Portland Weather in May
Thinking of visiting Portland in May? Expect pleasant temperatures reaching 20°C (68°F) during the day, dropping to 9°C (48°F) at night, and note that quite a bit of rainfall is likely.
Rainfall in Portland in May
Climate statistics over the past 30 years suggest around 13 days of rain, with 71 mm (2.8 in) average for the month. Neither particularly heavy nor particularly frequent, the rain this month is about average. A light jacket should be enough on most wet days.
Temperature in Portland in May
The temperature in Portland in May is excellent. Daytime highs reach 20°C (68°F), with nights dropping to 9°C (48°F). This creates a mild day-to-night pattern that is generally easy to manage with the right clothing. Nights fall to 9°C (48°F), which is cold enough to feel it indoors too. A good thick duvet makes all the difference for a comfortable night's sleep.
Sunshine in Portland in May
The days are predominantly sunny, with an estimated total of around 276 hours of sunshine. These sun-filled days are perfect for playing sports, visiting parks, or going for a bike ride.
Wind Speed in Portland in May
May has wind speeds averaging 3 m/s (6 knots). You can expect comfortable light winds that steadily move flags and feel mild throughout the day. Since this is an average, daily conditions vary from gentle winds to more active breezes.If you're inclined towards comfortable temperatures and drier conditions, May is a good time to visit Portland.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Portland's climate page.
Portland Temperature in May
Min Temperature
9°C (48°F)
Max Temperature
20°C (68°F)
Chance of Rain
44%
Precipitation
71 mm (2.8 in)
Rainy days
13 days
Humidity
69%
Windspeed
3 m/s (6 knots)
Sunshine
276 hours
Percentage Sunshine
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Portland typically stay consistent throughout May, with daily highs averaging around 20°C (68°F). Nights are cool, with lows typically ranging from 8°C (46°F) to 12°C (54°F).
Average temperatures in May
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in May
Historical weather for Portland in May
Browse day-by-day weather records for Portland spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Portland historical weather extremes in May
Our historical data for Portland spans 1976 to 2026, revealing these weather extremes.
- The warmest day in May was on May 28, 1983, with a maximum of 38°C (100°F).
- On May 22, 2013, Portland saw its coldest May day with temperatures maxing out at 9°C (48°F).
- Nighttime temperatures dropped to 3°C (37°F) on May 10, 1999, marking the coldest May night on record.
- The wettest day in May Portland was on May 31, 1993 with 45 mm (1.8 in) of precipitation.
Best Places in the United States of America in May
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in May →
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What to Wear in Portland in May
Comfortable temperatures call for an easy wardrobe in May. Pack summer basics like t-shirts and shorts, but include a light jacket for cooler moments. A pair of comfortable walking shoes is essential. Wet weather is likely, so pack waterproof gear for multiple rainy days. Don't forget sun protection, sunglasses, sunscreen, and a hat. These are all good ideas with this much sunshine.What To Do in Portland in May
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Portland's climate page.
Temperature Rainfall Sunshine Humidity Wind Speed
See the full Portland climate overview or explore weather in the United States of America.
