Contents
- Weather in May
- Frequently asked questions
- Average temperature in May
- Average pressure in May
- Average wind speed in May
- Average humidity in May
- Average rainfall in May
- Average rainfall days in May
- Average snowfall in May
- Average snowfall days in May
- Average daylight in May
- Average sunshine in May
- Average sunshine days in May
- Average UV index in May
- Average cloud cover in May
- Average visibility in May
Weather in May
Temperature
Observing a slight rise in May, the average high-temperature in Portland shifts from April's moderate 58.6°F (14.8°C) to an enjoyable 67.1°F (19.5°C). May nights are characterized by a notable drop from daytime highs, with an average low-temperature of 44.2°F (6.8°C).Humidity
The average relative humidity in May is 72%.Rainfall
In May, the rain falls for 13.8 days. Throughout May, 1.77" (45mm) of precipitation is accumulated. In Portland, during the entire year, the rain falls for 173.1 days and collects up to 31.18" (792mm) of precipitation.Snowfall
In Portland, snow does not fall in April through October.Daylight
In Portland, the average length of the day in May is 14h and 56min.On the first day of May, sunrise is at 5:57 am and sunset at 8:18 pm. On the last day of the month, sunrise is at 5:25 am and sunset at 8:51 pm PDT.
Sunshine
In Portland, the average sunshine in May is 8.7h.UV index
In May, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: In May, the maximum UV index of 4 suggests these recommendations:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in May?
What is the average humidity in May?
How much does it rain in May?
When it does not snow?
What is the average length of the day in May?
What time are sunrise and sunset in May?
How many hours of sunshine does Portland have in May?
How high is the UV index in May?
Average temperature in May
Portland, OR
- Average high temperature in May: 67.1°F
The warmest month (with the highest average high temperature) is August (81.5°F).
The month with the lowest average high temperature is December (44.1°F).
- Average low temperature in May: 44.2°F
The month with the highest average low temperature is August (55°F).
The coldest month (with the lowest average low temperature) is December (34.7°F).
Average pressure in May
Portland, OR
- Average pressure in May: 30.03"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in May
Portland, OR
- Average wind speed in May: 4.2mph
The windiest month (with the highest average wind speed) is January (5.8mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).
Average humidity in May
Portland, OR
- Average humidity in May: 72%
The months with the highest relative humidity are January, February and December (83%).
The month with the lowest relative humidity is August (63%).
Average rainfall in May
Portland, OR
- Average rainfall in May: 1.77"
The wettest month (with the highest rainfall) is December (4.53").
The driest month (with the least rainfall) is July (0.31").
Average rainfall days in May
Portland, OR
- Average rainfall days in May: 13.8 days
The month with the highest number of rainy days is March (20.4 days).
The month with the least rainy days is July (4.9 days).
Average snowfall in May
Portland, OR
- Average snowfall in May: 0"
The month with the highest snowfall is March (1.5").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in May
Portland, OR
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is February (2.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in May /
Average sunshine in May
Portland, OR
- Average daylight in May: 14h and 5min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in May: 8h and 4min
The month with the most sunshine is August (Average sunshine: 10h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in May
Portland, OR
- Average sunshine days in May: 14.8 days
The months with the most sunshine days are July and August (23.8 days).
The month with the least sunshine days is March (8.3 days).
Average UV index in May
Portland, OR
- Average UV index in May: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in May
Portland, OR
- Average cloud cover in May: 46
The month with the most cloud cover is February (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 23).
Average visibility in May
Portland, OR
- Average visibility in May: 5mi
The months with the highest visibility are July, August and September (6mi).
The months with the lowest visibility are January, February, March, April, May, June, October, November and December (5mi).
Portland, Oregon, USA
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