Portland in May
Planning a trip to Portland in May? Here's the honest weather briefing for what autumn looks like on the ground.
Daytime highs average 15.9 degrees, dropping to 9.7 degrees overnight. That's a 6-degree swing between day and night. Manageable with a decent layer, and you'll warm up by midday.
At 15.9 degrees, May sits 2.0 degrees below the annual average of 17.9 degrees.
The rain data says 23mm over 6 days. Light enough that it won't ruin your plans.
Solar exposure averages 8.5 MJ/m2 per day in May, with UV levels in the moderate range. Sunscreen is still wise, especially if you burn easily.
With a Comfort Score of 3.5/10, May is not the most comfortable time to visit.
For your suitcase: layers you can peel on and off.
Check the data table below for the full picture, or compare Portland in May with another destination.
May at a Glance
Temperature Range
Daily temperature range in May. The bar shows the typical spread between overnight lows and afternoon highs.
What to Pack
- Layered clothing for mild to cool conditions
- Extra layers for chilly nights
- A light rain jacket just in case
Coming From Overseas?
How May in Portland stacks up against major cities around the world.
About 2 degrees cooler and considerably drier.
About 7 degrees cooler and considerably drier.
About 8 degrees cooler and considerably drier.
How May Compares
Portland's monthly climate at a glance. May 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 |