Climate and monthly weather forecast
Snoqualmie Pass, WA

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The climate of Snoqualmie Pass

Snoqualmie Pass, Washington, USA, presents a Mediterranean climatic condition with warm summers, as characterized by the Köppen climate classification Csb. Nestled in the heart of the Cascade Mountain Range, the pass experiences distinct climatic patterns throughout the year. Variations in temperature, precipitation, snowfall, and other climatic factors shape the weather conditions every month.

Temperature swings are noticeable between the warmest and coldest months. The highest temperatures are observed around July and August, with average highs peaking around 70.3°F (21.3°C) to 71.2°F (21.8°C). Conversely, the winter months of December and January witness the lowest temperatures that range from 20.3°F (-6.5°C) to 21.4°F (-5.9°C). Humidity levels fluctuate from a high of 93% in January to a low of 69% in July.

Precipitation amounts also vary, with December registering the maximum rainfall of 4.02" (102mm), while July sees the minimum at 0.51" (13mm). Surprisingly, the highest number of rainfall days is not in the wettest month, but rather in May with 15.7 days. The most snowfall occurs in January and December with up to 27.72" (704mm) and 27.24" (692mm) respectively. Sunlight duration is longest in the summer with up to 15.9 hours in June and shortest in winter, declining to 8.5 hours by December.

The best time to visit Snoqualmie Pass

Considering the climatic conditions, visitors might find the summer months from June to August most appealing. During this period, the daytime temperatures ascend to a comfortable level between 60.4°F (15.8°C) to 71.2°F (21.8°C). The rainiest days subside, leading to fewer rainfall days, from 9.1 in July to 7.2 in August. Longer daylight periods persist during these months, providing ample sunshine for outdoor activities. July stands out with the highest sunlight duration of 10.7 hours and the maximum UV index, making it the brightest month of the year.

The worst time to visit Snoqualmie Pass

The challenging weather conditions pose a discouragement for tourists during the winter months of December and January. Extreme cold reigns as temperatures plunge to a numbing low between 20.3°F (-6.5°C) to 21.4°F (-5.9°C). Moreover, these two months experience the most snowfall with 27.72" (704mm) in December and 27.24" (692mm) in January. Consequently, roads might be blocked, imposing a significant obstacle for travelers.

Spring weather in Snoqualmie Pass

Springtime, running from March through May, presents rising temperatures in Snoqualmie Pass. The warmth climbs from 37°F (2.8°C) in March to a more temperate 54.7°F (12.6°C) in May. Rainfall tends to decline during this season, with the wettest March recording 3.07" (78mm), decreasing to 1.93" (49mm) by May. Snowfall confines itself to March and April, absent entirely by May.

Summer weather in Snoqualmie Pass

Summer, which extends from June to August, ushers in the best weather for Snoqualmie Pass. Daylight hours peak at up to 15.9 hours in June, facilitating the bright, warm day conditions. Average temperatures during these months prevail between 60.4°F (15.8°C) and 71.2°F (21.8°C). The precipitation is relatively low, leaving only a minimal amount of rainfall to freshen up the summer days.

Autumn weather in Snoqualmie Pass

Autumn sets in from September to November, marked by a gradual decrease in temperatures starting from 62.1°F (16.7°C) in September to 30.2°F (-1°C) by November. The onset of rain becomes apparent with September recording 1.06" (27mm) of rain, which escalates to 2.91" (74mm) by November. The return of snow indicates the winter around the corner, with November seeing a significant increase in snowfall to 13.5" (343mm).

Winter weather in Snoqualmie Pass

December to February are the coldest months in Snoqualmie Pass, marked by icy averages that fluctuate from 21.4°F (-5.9°C) in February to 32°F (0°C) in December. Snowfall reaches its peak during these months, creating a winter wonderland but posing a challenge for travel. The short daylight hours during winter, in combination with the high humidity, heighten the chill in the air further.

Weather in January

Characteristic of weather patterns in Snoqualmie Pass, Washington, in January indicates a blend of low mercury levels and high snowfall. The temperatures attain their nadir, posting an average high of 32°F (0°C) and a low of 21.4°F (-5.9°C). Weather in January »

Weather in February

February weather in Washington's Snoqualmie Pass presents patterns resembling the previous month, January, with marginally higher temperatures. Snowfall quantities decrease slightly from January, but the city continues to be a winter wonderland. Weather in February »

Weather in March

In March, Snoqualmie Pass ushers in subtle hints of spring. In a break from the prolonged chills, there is a rise in temperatures. The snowfall is still significant, but it shows a decrease from the winter peak of January and February. Weather in March »

Weather in April

Overlaying a transitional weather pattern, April in Snoqualmie Pass, Washington, denotes the onset of milder temperatures and lesser snowfall. Residents find relief from the biting cold, as average lows rise to 29.3°F (-1.5°C) and the highs reach 43.7°F (6.5°C), marking the end of freezing temperatures. Weather in April »

Weather in May

May in Snoqualmie Pass marks a noticeable departure from the colder months as spring gets into full swing. The weather shift is evident where nature comes alive, and outdoor activities gain traction. As temperatures rise, the snowfall finally takes a back seat, replaced by rainfall. Weather in May »

