Weather in Portland in May 2025
Average weather
Average temperature in Portland in May
The temperature in May is +75°F on average, with a range between a maximum of +91°F during the day and a minimum of +45°F at night.
The average maximum temperature goes up 12% by the end of the month, compared with the beginning of the month, from +63°F to +68°F.
Is Portland warm or cold in May?
Portland is typically mild in May.
Maximum temperatures go up compared to the previous month from +63°F to +70°F. The minimum temperature also goes up from +43°F to +48°F.
Pack a light jacket as it will be warm in the day and cool in the evenings.
Take a look at how May is compared to other months in Portland:
Climate in Portland in May
| April | May | June | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +63°F | +70°F | +75°F | ||||
| Min. temperature | ||||||
| +28°F | +34°F | +39°F | ||||
| Max. temperature | ||||||
| +88°F | +100°F | +115°F | ||||
| Rainfall | ||||||
| 145 mm | 79 mm | 59 mm | ||||
| Wind | ||||||
| 1 m/s | 1 m/s | 1 m/s | ||||
| Humidity | ||||||
| 75% | 72% | 69% | ||||
| Air pressure | ||||||
| 1017 HPa | 1016 HPa | 1016 HPa | ||||
| Sunny days | ||||||
| 2 | 3 | 5 | ||||
| Cloudy days | ||||||
| 7 | 11 | 12 | ||||
| Rainy days | ||||||
| 20 | 16 | 12 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
May often has better weather than April. It’s getting warmer as May arrives. The average maximum temperature goes up from +63°F to +70°F during the day. As May arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 145 mm to 79 mm. It feels drier, as humidity decreases from 75% to 72%. The average wind speed doesn’t change much during May, staying around 1 m/s. The good news is there are likely to be more sunny days in May, from 2 to 3.
June brings much the same weather, it remains good.
Wind
The average wind speed is 2 m/s getting up to 4 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Portland is gradually increasing during May, going from 2 m/s to 3 m/s over the course of the month.
Rain
How was the weather last May in Portland?
Climate Change Over the Years
The climate in Portland in May has not changed that much over the last 43 years.
The average temperature was the lowest in 2011 (+61°F) and the highest in 2015 (+67°F). The driest year was 1985 with only 736 mm of rainfall, and the wettest year was 2021 with 4296 mm.
FAQ
Is May a good time to visit Portland?
Can you sunbathe in Portland in May?
Is Portland rainy in May?
Is it sunny in Portland in May?
Other cities in USA
Monthly weather in Portland
Source of the data
For this page, we’ve looked at the typical weather in Portland, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.