Fruit Trees for Mason City, Albert Lea and Austin, Iowa and Minnesota

On February 2, 1996, NOAA's long-record Mason City station, in town at 1,105 feet, read −45°F. At the Mason City airport, 83 feet higher, the low that morning was −32°F. That's 13°F in one city on ground most people would call flat, and it's the first thing to know about fruit trees for Mason City, Albert Lea and Austin: on a still, clear night the cold finds every river bottom, slough and drained swamp, and ground a few dozen feet higher stays warmer.

This map covers North Iowa and southern Minnesota's Freeborn and Mower counties: Mason City, Clear Lake, Northwood, Lake Mills, Osage, St. Ansgar, Nora Springs and Rockford in Iowa, and Albert Lea, Austin, Glenville, Hollandale, Lyle and Brownsdale in Minnesota. 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 (NOAA station records since the 1995-96 winter), plus a small nudge for the ground right around you. It's a safe number to plan around, not the record and not a promise of how often it comes. The MFTC zone is that number in half zones, and 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 much warmer or colder a spot runs than Mason City on a still, clear night at bloom.

Mason City, the reference town, plans for −32°F, MFTC zone 3b, with a typical winter of −17°F. The middle of the growing ground plans for −31°F, and half of it falls between −32°F and −30°F. The warm end, −28°F to −29°F and zone 4a, is around Osage, Mitchell and Meltonville, at Burchinal southwest of Mason City, at Lyle on the state line and in the town of Clear Lake. The cold end, −33°F to −34°F, is the river bottoms and the drained swamp: Muckland near Hollandale, Mapleview just north of Austin, Fertile, Rock Falls and Portland.

Why the map looks the way it does

This is Prairie Pothole country: the Des Moines Lobe on the west side, glaciated until about 12,000 years ago and left rolling, with low ridges and small swamps now mostly drained for farmland, and the Iowan Surface around Rockford. Three rivers run southeast side by side: the Shell Rock out of Albert Lea Lake through Glenville, Northwood, Plymouth, Rock Falls and Nora Springs; the Winnebago out of Clear Lake through Mason City; and the Cedar through Austin toward Osage. From the high corner around Lake Mills, Conger and Emmons, near 1,290 feet, the land falls about 280 feet to Rockford at 1,007 feet.

That's very little relief. Nearly every town sits within 60 feet of its local floor, and most have no ground 100 feet above it, so the planning low spreads only about 4°F across nine tenths of the growing ground. Where there is a rise, it shows: the slopes around Joice plan for −29°F against −31°F on the floor, and around Bancroft −30°F against −33°F. Minnesota's fruit people say even 20 feet of drop within an orchard can make a difference, and Michigan's old orchard surveys found ridges only 25 to 30 feet above the plain nearly as frost-free as high hills. Out here, 20 or 30 feet up is your thermal belt.

The worst nights are when low spots pull away. In an ordinary winter the Mason City stations in town and at the airport run together, both averaging about −21°F for the year's coldest night. On February 2, 1996, the town station, 83 feet lower, read 13°F colder. We don't know exactly where it stood, but Mason City lies in the Winnebago valley, with limestone bluffs along the river just north of town and Willow Creek in its own narrow canyon, and that's where still air drains. It doesn't always go that way: on January 16, 2009 the airport read −31°F to the town's −28°F. Flips like that usually come when arctic air arrives on a wind, which keeps the air stirred so low ground gets no extra cold.

Austin is the cold corner. NOAA's long-record station at Austin's wastewater treatment plant, at 1,199 feet, has run a median 3°F colder on the year's coldest night than Albert Lea 3SE or Northwood, and 4°F colder than Osage. Its average yearly low, −24°F, is the coldest of the long-record stations, and its record is −42°F on January 15, 1963, a morning Albert Lea 3SE and the Mason City airport bottomed at −23°F. Austin was built partly in the Cedar floodplain, and the map's number at its airport, 31 feet higher than the plant, is −30°F against −33°F at the plant.

Water does less than you'd hope. Clear Lake covers 3,684 acres but averages only 10 to 12 feet deep and is usually frozen from late November or December into late March or April. A lake shelters its shore only while it's relatively free of ice (that's how the Wisconsin State Climatology Office puts it), so the map gives these lakes no lake belt. The town of Clear Lake plans for −29°F to Mason City's −32°F, and it sits on the highest ground in Cerro Gordo County at the head of the Winnebago, about 100 feet above Mason City, with its cold draining off down the valley. Town cores get up to 2.5°F from pavement and buildings.

