There is no question that it still gets cold in a warming climate—just this past October, multiple locations across the Northern U.S. broke cold and snow records—but the winter season is less cold than it used to be a half-century ago. Furthermore, it is the fastest-warming season in 38 out of 49 states. This may sound inviting to folks that love warmer weather, but a warming winter comes with consequences.
Of 242 cities analyzed, 98% (236) had an increase in average winter temperatures from 1970, with 86% (204 of 236) of those cities warming by 2°F or more. There is also a warming trend in the number of winter days reaching above-normal temperatures. Of 242 cities, 74% (179) reported an increase of at least 7 days—one week—of above-normal winter temperatures between 1970 and 2020. Overall, winter temperatures increased the most around the Great Lakes and Northeast region, which is consistent with where the winter season is warming the fastest.
A warmer winter can have negative impacts on humans, especially economically. For instance, a warmer winter threatens winter sports, like snowboarding and skiing, because of less snow accumulation and conditions that are too warm for snowmaking. Furthermore, ice fishing, a part of the culture in some Northern tier states, faces significant lake ice cover loss in the future. According to a 2018 report on the 2015-2016 skiing and snowmobiling season, these industries generated $11 billion to the U.S. economy and supported over 190,000 jobs—often in rural areas. The winter sports industry will be negatively impacted. The severity of those impacts will be driven by the amount of greenhouse gas emissions now and in the near future.
In addition to the winter sports industry, a warmer winter can also impact fruit production. Cherry, apple, and peach trees require a minimum number of winter chill hours before they can develop fruit in the subsequent spring and summer months. The winter’s chill period is decreasing and could eventually become insufficient for fruit development in the areas where the trees are currently planted. For example, the “Peach State” of Georgia is facing peach production challenges to its iconic fruit.
Average temperatures and days above normal were calculated for each winter (December, January, February) from 1969-70 to 2019-20 using data obtained from the Applied Climate Information System. Winter days above normal are defined as the number of days where the average temperature was above the 1981-2010 NOAA/NCEI climate normal. Climate Central’s local analyses include 244 stations. However, for data summaries based on linear trends, only 242 stations are included due to large data gaps in St. Johnsbury, Vt. and Wheeling, W. Va.