Shorter Cold Streaks

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KEY CONCEPTS

• Winter’s longest cold streaks have gotten shorter since 1970 in 98% (236) of 240 U.S. locations analyzed. 

• Cold streaks shrunk by six days on average across 240 locations from 1970 to 2023.

• Shorter winter cold streaks come with consequences that extend into spring and summer.

Winter cold streaks 

Extended periods of winter cold have year-round benefits. They’re key to growing valuable fruit and nut crops, building snowpack and snow-fed water supplies, sustaining ice cover on the Great Lakes, and keeping mosquito and tick populations in check.

But these sustained periods of winter cold are getting shorter as our climate warms, according to new Climate Central analysis that looks at how the longest winter cold streaks have changed since 1970 in 240 U.S. locations. 

A winter cold streak is here defined as at least two consecutive December-February days with average temperatures below the 1991-2020 winter normal average temperature at that location (see Methodology). 

Climate normals are 30-year temperature averages that represent typical climate conditions for a given location at annual, seasonal or monthly scales. 

• See how seasonal temperature normals and precipitation normals are changing. 

Shorter streaks nationwide

Climate Central found that 98% (236) of the 240 U.S. locations analyzed have experienced shrinking winter cold streaks from 1970 to 2023. 

The longest winter cold streaks got six days shorter on average across 240 stations analyzed. 

Nearly half of the locations analyzed (45%, or 107) have seen their longest winter cold streaks shrink by at least one week since 1970.

Record locations

Locations that experienced the largest average decrease in winter’s longest cold streaks span six of the nine contiguous U.S. Climate Regions: 

Although nearly all stations have trended toward shorter winter cold streaks, one saw no trend and three saw cold streaks lengthen by two to five days since 1970: Los Angeles, Calif.; Eureka, Calif.; and Idaho Falls, Idaho.

Click here for chart data for all stations

Five year-round impacts of shorter cold streaks

Shrinking cold streaks are yet another sign of our warming climate and its effects on winter — the fastest-warming season for most of the U.S. Winter warming trends have wide-ranging consequences that extend into the spring and summer.

Extended cold periods are are key to:

1. The growth of high-value fruit and nut crops that require enough winter chill to ensure spring and summer fruit production. 

• In Fresno, Calif., a leading producer of grapes and almonds (the country’s two highest-value fruit and nut crops), winter’s longest cold streaks shrunk by 14 days. This trend has likely contributed to Fresno’s decline in the winter chill required by these and other crops. 

2. Sustaining winter ice cover on the Great Lakes, which can influence lake water levels and lake-effect snow, and has cascading impacts on cultural heritage, ecosystems, and recreation. 

3. Building and maintaining the snowpack that provides much of the nation’s water supplies for drinking, irrigation and industry — particularly in the western U.S.

4. Winter recreation and snow conditions, which contributes to many regional economies and cultures around the country, also faces risks from shorter, warmer winters.

5. Controlling populations of disease-carrying pests like mosquitoes and ticks.

LOCAL STORY ANGLES

Did climate change influence today’s temperatures? 

Climate Central’s Climate Shift Index map tool shows the influence of climate change on daily low, average, and high temperatures. The Climate Shift Index is now available in KML format. Fill out this form  to receive KML links and start creating custom maps. Sign up here to receive custom email alerts when a strong influence of climate change on temperatures in your area is detected. 

FIND EXPERTS

Submit a request to SciLine from the American Association for the Advancement of Science or to the Climate Data Concierge from Columbia University. These free services rapidly connect journalists to relevant scientific experts. 

Browse maps of climate experts and services at regional NOAA, USDA, and Department of the Interior offices.  

Explore databases such as 500 Women Scientists, BIPOC Climate and Energy Justice PhDs, and Diverse Sources to find and amplify diverse expert voices. 

Reach out to your State Climate Office or the nearest Land-Grant University to connect with scientists, educators, and extension staff in your local area. 

METHODOLOGY

Daily winter (December-February) average temperatures from 1970- 2023 were obtained from the Applied Climate Information System and used to calculate the longest winter cold streak for each annual period. The longest winter cold streak is defined as the maximum number of consecutive winter days with average temperatures below the local 1991-2020 NOAA/NCEI winter normal average temperature.

Climate Central's local analyses include 247 stations. However, for data summaries based on linear trends, only 240 stations are included due to data gaps in Bend, Ore.; Dothan, Ala.; Hattiesburg, Miss.; Hazard, Ky.; Panama City, Fla.; Terre Haute, Ind.; and Wheeling, W.Va.