Snow and wind count for more. Winter wind scours the open, plowed prairie bare in places, and the coldest mornings come over fresh snow, which cuts the air off from the ground's heat. That snow also protects roots: 4 to 10 inches insulates soil well, and Wisconsin's snowless 2024-25 winter left apple damage just below the graft union. The map runs wet ground and open hay and crop ground a bit colder too, since grass and stubble insulate the surface and that ground tends to be low and flat. And every pothole, drained or not, is a closed basin that fills with cold air up to its lowest notch before any spills out.

The spring layer follows the same drainage, only sharper, since spring frost pools usually top out 30 to 200 feet up. On a still bloom night the village of Twin Lakes, in a draw at the toe of a slope south of Albert Lea, reads 8°F colder than Mason City, the coldest of any named place; Muckland reads 7°F colder, and Armstrong and South Hollandale 6°F. The warmest readings are the slopes on Albert Lea's south edge, the village of Mitchell, Lake Mills and downtown Albert Lea and Mason City. On a windy or cloudy night the pattern flattens out.

Mason City, Clear Lake and the Winnebago valley

Mason City sits on the Winnebago, once called Lime Creek, where Willow Creek comes in, with a few smaller creeks inside the city limits. Limestone and clay sit close to the surface here, and Willow Creek has cut a narrow limestone canyon through East Park, with the Prairie School houses of Rock Crest-Rock Glen, five blocks east of downtown, along its banks. Buffalo Slough, on the northeast side along Plymouth Road, is low, wet ground. The creek cuts and the slough are where the city's cold settles, so if your lot drops toward the creek, put the tender trees up by the street.

Downtown sits at 1,135 feet, 40 feet above the floor, and plans for −32°F, zone 3b, with a typical winter of −17°F. Within 3 miles the warmest tenth of the growing ground plans for −31°F and the coldest tenth −33°F. Registry Park on the west side plans about 1°F warmer than downtown, and Mason City Junction, south of town and 80 feet above the floor, plans for −31°F and reads about even with downtown at bloom. The warmest ground nearby is the farm country to the south and southwest: Cameron at −29°F and Burchinal at −28°F, both zone 4a, though both read 3°F colder than downtown at bloom.

Downtown clears anything rated −35°F or colder: Lapins and Gold sweet cherries (the hardiest sweet cherries we've found), Siberian C peach and Superior plum. Its spring reading is the reference, so it's a fair spot for Westcot apricot. Out toward Burchinal, Contender peach (−30°F) fits; it's the only commercial peach we know of that has taken −32°F.

The town of Clear Lake, on the east shore, plans for −29°F, zone 4a, with a typical winter of −17°F, but reads 3°F colder than downtown Mason City at bloom. Ventura, on the northwest basin, plans for −30°F. The high ground around the lake is windy, so a windbreak at least as tall as the trees helps, as long as it doesn't run across the slope below them and dam the cold.

Albert Lea, the lakes and western Freeborn County

Albert Lea goes by the Land Between the Lakes: Fountain Lake, made in 1854 when George S. Ruble dammed the Shell Rock at Bridge Avenue; Albert Lea Lake, 2,600 acres and the Shell Rock's source; and Pickerel, Goose and School lakes and Lake Chapeau. Downtown sits at 1,247 feet, 30 feet above the floor, and plans for −32°F, zone 3b, with a typical winter of −20°F, reading even with Mason City at bloom. Within 3 miles the ground runs from −31°F in the warmest tenth to −34°F in the coldest.

The best ground is the slope on the south edge of town. Stoney Creek Estates, 60 feet above the floor on a 4 percent grade, plans for −31°F, and so does Rainbow Terrace, 70 feet up on a 6 percent slope, with the warmest spring reading of any named place on the map, 2°F warmer than Mason City. That's the 4 to 8 percent grade Montana State recommends, and it's where I'd put apricots and sweet cherries around Albert Lea. A few miles south, Twin Lakes plans for −32°F but reads 8°F colder than Mason City at bloom; give it apples, haskap and currants. Myre-Big Island State Park, on Albert Lea Lake, has an esker, a sinuous sand-and-gravel ridge, and a rise like that sheds water and cold air both.

Around the rest of western Freeborn County, Glenville on the Shell Rock plans for −31°F and Hayward to the east −32°F, and both read 2°F to 3°F colder than Mason City in spring. Bancroft plans for −32°F with the slopes around it at −30°F, and Conger and Emmons, near 1,290 feet, −32°F and −31°F. Armstrong plans for −32°F but reads 6°F colder at bloom, out on flat, open farm ground. If you're north toward Owatonna, the Owatonna, Faribault and Northfield map covers you.

