The saying goes that records are meant to be broken, and when it comes to summertime heat around here, that saying sure seems to have extra meaning these days. Today’s record of 101 in Washington, D.C. may be threatened. Just over a week ago (on June 21, 2012), the latest in a string of June daily records was broken here in D.C. (as recorded at Reagan National Airport) when the thermometer reached 99 degrees for a high.
That record on the 21st was the 6th high temperature record set or tied in June over the past three years, and the 15th since 1988. In other words, half of the overall June daily high temperature records covering the last 142 years have been set or tied in just the most recent 25 years.
Going back to last year, D.C. tied the daily record for the warmest daytime temperature in June at 102. Then the month ended up the third warmest June on record, and this was all following on the heels of the hottest June on record in 2010.
On the flip side, no record lows have been set or tied in June since 1992. If we wanted to grab half of the record lows for June, we’d need to go back to the 1920s. Quite a difference.
D.C. also set a record for warm overnight low temperatures on the 21st with a reading of 78. This measure of temperature extremes, like that for highs, is heavily weighted toward recent times, with 16 -- more than half -- set or tied since 1988.
As with record lows, cool daytime maximum temperatures have seemingly been harder and harder to come by, though there have been several somewhat recent occurrences. We almost got one earlier this month on the 18th when it was 71 for a high (record 69 in 1947).
While the increase in low temperatures is likely tied in some way to the urban heat island, high temperature peak levels have more or less remained steady through the record. The difference is that, over recent years, the frequency of those record-level high temperatures have increased locally.
Whether that’s a meaningful trend may not yet be determined. However, if you’re betting, it might be wise to continue to bet warm. The next June record high might be right around the corner.
Data used in this post was obtained through National Weather Service Baltimore/Washington.