Portland or fall area weather forecast

The rainy season usually begins in October

PORTLAND, Ore. (KOIN) — As the calendar turns to fall, the Pacific Northwest is preparing for a new season of weather. The scorching temperatures of summer give way to the cooler, more colorful tones of fall. The air becomes clearer as frost arrives, and our streets become rainier as more storms develop.

What is normal fall weather?

Autumn officially begins on the fall equinox (September 23) and moves to the winter solstice (December 21). Typically, daytime highs tend to cool away from the comfort zone in the 60s and 70s, into true sweater and puffer weather in the 50s and 40s by November and December.

The rainy season usually returns again in October. As more powerful storms with an active jet stream arrive, average monthly precipitation increases rapidly in Portland throughout the coming months.

Fortunately, the chances of snow in Portland are low before December. Cold temperatures during the last two months of the year. The average first freeze usually occurs in November and overnight lows drop into the mid-30s in December.

NOAA Climate Prediction Center fall 2023 outlook

The Climate Prediction Center relies on historical climate data and sophisticated weather models to provide extended weather forecasts across parts of the year. This year, fall 2023 forecasts indicate there is a greater possibility that temperatures during the months of September, October and November will be warmer than normal throughout the Pacific Northwest and southern United States. Regarding precipitation, forecasts indicate a greater likelihood of drier than normal conditions in the Pacific Northwest, and wetter than normal conditions in the southern coastal states.

For the Pacific Northwest, this could signal longer periods of milder, drier weather in the coming months, compared to the usual mild, cool, and rainy fall pattern we’ve become accustomed to.

It is important to remember that a climate forecast is different from a complete, detailed weather forecast. These forecasts extend months ahead of time when the weather can be truly unpredictable. Although the forecast calls for a warmer and drier fall, impactful weather will still arrive at times over the coming months, bringing wet, windy and cold moments to the Portland metro area.

The best thing to stay on top of the weather is to follow the forecast with the KOIN 6 Weather team as we head into the coldest and windiest months of the year.