Hollandale and the drained ground

Hollandale began as a planned vegetable colony: about 15,000 acres of county swamp, drained in 1923 and sold as 20-acre farms from 1924, many to families of Dutch descent who grew onions, potatoes, carrots and celery. Flat, low, open ground that was wet a century ago reads among the coldest on the map. Muckland, right on the floor at 1,198 feet, plans for −34°F, the coldest named place, and reads 7°F colder than Mason City at bloom. South Hollandale plans for −33°F and reads 6°F colder, and Twin Grove plans for −33°F. Plant the −50°F apples, applecrabs and plums here, with haskap and currants, use any rise you have, even 10 or 20 feet, and keep hedges and shelterbelts from closing off the low side of your trees.

Austin and the Cedar River

The Cedar runs south through the east side of Austin, joined by Turtle Creek from the west and Dobbins Creek from the east. Much of the town was built in the floodplain, and after a string of floods (the worst crest, 23.4 feet, came in 2000) the city turned low ground into parks and built a flood wall. Downtown sits at 1,206 feet, only 10 feet above the floor, and plans for −32°F, zone 3b, with a typical winter of −20°F, tied with Albert Lea for the coldest typical winter of the three main towns. It reads 2°F colder than Mason City at bloom. Within 3 miles the ground runs from −31°F to −33°F.

North of town on the valley floor, Mapleview, Ramsey and Lansing all plan for −33°F, and all read 3°F to 5°F colder than Mason City at bloom. Austin Acres, the 1930s federal housing development just west of town, plans for −31°F. The warmer winter ground is off the river: Oakland, west of town and 40 feet above the floor, at −30°F, zone 3b, and Lyle, on the Iowa line, at −29°F, zone 4a. Brownsdale, northeast of town, plans for −32°F and has the best spring reading around Austin, 2°F colder than Mason City. Austin's station has the shortest season here, a median 149 frost-free days, so put early bloomers in town or out toward Brownsdale and give the Cedar bottoms to apples, haskap and currants.

Osage, St. Ansgar and Mitchell County

Osage, the City of Maples, is the warm spot on this map. The town point, at 1,182 feet and 60 feet above the floor east of the Cedar, plans for −28°F, MFTC zone 4a, with a typical winter of −15°F, and reads 1°F colder than Mason City at bloom. Mind the river, though. Spring Park sits on the Cedar 2 miles west of town, and the Osage station, about 60 feet below the town point, read −35°F in February 1996, where the map says −31°F.

Mitchell, 50 feet above its floor, plans for −29°F, zone 4a, and reads 1°F warmer than Mason City at bloom, the best spring reading of any village here. St. Ansgar plans for −30°F, and Meltonville −29°F but 4°F colder at bloom. Mitchell County also took the April 2012 freeze: a warm late March pushed fruit into early growth, then lows in the middle to upper 20s°F from April 10 to 12 cost northeast Iowa apple orchards, including Mitchell County's, 50 to 80 percent of their crop. At −28°F, Osage clears Contender and Veteran peaches and Stella cherry. Blushingstar peach (−25°F) is worth a try on a south wall in town; it came through −25°F at our place on January 13, 2024 without damage.

Northwood, Lake Mills and Worth County

Northwood, the Worth County seat on the Shell Rock, sits 30 feet above the floor and plans for −31°F, zone 3b, with a typical winter of −18°F; it reads about even with Mason City at bloom. Its station, at 1,190 feet, had the region's coldest reading in both recent big outbreaks, −32°F on January 16, 2009 and −36°F on January 31, 2019. Kensett, Manly and Grafton plan for −30°F, all zone 4a. Fertile, on a river bottom, plans for −33°F and reads 5°F colder than Mason City at bloom, and Joice is −31°F in the village and −29°F on the rises around it. Lake Mills, up in the northwest corner at 1,289 feet, plans for −30°F, zone 3b, with a typical winter of −17°F, and reads 1°F warmer than Mason City at bloom, one of the better places here for apricots. Silver Lake, east toward Northwood on open, flat ground, reads 6°F colder in spring.

The Shell Rock bottoms: Plymouth, Rock Falls, Nora Springs and Rockford

Below Northwood the Shell Rock, named for the fossil shells in the outcrops along its banks, runs through the lowest ground on the map. Plymouth plans for −32°F; Rock Falls, right on the bottom at 1,105 feet, plans for −33°F and reads 5°F colder than Mason City at bloom; Nora Springs plans for −32°F. Rockford, at 1,003 feet where the Winnebago comes in, is −32°F in the village, while the slopes around it plan for −30°F. Two miles west, the never-plowed rocky hills of Fossil and Prairie Park rise above the Winnebago floodplain, and ground up off the floodplain like that is where trees belong. Downstream, where the Shell Rock joins the West Fork Cedar above Cedar Falls, the Waterloo and Cedar Falls map picks up.

