Warm September, Wet October?

As I mentioned in the previous blog, there was the potential for September 2025 to set a record for the warmest September ever recorded in Spokane. Now that we’ve turned the calendar, we can definitely say that September 2025 was the warmest on record, going back to 1881.

Here’s the top 10 list. 



A few things to note. September 2024 is third on the list of warmest Septembers. And 2022 is in 5th place. Is this a trend, or is something going on at the Spokane Airport?

If you’ve read other blog entries you know I’ve pointed out that the temperature sensor at Spokane Airport is surrounded by a lot of concrete runways and tarmacs, which could contribute to a warm bias. But in this case, that’s not the sole cause. 

If we look at other stations in the Northwest, the story is the same. Below is a map showing the ranking of 2025 temperatures in September. Missoula and Yakima also had their warmest September on record, with other locations coming close to setting records, including Lewiston, Portland and Kalispell.


A couple of other points to make. 
  • Deer Park had 20 days in September 2025 with a high at or above 80.  The average is only 10 days. 
  • Deer Park averages 4 nights of freezing temperatures in September. In 2025, none occurred.  We’ll probably have our first freeze this weekend or early next week. 
  • For rainfall, Spokane received 0.48” in September. This is a little over half of the normal, but far from being near the top of the list for driest Septembers.
Will this pattern continue into October?  The Climate Prediction Center folks say “no”.  Here’s their outlook for the month. 




For temperatures, there’s no clear signal of warm vs cool. For precipitation, the anticipation is that we’ll receive above normal amounts. Remember, on average October is the 4th driest month in the inland Northwest, so “above normal” doesn’t necessarily mean a deluge.

We’ll contribute to that total in the first few days of the month, as our showery pattern continues.  We should dry out this weekend and stay dry through much of next week.  But then wetter weather may return for the second and third weeks of October. 

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