WINTER OUTLOOK 2025-2026
By Rod Hill on 2025-10-28
WINTER OUTLOOK 2025-2026
My winter outlook always begins with recognizing the expected enso cycle and this year is similar to last winter. 2024-2025 saw a neutral pattern develop into a weak La Nina by the end of December and transition back to Neutral in February. This winter the pattern begins as a weak La Nina and is expected to fall back to Neutral conditions during the month of January. La Nina winters are known to be wet or active due the jet stream entrance quadrant off of the Pacific aligning into the Northwest. The period of weak La Nina this winter is likely to be slightly cooler than the winter of 2024-2025, which could lead to cooler temperatures and a better chance of valley snow.
Research shows weak La Nina winters for Portland actually average slightly drier than normal by nearly 2.00" total precipitation for the combined months of November through March. However, last winter or rainy season was an exception as Portland was more than an inch above normal for the period.
Five seasons of comparison are listed on the graphic below. The take away is potentially illuminating and
shows potential for a much colder than normal winter. Both the winters of 2016-2017 and 2022-2023 were
more than 9 degrees F colder than normal when totaling each month's negative mean temperature departure.
Each of the two seasons also produced 8" or more of snowfall. Keep in mind the only snow Portland saw
last winter was 3" in February. Much of my winter outlook conclusions come from averages of the comparison
year data set that I establish.
My research data over the years includes pressure height indices and flow patterns at 500 mb or 18,000 feet. Assuming the projection data is accurate, the information can be helpful in seeing into the future.
Notice November and January are expected to be similar to last season. However December could be much colder than 2024. The flow pattern shows heaviest December rainfall to flow into California, potentially leaving our region drier than last December. Also my mean temperature projection is 4 degrees F cooler than one year ago.
Hopefully the information presented has given you an understanding of my process and some of the data I use to determine conclusions. Here is my Portland temperature outlook for this rainy season / winter. December and February have the best chance to see colder than normal temperatures. While the door is open for an extreme cold month or two, I see no chance of significantly warmer than normal months. Overall the coming season is expected to average near normal within 2 degrees.
Valley snow is always a headline and this year, like last, the data shows Portland to see snow not ice. Last winter Portland only picked up 3" of snow that fell in February. This winter the snow chances look greater. I like the odds of at least one 6" plus snow event. While some snow is possible in December, odds favor a heavier snowstorm event to be possible in January and most likely in February.
Total precipitation November through March is expected to be some 2.00" drier than last season and slightly below normal for the 5-month period.
Mt. Hood snow was the crown of my outlook one year ago! My projection on the heals of a 2023-2024 season that had basically zero snow at Government Camp Christmas week, called for impressive turn about with an early deep build of the snow pack. In fact, I was correct as Cascade resorts reported the earliest opening dates in decades. This season should also get off to a decent start and have solid bases Christmas week. Note that the expected weak La Nina to Neutral season will most likely produce a snowpack between 88 and 104% of normal.
My projection for Mt. Hood resorts will be similar to slightly less than Christmas week of 2024.
This concludes my winter outlook for 2025-2026. Overall, I expect a slightly drier season for Portland than one year ago, a better chance to see a 6-8" snowstorm and near normal to a little colder than normal temperatures. January will likely once again be the driest month of the season. It is important to note that the overall flow pattern and indices I track as a forecaster are very similar to slightly cooler than 2024-2025.
Happy Winter!
Meteorologist Rod Hill
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