Portland in December
December is right in the heart of summer for Portland, and the weather has a definite personality this time of year.
Expect the mercury to hit around 21.5 degrees during the day and settle at 13.2 degrees after dark. That's solidly pleasant territory. Great for being outdoors.
December is 3.6 degrees warmer than the yearly average here.
Rainfall in December averages 41mm over about 7 days. That means roughly a 23% chance of rain on any given day, decent odds for a dry day.
Sunshine-wise, December delivers around 24.2 MJ/m2 of daily solar radiation. UV sits in the extreme category. Sunscreen, hat, and sunnies are all essential. You can burn in under 10 minutes.
December earns a 9.1/10 on our Comfort Score. This is prime time.
Packing tip: bring layers you can peel on and off, and SPF 50+ sunscreen and a hat.
Check the data table below for the full picture, or compare Portland in December with another destination.
December at a Glance
Temperature Range
Daily temperature range in December. The bar shows the typical spread between overnight lows and afternoon highs.
What to Pack
- Layered clothing for mild to cool conditions
- A light rain jacket just in case
- High SPF sunscreen (50+), sunglasses, and UV-protective clothing
Coming From Overseas?
How December in Portland stacks up against major cities around the world.
About 14 degrees warmer and considerably drier.
About 16 degrees warmer and considerably drier.
About 10 degrees warmer and considerably drier.
How December Compares
Portland's monthly climate at a glance. December is highlighted.
| Month | Max | Min | Rain | Comfort |
|---|---|---|---|---|
| Jan | 21.2 | 14.6 | 71mm | 8.2 |
| Feb | 22.2 | 13.5 | 5mm | 10.0 |
| Mar | 21.9 | 13.7 | 14mm | 9.2 |
| Apr | 16.9 | 11.3 | 54mm | 4.0 |
| May | 15.9 | 9.7 | 23mm | 3.5 |
| Jun | 13.2 | 7.6 | 37mm | 1.5 |
| Jul | 13.0 | 7.4 | 84mm | 1.0 |
| Aug | 16.2 | 9.4 | 70mm | 3.4 |
| Sep | 14.8 | 10.0 | 90mm | 2.3 |
| Oct | 17.7 | 10.4 | 68mm | 5.6 |
| Nov | 19.8 | 12.0 | 91mm | 7.1 |
| Dec | 21.5 | 13.2 | 41mm | 9.1 |