Spring frost and bloom in North Iowa and southern Minnesota

Bloom-night frost follows the same drainage as the winter cold, and it's where site matters most; the FAO's frost protection manual calls site selection the single most important method of frost protection. Open blossoms of apple, pear, cherry, peach, apricot and plum all start dying near 28°F, so a spot 4°F colder than town can lose a crop the town keeps.

NOAA's 1991 to 2020 frost dates split the stations in two. Albert Lea 3SE, Osage and Forest City 2 NNE (just west of the map) see their median last 32°F on April 28 or 29 and their last 28°F around April 14, with 162 frost-free days. Austin and the two Mason City stations wait until May 2 or 3, with the last 28°F April 17 to April 22, and get 149 to 155 frost-free days. One spring in 10 the last 32°F comes as late as May 10 at Albert Lea 3SE and May 16 to 17 at Austin and Mason City.

Clear Lake's ice usually goes out in late March or early April, and Fountain Lake's median ice-out is April 9 in records back to 1912. The water's open well before the last frosts, but these lakes are shallow, and we found no record of them holding bloom back the way the Great Lakes do. Early warmth is the bigger danger, as 2012 showed, and in February 2026 a 60°F swing in under a week had Iowa State's Suzanne Slack warning that dehardening buds can be hurt by cold that wouldn't have harmed them a week earlier.

So put apricots, peaches and sweet cherries on the highest local ground with the warmest spring reading, and apples, haskap and bush fruit lower. Through bloom, mow under 2 inches, don't till, and water a day or two before a frost night. Frost cloth of 0.5, 0.9 and 1.5 ounces per square yard buys about 4°F, 6°F and 8°F. Only about 15 percent of apple blossoms need to set for a crop, and fully open haskap flowers take 19°F. Most fruit can lose half its blossoms with negligible effect; the frost just does your thinning.

What the weather records say

NOAA station records here go back to the 1890s. The records: −45°F at the Mason City station in town on February 2, 1996; −42°F at Austin on January 15, 1963; −37°F at Northwood and −35°F at Albert Lea 3SE, both on January 12, 1912; −35°F at Osage in 1912 and again on February 1, 1996; and −32°F at the Mason City airport on February 2, 1996.

The typical winter on our map runs −15°F at Osage, −17°F at Mason City and −20°F at Albert Lea and Austin. That's the kind of average USDA's zones are built on, and Austin is usually listed as USDA zone 4b. Our zones run about a full zone colder because we plan for the bad night: NOAA station records show the worst night in about 30 winters runs a median 13°F below a station's average winter low.

What you can grow around Mason City, Albert Lea and Austin

Every plant we sell is zoned to the coldest temperature it's actually come through. Match that to your planning low, then think about bloom. Most of these want a pollenizer nearby, and our pollination maps show which varieties pair up.

Warm ground that plans for −30°F or warmer

Osage, Mitchell, Meltonville, Burchinal, Cameron, Clear Lake, Lyle, Kensett, Manly, Grafton, Oakland and Lake Mills.

• Apples: Honeycrisp, Haralson, Zestar!®, Golden Russet, Liberty
• Pears: Bartlett, Seckel, D'Anjou
• Plums: Superior with Toka (Toka is a good pollenizer for Superior), Italian
• Cherries: Lapins, Gold and Stella sweet cherries where the spring reading is good; Evan's Bali tart cherry
• Peaches and apricots: Contender, Veteran and Siberian C peaches; Sungold and Westcot apricots on your highest spot
• Grapes and berries: Marquette and Frontenac grapes, Boyne raspberry

The middle: −30°F to −32°F

Downtown Mason City, Albert Lea and Austin, Northwood, St. Ansgar, Ventura, Glenville, Hayward, Bancroft, Brownsdale, Nora Springs, Rockford, Albert Lea's south slopes and most of the farm ground.

• Apples: Wolf River, Frostbite, Snowsweet®, Cortland, Prairie Spy; Centennial and Kerr applecrabs
• Pears: Ure, Summercrisp, Cold Snap®
• Plums: Toka, Pipestone, Underwood
• Cherries: Evan's Bali and Meteor tart cherries, Romeo and Juliet dwarf cherries; Lapins and Gold only on the higher lots
• Apricots and peaches: Westcot, Morden 604 and Debbie's Gold apricots where spring reads warm; Siberian C, the hardiest peach we think is out there (it ripens very late)
• Berries and vines: Honeyberry, Montana Black Currant, Red Lake currant, Pixwell gooseberry, Valiant grape

Contender peach (−30°F) is worth a try on the warmest lots in this band, up off the floor with snow over the roots.

