It was a topsy-turvy month as the second half was actually warmer than the first half, not the usual steady decline as we move through Autumn. Splitting the month in two, the Average Max/Min/Mean Temperatures for Oct. 1st-15th vs. 16th-31st were thus: 61.7°/44.7°/53.2° vs. 61.9°/48.1°/55.0°. This was mainly due to a persistent end-of-month easterly wind that funneled in mild air through the Columbia River Gorge, especially elevating minimum temperatures. From the 22nd-29th, the Avg. Min. Temp. was 50.0°, well above the normal for late October, while only one Min. Temp. ≥50° occurred over the first half of the month (the warmest Minimum was 56.6° on the 27th). The average monthly diurnal temperature range was 15.3°, with the greatest day being 26.5° (4th), the least only 6.0° (20th). The season’s first frost occurred the morning of the 14th when the Minimum Temperature fell to 36.5°, the coldest reading here since 35.8° on 4/3/2017.

Average Monthly Maximum: 61.8°
Average Monthly Minimum: 46.5°
Monthly Mean: 54.2°


Monthly High Maximum: 70.1° (4th & 5th)
Monthly Low Maximum: 52.1° (20th)
Monthly Low Minimum: 36.5° (14th)
Monthly High Minimum: 56.6° (27th)


Maximums ≥70°:  3
Maximums ≥65°: 10
Maximums ≥60°: 20
Maximums ≥55°: 27
Minimums ≤50°: 26
Minimums ≤45°: 13
Minimums ≤40°:  2



There were only two significant periods of rain this month, quite a contrast to the previous October when measurable rain (≥0.01″) fell on 30 of the 31 days; this month there was half that amount, 15 days. The first rainy period this month occurred from the 10th-13th, dropping a total of 1.44″. The more significant event impacted the area from the 18th-22nd when 4.35″ soaked this location. The two events combined for 95% of the October total.

Total Precipitation: 6.08″
Maximum Calendar Day: 1.65″ (21st)


≥0.01″: 15
≥0.25″:  6
≥0.50″:  4
≥1.00″:  3



The month saw 12 clear days, 15 partly cloudy days, and only 4 cloudy days, much less cloudier than normal. There were 15 days with Fog but only 2 of these were heavy (<1/4 mile visibility).



Featured cover photo is of Cumulus Congestus during the evening of 10/12/2017, Happy Valley, Oregon.





Double Rainbow, evening of 10/11/2017, Happy Valley, Oregon.


Colorful Autumn leaves, early evening 10/24/2017, Aurora, Oregon.


Spotted leaf, 10/27/2017, Happy Valley, Oregon.


  1. Wow, those are some beautiful pictures! I particularly enjoy the cumulus congestus and double rainbow. And yes, this October was much, much drier – it made biking to work far more comfortable. 🙂

    As always, thanks so much for your detailed report.

    1. Thanks for the comments, Charlie! Yes, that Cumulus Congestus was taken while out walking the doggies, looking SW soon before sunset. The double rainbow was also taken near my house, looking SW also. Hoping November can bring us some active wx patterns!

  2. Great report Jeff. You sure are in a better spot for great pictures! My new spot is better than my old one, but still pretty mundane compared to where you are and what is available to you during a month’s time. Thanks again, happy November! Hope you saw the post about Herb’s party coming up fast this Sat Nov 11. Cheers! Kevin

    1. Hey Kevin. Happy November to you as we move closer to snow season! I see you’ve had your first hard freeze of the season as it’s finally feeling like Autumn in your area. I saw that both BWI and DCA tied record lows this morning, Nov. 11th (21° and 26°, respectively). Impressive, especially for DCA.
      With the La Niña pattern we’re expected to be in into Spring, here in the PNW that usually means cooler than normal temps, which could translate into better chances for snow here in the Willamette Valley (and even heavier amounts than normal in the Cascades). Hoping that my snow board gets good use again this winter (16 total inches fell on it last winter). Hoping you get some decent snow this time around.

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