Washington's last spring freeze is coming earlier, and so are the 70s.
Climate change is ending winter sooner than it used to, jump-starting spring and the planting season.
Despite recent warmth that caused an outburst of early flowers and a brief blast of tree pollen, there’s still some time before our last freeze and the onset of planting season.
But long-term trends show winter ending progressively earlier and a lengthening growing season. In other words, it may not be long before gardeners can begin their work.
Throughout the Washington region, the date of the last freeze has moved forward in time by one to two weeks over the last century. Around the District, the average last freeze is in late March, while it holds off until mid-April in our colder suburbs west and north.
The first real taste of spring, or 70-degree day, has shifted as well. It used to come around this time in March. In recent years, it has moved up by about a month.
Temperatures are warming throughout the year
Climate “normals,” defined as the 30-year average weather which are updated every decade by the National Oceanic and Atmospheric Administration, show warming trends throughout the year in the Washington region.
In May, Washington’s climate normals will be updated based on the period 1991 to 2020 whereas for the past 10 years the period 1981 to 2010 was used.
https://www.washingtonpost.com/weather/2021/03/19/washington-dc-last-spring-freeze/?