Temperature is the primary measure of climate change, usually described as the warming of the planet as average temperatures trend higher. Not just average high temperatures are trending higher but average low temperatures – and that is having its own impact on natural systems and quality of life on Earth.
Importantly, lower temperatures, which usually occur at night, play a crucial role in cooling the Earth and providing relief from high daytime temperatures. Low temperatures are also seasonal, and there are economic and health impacts to milder winters. They interfere with cold weather businesses, such as those related to outdoor recreation, winter apparel, or snow removal. Fewer cold days in winter can also mean the failure of some crops and the lengthening of mosquito and tick seasons.
While average low temperatures are generally rising faster than average high temperatures, there are some anomalies, including a trend of lower temperatures in some places, even as temperatures around the world are increasingly warmer. (These are the U.S. cities with the most unusual weather this year.)
One explanation for this phenomenon is that the warming of the Arctic and its waters has changed the shape and reach of the polar vortex, a circular, low pressure pattern of cold air. The stretching and weakening of the system, and its impact on the jet stream, result in an increase in cold temperature extremes in the U.S. and northern Eurasia. America’s South and Midwest appear to be particularly vulnerable to polar vortex events.
The Texas cold wave of last February serves as an alarming example of what changed weather patterns can bring. The Texas event caused 150 deaths and more than $20 billion in damages. Millions of people lost power across the state, bringing to national attention the vulnerability of our electricity delivery systems, cumulatively referred to as “the grid.” In January of 2019, another polar vortex event brought extreme low temperatures to the upper Midwest, with temperatures reaching into the -60s.
While the rest of the country has experienced a pattern of decreasing extreme cold, there are towns in the United States that have experienced an increase in unusually cold days since 1948. (This is the coldest town in every state.)
To find the towns where the number of unusually cold weather days increased since 1948, 24/7 Wall St. reviewed the report Climate Change Indicators: High and Low Temperatures of the Environmental Protection Agency.
Perhaps surprising, most of the 23 towns on this list are in the South, with three towns each in Alabama, Florida, and North Carolina. Apart from one town in Pennsylvania and Michigan, the remaining six towns are in the West, with two in Colorado.
To identify the cities in which the number of unusually cold days increased from 1948-2020, 24/7 Wall St. reviewed the report Climate Change Indicators: High and Low Temperatures of the Environmental Protection Agency. Unusually cold days are classified as days in which the minimum temperature is within the fifth percentile temperature during the 1948–2020 period. Only cities with weather stations that have been active since 1948 were considered. Population data came from the U.S. Census Bureau.