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| A summer's day in Washington, D.C. |
The nation’s capital has seen no shortage of extreme June weather over the last two decades. Some have been very rainy while others have been quite hot and dry. If June were to end today, then it would rank among DC’s warmest and driest on record.
Five of DC’s 10 warmest June’s have occurred since 2008. Official weather records in the nation’s capital date back to 1871 and are kept by NOAA. Having five of the 10 warmest so recently is a remarkable feat. What has contributed to many of DC’s warmest June’s having occurred relatively recently, in addition to a changing climate, is a more pronounced urban heat island effect.
It wasn’t until recent decades that the DMV (DC, Maryland and Virginia) has become as urbanized as it has with so much ground covered by buildings and roads with automobile traffic. Warmer overnights are largely what has led to many of our warmer than average months in recent decades. That’s because urban areas don’t cool off as quickly or as much as more rural areas that have more green space with fewer buildings and roads. Not surprisingly, the most recent of DC’s Top 10 coolest June’s occurred more than 50 years ago in 1972.
Three of DC’s five wettest June’s have also occurred in the last 20 years. While it might make sense that a rainier June could also be cooler than average, that’s not always the case. For example, June 2015 finished as DC’s second wettest, but was also DC’s seventh warmest with 12 days of 90-degree heat. The nation’s capital has averaged between seven and eight 90-degree June days over the lats 30 years, according to NOAA data.
Higher temperatures can hold more water vapor which means warmer weather can feature rainier days. June 2015 had three days more than 2” of rain occurred. As such, roughly 64% of DC’s rainfall in June 2015 occurred on just those three days. On the opposite end of the spectrum were June 2024 and June 1976. Each of those months rank among DC’s Top 10 warmest and Top 10 driest June’s.
DC’s
wettest June’s (Source: National Weather Service)
1. 14.02" (2006)
2. 11.94" (2015)
3. 11.53" (1972)
4. 10.94" (1900)
5. 9.97" (2013)
6. 8.55” (1883)
7. 7.87” (2003)
8. 7.53” (1916)
9. 7.41” (1929)
10. 7.40” (1968)
DC’s coolest June’s (Source: National Weather Service)
1. 65.9° (1907)
2. 67.0° (1903)
3. 68.6° (1927)
4. 69.1° (1926, 1878)
5. 69.6° (1897)
6. 69.7° (1916, 1910)
7. 69.9° (1886)
8. 70.2° (1972, 1955)
9. 70.4° (1912)
10. 70.6° (1915)
