The best times to visit Union for ideal weather are

June 4th to September 23rd

based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.



Other Union Travel Info

Weather in Union


Average temperatures in Union vary greatly. Considering humidity, temperatures feel cold for about half of the year and otherwise nice with a chance of rain or snow throughout most of the year. The area is less temperate than some — in the 25th percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Union, the hottest months are July, August, and then September. See average monthly temperatures below. The warmest time of year is generally mid August where highs are regularly around 82.3°F (27.9°C) with temperatures rarely dropping below 52.1°F (11.2°C) at night.

Union Temperatures (Fahrenheit)


Union Temperatures (Celsius)


“Feels-Like” Temperatures

The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.

Union Perceived Temperature (F)


Union Perceived Temperature (C)



Average Union Temperatures by Month

Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.

Show Fahrenheit

Month Avg. High (°F) Avg. Mean (°F) Avg. Low (°F)
Jan 45.7 38.8 33
Feb 49.6 40.8 33.7
Mar 53.5 43.2 35.6
Apr 58.6 46.5 36.9
May 66.5 53 42.4
Jun 71.5 58.1 47.8
Jul 79.2 63.1 51.4
Aug 79.2 63 51.5
Sep 73.2 58.6 47.6
Oct 60.9 50.3 41.7
Nov 50.8 42.4 35.1
Dec 44.6 37.9 32

Show Celsius

Month Avg. High (°C) Avg. Mean (°C) Avg. Low (°C)
Jan 7.6 3.8 0.6
Feb 9.8 4.9 0.9
Mar 11.9 6.2 2
Apr 14.8 8.1 2.7
May 19.2 11.7 5.8
Jun 21.9 14.5 8.8
Jul 26.2 17.3 10.8
Aug 26.2 17.2 10.8
Sep 22.9 14.8 8.7
Oct 16.1 10.2 5.4
Nov 10.4 5.8 1.7
Dec 7 3.3 0



Precipitation (Rain or Snow)

If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Union are July, August, and then June. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around early to mid July. For example, on the week of July 9th there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in early to mid March with an average of 4 days of significant precipitation the week of March 12th.

When can you find snow in Union? Weather stations report no annual snow. Please note that a value of 0 for snow in the graph below may either mean there was no snow, or that snow is unreported.

Chance of Precipitation

The graph below shows the % chance of rainy and snowy days in Union.

Days with precipitation

Snow on the Ground

The graph below shows the average snow on the ground in Union (in).

Snow depth

Average Rain and Snow by Month

Show Inches

Month Daily Chance of Rain Average Snow Depth (in) Total Precipitation (in)
Jan 44% 0 8.8
Feb 40% 0 6.3
Mar 51% 0 8.8
Apr 33% 0 4.7
May 22% 0 3.3
Jun 14% 0 1.5
Jul 6% 0 0.9
Aug 10% 0 1.4
Sep 21% 0 3.2
Oct 37% 0 6.8
Nov 47% 0 11.6
Dec 47% 0 11.1

Show Centimeters

Month Daily Chance of Rain Average Snow Depth (cm) Total Precipitation (cm)
Jan 44 0 22.4
Feb 40 0 16
Mar 51 0 22.4
Apr 33 0 11.9
May 22 0 8.4
Jun 14 0 3.8
Jul 6 0 2.3
Aug 10 0 3.6
Sep 21 0 8.1
Oct 37 0 17.3
Nov 47 0 29.5
Dec 47 0 28.2


Humidity and Wind

Union has some extremely humid months, and above average humidity throughout the year. The least humid month is July (61.4% relative humidity), and the most humid month is January (85.3%).

Wind in Union is usually calm. The windiest month is June, followed by July and May. June’s average wind speed of around 6.6 knots (7.6 MPH or 12.2 KPH) is considered “a light breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in early to mid June where average top sustained speeds reach 15 knots, which is considered a moderate breeze.

Relative Humidity (%)

The graph below shows the average % humidity by month in Union.

Avg. Relative Humidity


The graph below shows wind speed (max and average) in knots.

Max Sustained Wind
Average Daily Wind

Average Wind Speeds

Show Wind Speeds

All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.

Month Avg. Wind Avg. Wind Feel Sustained High Wind High Wind Feel
Jan 4 Light breeze 10.5 Gentle breeze
Feb 4.2 Light breeze 10.9 Gentle breeze
Mar 5 Light breeze 13.2 Gentle breeze
Apr 5.5 Light breeze 13.1 Significant breeze
May 5.9 Light breeze 13.6 Gentle breeze
Jun 6.6 Light breeze 14 Significant breeze
Jul 6.4 Light breeze 13.2 Gentle breeze
Aug 5.9 Light breeze 12.6 Significant breeze
Sep 4.4 Light breeze 11.1 Gentle breeze
Oct 3.6 Barely noticeable 10.2 Gentle breeze
Nov 3.8 Barely noticeable 10.8 Gentle breeze
Dec 3.7 Barely noticeable 10.5 Gentle breeze

Show Relative Humidity by Month

Month Avg. Relative Humidity
Jan 85.3%
Feb 78.6%
Mar 74.9%
Apr 67.2%
May 63.9%
Jun 63.3%
Jul 61.4%
Aug 63.3%
Sep 68.8%
Oct 79.5%
Nov 83.9%
Dec 84.8%


Is it Safe to Travel to Union?

Our best data indicates this area is generally safe. As of Oct 07, 2019 there are no travel advisories or warnings for the United States; exercise normal security precautions. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories. This advisory was last updated on Sep 23, 2019.


The Busiest and Least Crowded Months

The busiest month for tourism in Union, WA, US is August, followed by July and June. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Union in October. Those willing to visit at these times will likely find it the least expensive month.

Estimated Tourism by Month


Most Popular Months to Visit

Tourists Seeking Accommodations

Tourism graph is based on Google searches for services used by tourists relative to the rest of the year. Tourism data for this area is somewhat extrapolated based on nearby areas. Displayed data is calculated relative to the peak, so a score of 52 in October means 52% of the tourists vs. August.



Overall Union Travel Experience by Season

Spring (March through May)

Humidity and temperatures combine to make this season feel moderately cold. Highs range from 70°F (21.1°C) and 50.4°F (10.2°C) with warmer temperatures in the later months. Rain is very common with 7 to 16 days of significant precipitation per month. Spring is the second busiest for tourism, which makes it a good time for those looking for things to do.

Summer (June through August)

The middle-year months have comfortably cool weather with high temperatures that are comfortable. These months see the least precipitation with 2 to 4 days of precipitation per month. June – August is the busiest season for tourism in Union, so lodging and other accommodations may cost more than usual.

Fall (September through November)

Fall daily highs range from 77.1°F (25.1°C) and 47.6°F (8.7°C), which will feel chilly given the humidity and wind. It rains or snows a good amount: 6 to 14 days per month. Tourism is the slowest during these months due to the weather, so hotels may be affordably priced.

Winter (December through February)

Weather is too cold this time of year in Union to be enjoyable for warm weather travelers. The average high during this season is between 50.7°F (10.4°C) and 43.5°F (6.4°C). On average, it rains or snows a very great amount: 11 to 15 times per month. These times of year are fairly slow with tourists.


Best Times to Travelthe United States › Union, WA, US