Has Eastern Washington Gotten Drier or Warmer?

 With the recent grass/range fires in Eastern Washington, there is some interest in whether conditions there have gotten drier or warmer.   

 How unusual have precipitation and temperature been this year?

Let's find out!

I will start with the NOAA Climate Division dataset, which is derived from multiple climate observation locations in each division (the climate division map for Washington State is shown below).  

For Division 8, on the eastern slopes of the Cascades, the history of summer precipitation and temperature since 1960 is shown below.

For precipitation, there is little long-term trend.

For temperature, there is a warming trend of about 0.2F per decade.  Some of that represents the global warming signal.

Moving to the lower-elevation Columbia Basin, there is again little overall trend in precipitation over the period, but there have been a few dry years in the past decade.

The temperature plot for that area shows warming, particularly during the past decade.  Some of that warming undoubtedly reflects the global warming signal (although land use changes, urbanization, and other factors are certainly significant as well). Same upward rate of 0.2 F per decade.

 What about this year?   

Here are the plots of precipitation and temperature at Ellensburg in eastern Washington for June 1 to July 28.

A small warming trend in temperatures, with this year not being extreme at all-- near the long-term mean.

For precipitation, there is a LOT of historical variability, with this year being relatively low (fifteenth lowest out of 67)

In short, conditions in eastern Washington have hardly been exceptional for the first half of summer 2026, with a very modest warming signal evident.  

This is why the fuel moistures were near normal.

The only reason we had significant grass fires was due to a huge amount of lightning, which has little to do with global warming.