Cold bottoms and drained ground: −32°F to −34°F

Muckland, South Hollandale, Twin Grove, Mapleview, Ramsey, Lansing, Fertile, Plymouth, Rock Falls, Portland and the low ground along the Cedar, Shell Rock and Winnebago. These spots also read 3°F to 7°F colder than Mason City at bloom. In the 1995-96 winter, the one that set Mason City's record, Minnesota's best apple survivors (Rescue, Dolgo, Chestnut and Centennial) came from plots that saw −50°F to −55°F.

• Apples and crabs: Kindercrisp, Norda, Wealthy; Rescue and Trailman applecrabs, Dolgo crabapple. If you only plant one tree, make it Kerr or Trailman.
• Pears and plums: Bolshaya pear; Brookgold and Brookred plums
• Cherries: Cutie Pie dwarf cherry, Nanking Cherry, and Evan's Bali, good to at least −40°F to −45°F
• Berries: Honeyberry, Golden Currant, Montana Black Currant (we've never seen winter damage on it), Aronia Berry, Success serviceberry

Roots, snow, wind and timing

Roots are the weak link on open prairie. At Ed Schultz's farm in Gallatin Gateway, Montana, Bud 118 apple rootstock has seen near −50°F with no damage, under snow, and the snow is the key part. Where wind scours, hold snow over the roots with a windbreak around 30 to 40 percent dense, which spreads it evenly, but don't run one across the low side of the orchard, where it'll dam cold air. On clay or old swamp ground, test drainage first: dig 2 feet, fill it, let it drain, refill, and under 10 hours is well drained. In zone 4 and colder we taper water from mid-August so trees harden off. Timing beats depth: after the Armistice Day freeze of November 11, 1940, Iowa's 1941 apple crop was about 15 percent of normal.

Fruit history here

In the early 1900s Iowa ranked second only to Michigan in apples, and the 1940 Armistice Day blizzard and ice storm hurt the industry. It's growing again: 498 Iowa apple farms on 1,323 acres in 2022, up from 428 farms and 943 acres five years earlier. Around here, though, the big farming venture was Hollandale's vegetables, and we found no orchard district or listed orchard inside the map.

Questions people ask

What growing zone is Mason City, Iowa?

Mason City plans for −32°F, MFTC zone 3b, with a typical winter of −17°F. That typical number is the kind of average USDA's zones are built on, which is why USDA's zones read warmer than ours; we zone for the bad night instead. Clear Lake and Burchinal plan for −29°F and −28°F, zone 4a.

What hardiness zone is Austin, MN?

Austin plans for −32°F, MFTC zone 3b, with a typical winter of −20°F. It's usually listed as USDA zone 4b, which is based on an average winter; ours is based on the bad night we plan for. Its long-record NOAA station holds a −42°F record. Albert Lea also plans for −32°F, zone 3b.

When is the last frost in Mason City, Albert Lea and Austin?

NOAA station records for 1991 to 2020 put the median last 32°F on April 28 at Albert Lea 3SE, May 2 at Austin and at the Mason City station in town, and May 3 at the Mason City airport. One spring in 10 it comes as late as May 10 at Albert Lea and May 16 to 17 at Austin and Mason City.

Why does Mason City get so cold?

On February 2, 1996, NOAA's Mason City station in town read −45°F while the airport, 83 feet higher, read −32°F. Mason City sits in the Winnebago valley with limestone bluffs and creek canyons, and on still, clear nights the cold off the farm ground drains into those low spots and pools.

Can you grow peaches and apricots around Mason City and Albert Lea?

Yes, with the right varieties in the right spot. Siberian C peach (−35°F) clears the −32°F planning low in Mason City, Albert Lea and Austin, and Contender (−30°F) fits the warmest ground, like Osage and Clear Lake. Westcot (−45°F) and Debbie's Gold (−50°F) apricots have room to spare in winter but bloom early, so put them where the spring layer reads warm, like Albert Lea's south slopes.

Where are the frost pockets around Albert Lea and Austin?

The bottoms and the drained ground. Mapleview, north of Austin, plans for −33°F and Muckland near Hollandale for −34°F, and Twin Lakes south of Albert Lea reads 8°F colder than Mason City on a still bloom night. The warmer ground sits a few dozen feet up, like Oakland west of Austin at −30°F and Albert Lea's south slopes at −31°F.

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.