Although nectarines are some of the least hardy trees that we grow, the varieties that we have been growing in Western Montana have shown to be all hardy to near -30F. If someone is in an area that has the potential to experience mid-winter extreme temps lower than this, then tread carefully. Take your microclimate into consideration. For instance, in the Bitterroot Valley where we have some of our operations, the Valley witnessed -40F temps in certain areas, typically the valley floor near the river where the frost settles. Meanwhile, areas slightly higher up on a bench, sometimes just 50-100 ft. in elevation above the valley floor, escaped these frosts and experienced no colder than -30F (some just as low as -26F). These are the areas in Montana where nectarine growing (and peach, sweet cherry, etc.) is much easier. Using data from a local weather station or neighbors who tracked past test winters to decide if nectarines are suitable can prevent a lot of headaches. If using data from a local weather station, collect data from multiple areas in your area and interpolate what your site would have experienced given its topography.