How Unusual Was this Summer's Weather?

Now that we have entered fall, it is time to evaluate whether our summer weather was unusual.

Are summers getting warmer or drier in Washington State?

Starting with the overall view for the entire state, below is the July 1-Sept 26 precipitation difference from normal.  

A complex pattern.  The western slope of the Cascades (where there was little fire) was drier than normal, while the eastern slopes (with more fire than normal) were WETTER than normal.  

The majority of the state was near normal for temperature (light green or yellow below), with a few areas a bit above normal 

In short, not an exceptional summer period for temperature and precipitation.

What about the long-term trends in summer temperatures?   

Average daily temperatures have risen over the past 70 years at Hoquiam, Olympia, Yakima, and Spokane by about 2-3.5 F over the period.

In contrast, the trend in daily high (max) temperatures has been very small west of the Cascades, about 4F at Yakima and roughly 1°F at Spokane.

Finally, for precipitation, there is modest summer drying in the west and a small downward trend east of the Cascades.   But there is very little precipitation during the summer in any case.

Fortunately, there is no overall downward trend in annual precipitation, so the region should be ok with its water supply.

The bottom line of this blog.  

This summer was not that unusual for temperature and precipitation in Washington State (but there was an unusual lightning event in July).  

The region is slowly warming, although high temperature extremes are hardly changing.  Annual precipitation is steady, but our dry summers are getting slightly drier.