The current normal data set, which represents mean temperature, precipitation, and precipitation from 1991 to 2020, highlights that most of the country has warmed from 1981 to 2010 normals, with the exception of the north-central United States. The West is getting drier and the East is getting wetter.
“The Arctic is one of the fastest warming regions in the world and is warming at twice the global average,” according to the World Meteorological Organization.
In the northeast, a heat wave is often recognized as high temperatures measuring at least 90 degrees for three or more consecutive days.
Washington, DC, now averages 22 90-degree days in a row. In previous normals from the 1981-2010 data set, DC’s elevated temperature peaked at 89 degrees for 16 days, but never reached an average of 90 degrees.
Other cities in the northeast are also heating up. New York and Boston’s summer mean high temperatures have increased slightly, and the short-term 15-year average is still higher than the 30-year benchmark.
The window of three decades of observations is considered long enough to compensate for the variations expected from one year to the next. However, with so much extreme weather in recent years, accentuated by human-caused climate change, the short-term average was added for the first time to represent a period closer to today.
Despite rising temperatures in New York City, average snowfall has increased by nearly half a foot. Annual precipitation in New York has also increased overall.
In Atlanta, the city averages 20 highs over 90 degrees in summer, using the 15-year average against the new benchmark average.
A city with a greater change in annual temperatures is Chicago. The temperature has risen by more than a degree with the new average.
Salt Lake City’s average temperature has also increased dramatically – by 1 degree, and the 15-year average shows an even warmer average temperature to reflect more recent weather conditions.
In a city like Los Angeles, the high average temperature has actually cooled down while the lows have warmed slightly, which has decreased the daily variation in temperature. These warmer nights can make the hotter weather periods more dangerous because your body cannot cool itself as efficiently.
Most notably in Los Angeles is the decrease in precipitation. During winter, which is typically the wet time of year for Southern California, the city actually experienced a slight increase in precipitation from 1991 to 2020 compared to 1981 to 2010, but the short-term average is more than 2 inches shorter than average. new average. This shows how in recent times rainfall has decreased in the city.