Portland weather
Our guide to the weather in Portland during May
We've looked at the most up-to-date weather data for Portland, covering the last 12 years up to 2026, plus we've asked our team of travel bloggers for their first-hand experiences in order to answer the most frequently asked questions about Portland weather in May.
What's the temperature like in Portland during May?
The temperature reaches around 20℃ during the daytime in May, falling away to 7℃ at night. The UV index will be moderate at this time of year, so not something to worry about for the average person. However, if you're going to be outside for long periods it's worth wearing a broad spectrum SPF 30+ sunscreen and UV-blocking sunglasses. Remember that bright surfaces, such as water and sand increase UV exposure.
Does it rain in Portland during May?
On average, there will be 7 rainy days during the month, amounting to 97.9mm in total. That's a significant amount of rain. For comparison, the wettest months in the UK typically sees between 80mm and 100mm, depending on where you are. There's a small chance that you'll catch a thunderstorm during your trip.
Is it windy in Portland during May?
You're unlikely to experience any strong winds. Expect a light breeze that picks up slightly at times in May. With moderate air temperatures, any breeze will feel cool.
Weather in Portland
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