Who's Dreaming of a White Christmas?
If you live in the western United States, then there is a good chance your coldest day of the year is fast approaching.
You can find out when your coldest day is likely to occur on NOAA's interactive map, Coldest Day of the Year on Average. On this map, weather stations across the United States are color-coded to show when, on average, they experience their coldest day. These dates are calculated using the average low temperature for each day from 1991–2020. You can click on individual weather stations to view the exact date of the coldest day of the year at that location.
The map clearly reveals that the coldest day normally occurs later in the season in the East than it does in the West. This is partly due to the timing of cold air moving down from snow-covered areas of Canada into the eastern U.S. In the western half of the country, the coldest day usually occurs in December. In the eastern half, it usually arrives in January or February.
Despite the west-to-east pattern of the coldest day of the year, the date of your first snowfall is influenced more by how far north you live. NOAA's First Snow Map uses historical weather data to show when you can expect the season’s first snow in your area. The map draws on historical climate records to indicate when the chance of snowfall at your location rises to at least 50%.
According to these records, much of the United States will have already experienced its first snow by now. Only if you live in California, Texas, or the Deep South are you likely still waiting for your first flakes of the year.
If you want to know your chances of enjoying a white Christmas, then you need NOAA's Probability of a White Christmas map. This map uses historical weather data to estimate the likelihood of experiencing at least one inch of snow at your location on Christmas Day. The whiter the map at your location, the greater your chances of having a white Christmas.
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