the warmth had already woken, and repeated April freezes cut the crop each time. A wind freeze is one site can't fix: with cold air pouring in on a wind there's no inversion, higher ground can be colder, and the spring layer's warm slopes aren't warm. In 2021 a five-day April stretch brought lows in the high teens, more frost came in May, and Soren's Valhalla Orchards in Sturgeon Bay lost 20 to 30 percent of its sweet cherries. In 2025 spring cold hurt some Northeast Wisconsin orchards and cut bee activity. Thaws do damage too. In one winter the AP covered (the story doesn't give the year), a January thaw to about 40°F swelled tart cherry buds, a plunge to −10°F killed them, and with drought on top Wisconsin expected about 200,000 pounds of tart cherries against 10.4 million the year before. Timing beats depth: Michigan tart cherry buds that died at about −12°F in November survived about −20°F in January.

The FAO's frost protection manual calls site the single most important method of frost protection. Put apricots, peaches, sweet cherries and plums on slopes that fall toward water, never on the flat farm country or the peat; put apples, haskap and bush fruit on the colder ground. Apples need only about 15 percent of their blossoms to set a crop, and haskap flowers take 19°F wide open. Through bloom, mow short, don't till, and water a day or two before a frost night. We haven't found a source documenting wind machines or sprinklers in Door orchards; site has been the defense here. The research station posts fruit reports in season for Southern, Central and Northern Door. Fall is the lakes' strong suit: the median first 28°F comes October 27 at Marinette and November 4 on Washington Island.

What the weather records say

NOAA station records: the Experiment Farm bottomed out at −29°F on February 10, 1912, and matched it in 1917, 1933 and the January 1982 cold snap; Marinette −30°F (January 17, 1982 and February 3, 1996); Washington Island −27°F (January 17, 1982); Peshtigo −28°F (2014 and 2019). The newer stations near Ephraim and Forestville bottomed at −22°F. The order isn't fixed: in the March 1, 1962 snap Washington Island read −26°F to Marinette's −20°F, and in the January 31, 2019 cold snap every station around here landed between −19°F and −22°F. The county averages 58.7 inches of snow a year. Winter lows have warmed 5°F to 6°F since 1950, but our window, since the 1995-96 winter, already holds February 1996 and January 2019.

USDA's 2023 map puts Sturgeon Bay's ZIP code in zones 5b and 6a, up from 5a and 5b in 2012. Our planning low puts Sturgeon Bay in MFTC zone 4b, and Door's colder low ground in 4a: USDA uses the average winter, we use the bad night. Sturgeon Bay's typical winter, −12°F, sits in USDA's 5b range.

What you can grow here

All but about 1 percent of the growing ground here plans for −28°F or warmer, so everything we sell rated −30°F or colder has come through a colder night than the map plans for nearly anywhere. Bloom, thaws and season length decide the rest.

The shore, Sturgeon Bay and slopes facing the water: −20°F to −25°F

Sturgeon Bay, Stevens Hill, Idlewild, Little Sturgeon, Fish Creek, Egg Harbor's slopes, Jacksonport, Gills Rock and Menominee, about even with Sturgeon Bay at bloom or warmer. The ground for early bloomers: Lapins and Rainier sweet cherries, Contender and Blushingstar peaches, Westcot and Harlayne apricots, Bartlett (−35°F) and D'Anjou (−30°F) pears, Italian plum (−35°F), Hardired nectarine.

The flat farm country on the ridge: −22°F to −26°F, 4°F to 8°F colder at bloom

Brussels, Rosiere, Kolberg, Kodan, Forestville, Valmy, Institute, Carlsville, Peninsula Center, West Jacksonport, and Hansen and Birch Creek on the Michigan side. Apples first: Honeycrisp, Haralson, Cortland, Spartan, Zestar!®, Wolf River and Snowsweet® (−45°F). Montmorency, Evan's Bali and Meteor tart cherries on rolling ground. Honeyberry, Red Lake and Montana Black Currant (−50°F), Pixwell gooseberry (−40°F), Boyne raspberry (−40°F). Early bloomers only on a knoll or a slope that drains.

Northern Door's low ground: −25°F to −28°F

Ephraim's shore, Sister Bay, Baileys Harbor, North Bay, Rowleys Bay, the floors around Fish Creek and Ellison Bay. Plant what's rated −30°F or colder: Montmorency, Evan's Bali, Honeycrisp, Spartan, Wealthy, Kerr, Toka and Superior plums, Siberian C peach (−35°F, the hardiest peach we think is out there; it ripens very late, so give it your sunniest slope), and Lapins, Gold and Luscious on the benches. Grapes: Marquette (−35°F) and Valiant (−50°F) in warm, sheltered spots.

