May weather forecast
Seattle, WA

Beautiful dusk skyline over the giant skyscrapers of Seattle, Washington
Beautiful dusk skyline over the giant skyscrapers of Seattle, Washington

Weather in May

May, the last month of the spring in Seattle, is a comfortable month, with an average temperature varying between 64.8°F (18.2°C) and 44.8°F (7.1°C).

Temperature

In May, the average high-temperature slightly increases from a moderate 56.5°F (13.6°C) in April to a comfortable 64.8°F (18.2°C). In Seattle, Washington, the average low-temperature is 44.8°F (7.1°C).

Humidity

In May, the average relative humidity is 75%.

Rainfall

In Seattle, during May, the rain falls for 7 days and regularly aggregates up to 0.39" (10mm) of precipitation. Throughout the year, there are 84.2 rainfall days, and 5.2" (132mm) of precipitation is accumulated.

Snowfall

April through October and December are months without snowfall.

Ocean temperature

In Seattle, the average water temperature is 46.6°F (8.1°C).
Note: Swimming in 46.6°F (8.1°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

Daylight

In Seattle, the average length of the day in May is 15h and 10min.
On the first day of the month, sunrise is at 5:51 am and sunset at 8:21 pm. On the last day of May, sunrise is at 5:16 am and sunset at 8:57 pm PDT.

Sunshine

In Seattle, Washington, the average sunshine in May is 9.2h.

UV index

In Seattle, the average daily maximum UV index in May is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 4 in May interpret into the following advice:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in May in Seattle?

In Seattle, Washington, in May, the average high-temperature is 64.8°F (18.2°C), and the average low-temperature is 44.8°F (7.1°C).

What is the average humidity in May in Seattle?

In May, the average relative humidity is 75%.

How many days does it rain in May in Seattle?

In Seattle, in May, during 7 rainfall days, 0.39" (10mm) of precipitation is typically accumulated.

When it does not snow in Seattle?

In Seattle, Washington, snow does not fall in April through October and December.

What is the ocean temperature in May in Seattle?

In Seattle, the average seawater temperature in May is 46.6°F (8.1°C). Swimming in 46.6°F (8.1°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

How many hours of daylight does Seattle have in May?

The average day length in May in Seattle is 15h and 10min.

When are sunrise and sunset in May in Seattle?

In May, on the first day of the month, sunrise is at 5:51 am and sunset at 8:21 pm. On the last day of the month, sunrise is at 5:16 am and sunset at 8:57 pm PDT.

How long on average sun shines in May in Seattle?

In May, the average sunshine duration in Seattle, Washington, is 9.2h.

How high is the UV index in May in Seattle?

In May, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a medium hazard to health from exposure to the Sun's 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
Seattle, WA

Average temperature in May - Seattle, WA
  • Average high temperature in May: 64.8°F

The warmest month (with the highest average high temperature) is August (76.3°F).
The month with the lowest average high temperature is December (43.7°F).

  • Average low temperature in May: 44.8°F

The month with the highest average low temperature is August (54°F).
The coldest month (with the lowest average low temperature) is December (35.1°F).

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Average pressure in May
Seattle, WA

Average pressure in May - Seattle, WA
  • Average pressure in May: 30.02"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).

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Average wind speed in May
Seattle, WA

Average wind speed in May - Seattle, WA
  • Average wind speed in May: 4mph

The windiest month (with the highest average wind speed) is March (5.3mph).
The calmest months (with the lowest average wind speed) are July and August (3.5mph).

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Average humidity in May
Seattle, WA

Average humidity in May - Seattle, WA
  • Average humidity in May: 75%

The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is July (69%).

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Average rainfall in May
Seattle, WA

Average rainfall in May - Seattle, WA
  • Average rainfall in May: 0.39"

The wettest month (with the highest rainfall) is December (0.87").
The driest months (with the least rainfall) are July and August (0.12").

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Average rainfall days in May
Seattle, WA

Average rainfall days in May - Seattle, WA
  • Average rainfall days in May: 7 days

The month with the highest number of rainy days is November (9.1 days).
The month with the least rainy days is August (2.8 days).

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Average snowfall in May
Seattle, WA

Average snowfall in May - Seattle, WA
  • Average snowfall in May: 0"

The month with the highest snowfall is February (0.71").
The months with the least snowfall are April, May, June, July, August, September, October and December (0").

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Average snowfall days in May
Seattle, WA

Average snowfall days in May - Seattle, WA
  • Average snowfall days in May: 0 days

The month with the highest number of snowfall days is February (1.9 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average sea temperature in May
Seattle, WA

Average sea temperature in May - Seattle, WA
  • Average sea temperature in May: 46.6°F

The best month for swimming (with the highest average sea temperature) is August (53.5°F).
The coldest month (with the lowest average sea temperature) is February (45.3°F).

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Average daylight in May /
Average sunshine in May
Seattle, WA

Average daylight in May / Average sunshine in May - Seattle, WA
  • Average daylight in May: 15h and 10min

The month with the longest days is June (Average daylight: 15h and 55min).
The month with the shortest days is December (Average daylight: 8h and 31min).

  • Average sunshine in May: 9h and 12min

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 18min).

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Average sunshine days in May
Seattle, WA

Average sunshine days in May - Seattle, WA
  • Average sunshine days in May: 20.3 days

The month with the most sunshine days is August (25.9 days).
The month with the least sunshine days is November (16.8 days).

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Average UV index in May
Seattle, WA

Average UV index in May - Seattle, WA
  • 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
Seattle, WA

Average cloud cover in May - Seattle, WA
  • Average cloud cover in May: 41

The month with the most cloud cover is December (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 25).

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Average visibility in May
Seattle, WA

Average visibility in May - Seattle, WA
  • Average visibility in May: 6mi

The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, November and December (5mi).

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