August also marked the tenth straight month with warmer-than-average temperatures.
During August, DCA saw two record high low temperatures in the first first week on August 4 (79 degrees), August 6 (78 degrees tie). Otherwise, there were no high (or low) temperature records established this month despite the very warm average.
August had the same number of 90-degree as 80-degree days with only one 70-degree day (78 on Sunday, August 19).
Both Dulles (IAD) and Baltimore-Washington International (BWI) had warmer than average Augusts, but by not as much as DCA.
Both DCA and IAD saw lower-than-normal precipitation, but BWI saw a surge in late month precipitation that brought that area to a strong surplus (+2.53” for month). That spoke to the convective nature of precipitation both in July and August when some areas saw significantly more than others.
At DCA, August was the 56th driest month and June-August period was the 25th driest on record. So, yes, it has been running drier than normal for much of the area. But no, we are not at or near record-breaking levels for dryness at this point.
2012 continues to be the warmest year on record. With the August data, we now find DCA running 1.6F warmer than the previous record-holder, 1991. At this point, we would need to see a significantly cooler autumn and early winter to offset the strong warm gains we have seen this year.
The current thinking for September is still a warmer-than-normal month, but much of it may come from this first week. The latest guidance suggests a cooler trend to the pattern next week at least. You can see the final National Weather Service outlook for September 2012 for the U.S. here.
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: