May weather forecast
Portland, OR

A colorful autumn view of the outline of Portland City, Oregon, USA
A colorful autumn view of the outline of Portland City, Oregon, USA

Weather in May

The last month of the spring, May, is an enjoyable month in Portland, Oregon, with temperature in the range of an average low of 44.2°F (6.8°C) and an average high of 67.1°F (19.5°C).

Temperature

In Portland, the average high-temperature in May marginally rises from a mild 58.6°F (14.8°C) in April to an enjoyable 67.1°F (19.5°C). In May, the average low-temperature is 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 the month, sunrise is at 5:57 am and sunset at 8:17 pm. On the last day of May, sunrise is at 5:25 am and sunset at 8:51 pm PDT.

Sunshine

In May, the average sunshine in Portland is 8.7h.

UV index

The average daily maximum UV index in May in Portland is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 4 in May transform into the following instructions:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the average humidity in May in Portland?

In May, the average relative humidity in Portland, Oregon, is 72%.

How much does it rain in Portland in May?

In May, in Portland, Oregon, the rain falls for 13.8 days. Throughout May, 1.77" (45mm) of precipitation is accumulated.

When it does not snow in Portland?

In Portland, snow does not fall in April through October.

How many hours of daylight does Portland have in May?

In May, the average day length in Portland is 14h and 56min.

When are sunrise and sunset in May in Portland?

On the first day of May in Portland, Oregon, sunrise is at 5:57 am and sunset at 8:17 pm. On the last day of the month, sunrise is at 5:25 am and sunset at 8:51 pm PDT.

How many hours of sunshine does Portland have in May?

In Portland, the average sunshine duration in May is 8.7h.

What is the UV index reading in May in Portland?

The average daily maximum UV index in May is 4. A UV Index estimate of 3 to 5 represents a moderate vulnerability from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Portland, OR

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).

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Average pressure in May
Portland, OR

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).

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Average wind speed in May
Portland, OR

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).

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Average humidity in May
Portland, OR

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%).

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Average rainfall in May
Portland, OR

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").

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Average rainfall days in May
Portland, OR

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).

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Average snowfall in May
Portland, OR

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").

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Average snowfall days in May
Portland, OR

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).

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Average daylight in May /
Average sunshine in May
Portland, OR

Average daylight in May / Average sunshine in May - Portland, OR
  • Average daylight in May: 14h and 56min

The month with the longest days is June (Average daylight: 15h and 38min).
The month with the shortest days is December (Average daylight: 8h and 46min).

  • Average sunshine in May: 8h and 42min

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).

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Average sunshine days in May
Portland, OR

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).

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Average UV index in May
Portland, OR

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).

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Average cloud cover in May
Portland, OR

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).

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Average visibility in May
Portland, OR

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).

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