(Left) Top 10 warmest springs. (Right) Top 10 warmest Mays.

The warm spring pattern persisted through May with the monthly average temperature end up about 5.4 degrees warmer than normal, third warmest on record.

May Average Temperatures at 71.4F (+5.4F)

March-May Average Temperature at 62.2F (+5.7F)

The top three warmest Mays have occurred since 1990, but 60% of the years on the top ten list are still before 1960.

One record high was set during May the area: on May 28 Dulles hit 90, tying the record from 1991. We saw a handful of record high minimum temperatures set at Dulles and one at Reagan National.

At Reagan National, 58% of the days saw highs in the 80s or higher. Only 32% saw lows below 60-degrees.

As suspected last week, most of the work for the March-May record was completed by the super-warm March pattern in eastern North America.

Here are the contributions from each month to this new record:

Number of degrees above normal for the spring months


Precipitation started catching up in May from a very dry spring status, but it was not enough to stop 2012 from becoming the 10th driest spring on record (May by itself was 66th driest).

May Average Precipitation at 3.12” (-0.89”)

March-May Average Precipitation at 6.16” (-4.37”)

(Left) Top 10 driest springs. (Right) Rainfall during May at the three airports.

Prevailing weather pattern: persistence wins

And June?

As noted yesterday afternoon, the first 1/3 of June is expected to arrive cooler than normal due to a nice cool, early summer trough over the Eastern U.S. By around mid-month, we could see a return to hotter weather, but for now it looks like we’ll be taking an extended break from the 90+ temperatures that hit our area earlier this week. When the hotter weather returns, it is not clear how long it sticks around (it may be another series of brief events again).

The National Weather Service once again paints D.C. with EC for both temperature and precipitation throughout our area. EC means Equal Chances of below, normal, or above normal temperatures (33.3 chance each).

Further information

The National Weather Service publishes nice monthly assessments usually within a week of the close of each month (should be available shortly):

You can click on your closest airport location here:

Reagan National (DCA)

Dulles Airport (IAD)

Baltimore-Washington (BWI)

Historical Washington, DC data provided by Speedwell Weather and NOAA. See also: Ian’s excellent rundown on May climatology