Plant hardiness zones are shifting north as the U.S. warms, affecting farmers and gardeners. These zones, based on the coldest temperatures of the year, determine which plants can grow and thrive in different parts of the country.

With continued heat-trapping pollution, 90% of locations are likely to shift to warmer planting zones by the middle of the century (2036-2065). The Upper Midwest is likely to be most affected. These shifts could force growers to select plants adapted to a wider and warmer range of temperatures.

Although such shifts could expand growing ranges for high-value crops such as almonds, oranges, and kiwis, they could also expand ranges for harmful weeds and pests. For example, Kudzu, a fast-growing invasive vine, is projected to continue to expand from the Southeast into the Mid-Atlantic, Midwest, and Northeast.

Climate Central analyzed past changes in the coldest temperatures of the year in 243 U.S. locations based on weather station data.