Shaped like a “W” for warm

After the first five days of the month, all of which in the 90s, it became clear early that July would finish warmer than normal. Given that the prior sixteen months had also been warmer than normal, and that forecasts had been calling for continued warmth, we shouldn’t have been surprised.

But the fact that Seattle broke another all-time monthly record—the sixth such since October—is pretty astounding. In fact, with an average temperature of 71.2 degrees, July 2015 went down as Seattle’s warmest month ever recorded, surpassing August 1967 by 0.1 degrees.

It was another drier-than-normal month, too. With 0.09 inches recorded at Seatac, it was the 9th driest July on record. Normally we see 0.70 inches. Since May, only 0.90 inches has fallen, which is the least for that period.

That’s at Seatac, though, where official records are taken. There was one Puget Sound Convergence Zone event on Sunday July 26, which provided northeast Seattle with nearly an inch of rain. Amidst the heavy drizzle, SPU’s Magnuson Park rain gage recorded 0.33 inches in 30 minutes, which was good for a 2-year recurrence. Fortunately no drainage impacts were reported.

NWS Seattle July Climatology
SPU Water Supply Outlook

– JRH