May weather forecast
Union, WA

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Weather in May

The last month of the spring, May, is a refreshing month in Union, Washington, with an average temperature fluctuating between 41.4°F (5.2°C) and 63.9°F (17.7°C).

Temperature

May indicates a change in the average high-temperature, moving up from a cool 54.9°F (12.7°C) in April to a refreshing 63.9°F (17.7°C). With the onset of night in May, Union reveals a significant decrease in temperature, averaging at an icy 41.4°F (5.2°C).

Humidity

The average relative humidity in May in Union, Washington, is 78%.

Rainfall

In Union, during May, the rain falls for 14.3 days and regularly aggregates up to 1.97" (50mm) of precipitation. Throughout the year, in Union, there are 185.4 rainfall days, and 42.87" (1089mm) of precipitation is accumulated.

Snowfall

In Union, Washington, snow does not fall in April through October.

Daylight

In Union, the average length of the day in May is 15h and 8min.
On the first day of the month, sunrise is at 5:54 am and sunset at 8:24 pm. On the last day of May, sunrise is at 5:19 am and sunset at 9:00 pm PDT.

Sunshine

In May, the average sunshine in Union is 8.9h.

UV index

In Union, the average daily maximum UV index in May is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A daily maximum UV index of 4 in May translates into the following instructions:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. The Sun's radiation is especially intense around midday; try to stay in shade during this period. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.
Updated: Feb 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are May temperatures in Union?

An average high-temperature, in May, in Union, is 63.9°F (17.7°C) and the average low-temperature is 41.4°F (5.2°C).

What is the average humidity in May in Union?

In Union, Washington, the average relative humidity in May is 78%.

How many days does it rain in May in Union?

In May, in Union, the rain falls for 14.3 days. Throughout May, 1.97" (50mm) of precipitation is accumulated.

When it does not snow in Union?

In Union, Washington, snow does not fall in April through October.

How many hours of daylight does Union have in May?

The average day length in May is 15h and 8min.

When are sunrise and sunset in May in Union?

In May, on the first day of the month, sunrise is at 5:54 am and sunset at 8:24 pm. On the last day of the month, in Union, Washington, sunrise is at 5:19 am and sunset at 9:00 pm PDT.

How long on average sun shines in May in Union?

The average sunshine duration in May in Union, Washington, is 8.9h.

What is the UV index intensity in May in Union?

In May, the average daily maximum UV index in Union, Washington, is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Union, WA

Average temperature in May - Union, WA
  • Average high temperature in May: 63.9°F

The warmest month (with the highest average high temperature) is August (76.6°F).
The month with the lowest average high temperature is December (41.5°F).

  • Average low temperature in May: 41.4°F

The month with the highest average low temperature is August (50.4°F).
The coldest month (with the lowest average low temperature) is February (32.7°F).

Average pressure in May
Union, WA

Average pressure in May - Union, WA
  • Average pressure in May: 30.04"Hg

The month with the highest atmospheric pressure is January (30.08"Hg).
The month with the lowest atmospheric pressure is March (30.01"Hg).

Average wind speed in May
Union, WA

Average wind speed in May - Union, WA
  • Average wind speed in May: 3.9mph

The windiest month (with the highest average wind speed) is March (4.3mph).
The calmest month (with the lowest average wind speed) is September (3.4mph).

Average humidity in May
Union, WA

Average humidity in May - Union, WA
  • Average humidity in May: 78%

The months with the highest relative humidity are November and December (90%).
The month with the lowest relative humidity is July (72%).

Average rainfall in May
Union, WA

Average rainfall in May - Union, WA
  • Average rainfall in May: 1.97"

The wettest month (with the highest rainfall) is January (7.24").
The driest month (with the least rainfall) is July (0.43").

Average rainfall days in May
Union, WA

Average rainfall days in May - Union, WA
  • Average rainfall days in May: 14.3 days

The month with the highest number of rainy days is March (21.4 days).
The month with the least rainy days is August (6.3 days).

Average snowfall in May
Union, WA

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

The month with the highest snowfall is February (2.17").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in May
Union, WA

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

The month with the highest number of snowfall days is February (3.3 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
Union, WA

Average daylight in May / Average sunshine in May - Union, WA
  • Average daylight in May: 15h and 1min

The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in May: 8h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 3h and 30min).

Average sunshine days in May
Union, WA

Average sunshine days in May - Union, WA
  • Average sunshine days in May: 14.3 days

The month with the most sunshine days is July (21.7 days).
The month with the least sunshine days is March (7.5 days).

Average UV index in May
Union, WA

Average UV index in May - Union, WA
  • Average UV index in May: 4

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in May
Union, WA

Average cloud cover in May - Union, WA
  • Average cloud cover in May: 47

The months with the most cloud cover are January and December (Cloud cover 64).
The months with the least cloud cover are July and August (Cloud cover 30).

Average visibility in May
Union, WA

Average visibility in May - Union, WA
  • Average visibility in May: 4mi

The months with the highest visibility are June, July, August and September (5mi).
The months with the lowest visibility are January, February, March, April, May, October, November and December (4mi).

Union, Washington, USA

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