Portland Weather in May
United States · Oceanic climate · Data averaged from 2020-01-01 to 2024-12-31 (5 years)
May in Portland sees average temperatures ranging from a low of 8.4°C (47.1°F) to a high of 18.9°C (66.0°F), with a mean of 13.3°C (55.9°F). Compared to the annual average of 11.9°C (53.4°F), this month is 1.4°C warmer than the yearly norm. Precipitation averages 97.6mm, making it approximately 22.0mm drier than the monthly average of 120.0mm. The city receives an average of 10.1 hours of sunshine per day during May, with relative humidity averaging 73.8%. Wind speeds reach an average maximum of 16.0 km/h. For travelers, this month offers a temperature experience in Portland, with drier-than-average conditions compared to the rest of the year.
Portland's climate is similar to Seattle but with slightly warmer summers and cooler winters. I visited during the famous rose festival in June and found the weather ideal. The data shows that the best time to visit is June to September, when the rainfall is minimal and the city's famous outdoor culture thrives. The winter months are grey and wet but the city's coffee shop culture makes it cozy.
May vs Adjacent Months
| Metric | April | May | June |
|---|---|---|---|
| Mean Temp | 9.4°C (48.9°F) | 13.3°C (55.9°F) | 17.1°C (62.8°F) |
| Rainfall | 109.2mm | 97.6mm | 77.6mm |
| Sunshine | 8.9 hrs | 10.1 hrs | 11.7 hrs |
| Humidity | 75.5% | 73.8% | 68.6% |
| Wind | 16.7 km/h | 16.0 km/h | 16.2 km/h |
| Rainy Days | 18.2 | 17.0 | 12.2 |
| Snowfall | 7.4 cm | 0.0 cm | 0.0 cm |
Seasonal Context
May falls in Spring in the Northern Hemisphere. Spring is a transitional season with temperatures rising from winter lows. For travelers visiting Portland in May, the data indicates mixed conditions based on the combination of temperature, precipitation, and daylight hours.
Frequently Asked Questions
What is the average temperature in Portland in May?
The average temperature in Portland during May ranges from 8.4°C (47.1°F) to 18.9°C (66.0°F), with a mean of 13.3°C (55.9°F).
How much does it rain in Portland in May?
Portland receives an average of 97.6mm of precipitation in May, spread across approximately 17.0 rainy days.
What should I pack for Portland in May?
Based on May weather data, pack warm layers, a medium jacket, and waterproof outerwear.
Is May a good time to visit Portland?
May is a cooler month, suitable for travelers who prefer mild weather and fewer crowds. Pack warm layers and enjoy indoor attractions.
Other Months for Portland
Cities with Similar May Climate (Oceanic)
Data Source: Open-Meteo historical archive (2020-01-01 to 2024-12-31). Daily measurements aggregated into monthly climate normals. Coordinates: 45.52°, -122.68°. Timezone: America/Los_Angeles. Last updated: 2026-07-30.