UW Extension lists Montmorency and Meteor as self-fruitful and names Kaga and Toka as pollenizers for Superior plum (see our pollination maps); net tart cherries against birds. The thin soil over dolomite holds little water, so use drip, and taper it from mid-August so trees harden off. UW Extension recommends M.26, M.7 and Bud.9 for apples and warns M.9 and M.26 are very susceptible to fire blight. Roots are the weak link (Wisconsin's snowless 2024-25 winter left damage just below the graft union), and UW says the Door peninsula can carry slightly less hardy cultivars only in protected spots with reliable snow cover. Plant on a gentle slope, 4 to 8 percent, off the flat, the peat and the windy crest, and gap any hedge or cedar thicket across its low end. Fuji and Granny Smith need about 180 days from bloom and won't ripen here. Plan for cherry leaf spot, brown rot, spotted wing drosophila and apple scab.

Fruit history here

Joseph Zettel, a Swiss immigrant, planted Door's first fruit trees north of Sturgeon Bay (accounts give 1858 or 1862) and showed 20 varieties at the 1893 Chicago World's Fair. In 1891 A.L. Hatch and UW professor E.S. Goff bought 80 acres and tried plums, strawberries, raspberries and cherries; cherries did best, and by 1896 they'd settled on Montmorency. Planting often meant dynamiting the rock. The Seaquists, Swedish settlers near Ephraim, planted their first commercial orchard in 1911, and the university bought the farm north of Sturgeon Bay in 1922 that became the research station. "Cherryland" peaked around midcentury at up to 50 million pounds, and Dale Seaquist ran the county's first trunk shaker in 1972. Door's Montmorency is now about 95 percent of Wisconsin's tart cherry crop.

Questions people ask

What hardiness zone is Sturgeon Bay?

USDA's 2023 map puts ZIP code 54235 in zones 5b and 6a. We plan Sturgeon Bay for −23°F, MFTC zone 4b, with a typical winter of −12°F. USDA's zone is based on an average winter, ours on the bad night we plan for; the Experiment Farm north of town read −28°F in February 1996.

When is the last frost in Sturgeon Bay?

NOAA station records for 1991 to 2020 put the median last 32°F at May 10 at the Experiment Farm north of town, the last 28°F around April 24, and a late year (1 in 10) out to May 22. Wisconsin's State Climatology Office gives a county-wide average of May 5.

When do Door County cherry trees bloom?

Usually mid to late May, with apples about a week behind. Early springs are the risk: in 2012 freezes after a warm March cut the county's crop forecast to about 500,000 pounds against a normal 8 to 10 million.

Can you grow sweet cherries in Door County?

Yes. Lapins and Gold have come through −35°F and Rainier −30°F, and the coldest ground here plans for about −28°F. Bloom is the risk (frosts in 2021 cost Soren's Valhalla Orchards 20 to 30 percent of its sweet cherries), so plant them on a slope facing the water, like Stevens Hill.

Can you grow peaches in Door County?

Yes. Contender (−30°F) and Siberian C (−35°F) clear the planning low across nearly all of the map, and Blushingstar (−25°F) fits Sturgeon Bay, Jacksonport, Fish Creek and the other spots that plan −25°F or warmer. Peaches bloom early, so give them your best slope.

Where are the frost pockets in Door County?

At bloom, the flat farm country back from the water: Kolberg and Hansen read 8°F colder than Sturgeon Bay on a still night, Rosiere, Kodan and Valmy 7°F colder. In winter, Northern Door's low ground: Ephraim's shore plans for −28°F. The 1919 soil survey flagged the peat flats from North Bay to Baileys Harbor and from the ship canal to Clark Lake as frostier than the upland.

Warmer spots, colder spots

Here's the number to plan for at named places on the map, warmest first. Each one is the 1-in-30-year low for that spot: the cold hardiness calculator's number from the same weather stations, sharpened by our microclimate model for the ground right there. Zone is our MFTC zone, set by that one bad night, not by an average.

The weather stations behind it

These are the long-record stations in and around this map, with each one's own numbers since the winter of 1995-96. The last column is this map's 30-year number right at the station, which won't match the station exactly: it's a blend of the stations around it, the way the calculator works everywhere.

Source: NOAA records through ACIS, winters 1995-96 through 2025-26. What the "carried forward," "gaps filled" and AWOS rows mean is explained in how our microclimate maps work.