Weather in June

Weather in Snoqualmie Pass in June signifies the real onset of the warmer season. It is a favorable time for outdoor pursuits as nature blooms in its full grandeur. Witnessing a jump in temperatures, it also marks a month with considerable hours of sunshine. Weather in June »

Weather in July

July stands as the yardstick of summer in Snoqualmie Pass, with pleasant weather conditions and soaring temperatures. As temperatures touch their zenith, snowfall becomes a rarity and increased daylight marks longer summer days. The city comes alive with activities, as the green landscapes bask under the ample sunlight. Weather in July »

Weather in August

August weather in Snoqualmie Pass carries forward the dominion of summer, closely resembling the pattern of July. It continues the trend of high temperatures, sustained sunshine and negligible snowfall. The city doesn't lose its summer flair, hosting numerous outdoor activities under the clear blue skies. Weather in August »

Weather in September

In September, Snoqualmie Pass, Washington, witnesses a gradual shift from summer to fall. The weather begins to swing, showcasing shorter days and a noticeable plunge in temperatures. The transitional weather brings a slight increase in average rainfall, accompanied by a gradual increase in the degree of humidity. Weather in September »

Weather in October

October in Snoqualmie Pass is the month where Autumn manifests fully. There is a further drop in temperatures, coupled with increased rainfall, making it one of the rainy months of the year. As the fall turns a little more intense, the first traces of snow make their appearance. Weather in October »

Weather in November

November showcases the first signs of winter in Snoqualmie Pass, with temperatures plummeting further. While it still holds onto autumn's vibrancy, the mercury level takes a significant dip. The month is marked by more frequent snowfall, as colorful leaves of autumn give way to the white blanket of winter. Weather in November »

Weather in December

December in Snoqualmie Pass, Washington, is a full-fledged winter month. The winter chill is set at its max with the average high temperature dipping down to 30.2°F (-1°C) and a low plunging down to 20.3°F (-6.5°C). The city is decked in snowflakes, making it a haven for winter sports enthusiasts. Weather in December »
Updated: Jul 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the most humid months?

The months with the highest humidity are January and February, with an average relative humidity of 93%.

What is the wettest month?

January is the month with the most rainfall. Rain falls for 6.8 days and accumulates 4.21" (107mm) of precipitation.

How much does it rain?

In Snoqualmie Pass, during the entire year, the rain falls for 127.9 days and collects up to 28.58" (726mm) of precipitation.

When does it snow?

Months with snowfall are January through June, September through December.

When does it snow the most?

January is the month with the most snowfall. Snow falls for 20.3 days and accumulates 27.72" (704mm) of snow.

How much does it snow?

Throughout the year, in Snoqualmie Pass, there are 135.3 snowfall days, and 134.33" (3412mm) of snow is accumulated.

What are the months with the least sunshine in Snoqualmie Pass?

January and February, with an average of 3h of sunshine, are months with the least sunshine.

What is the month with the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 1.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.

When are the longest days?

The month with the longest days is June, with an average of 15h and 54min of daylight.

What is the least humid month?

July is the least humid month, with an average relative humidity of 69%.

What is the driest month?

The month with the least rainfall is July, when the rain falls for 9.1 days and typically collects 0.51" (13mm) of precipitation.

When it does not snow?

In Snoqualmie Pass, snow does not fall in July and August.

What is the month with the highest UV index?

With an average maximum UV index of 5, July is the month with the highest UV index.

What part of the year is the hottest?

August, recording an average high temperature of 71.2°F (21.8°C) and a low temperature of 45°F (7.2°C), is Snoqualmie Pass's warmest month.

What month has the most sunshine?

With an average of 10.9h of sunshine, August has the most sunshine of the year.

What are the coldest months?

The lowest temperatures are recorded in December, with averages reaching a high of 30.2°F (-1°C) and a low of 20.3°F (-6.5°C).

What is the month with the shortest days?

With an average of 8h and 30min of daylight, December has the shortest days of the year.

Average temperature
Snoqualmie Pass, WA

Average temperature - Snoqualmie Pass, WA

The warmest month (with the highest average high temperature) is August (71.2°F).
The month with the lowest average high temperature is December (30.2°F).

The month with the highest average low temperature is August (45°F).
The coldest month (with the lowest average low temperature) is December (20.3°F).

Average pressure
Snoqualmie Pass, WA

Average pressure - Snoqualmie Pass, WA

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is August (29.97"Hg).

Average wind speed
Snoqualmie Pass, WA

Average wind speed - Snoqualmie Pass, WA

The windiest month (with the highest average wind speed) is January (5mph).
The calmest month (with the lowest average wind speed) is September (3.9mph).

Average humidity
Snoqualmie Pass, WA

Average humidity - Snoqualmie Pass, WA

The months with the highest relative humidity are January and February (93%).
The month with the lowest relative humidity is July (69%).

Average rainfall
Snoqualmie Pass, WA

Average rainfall - Snoqualmie Pass, WA

The wettest month (with the highest rainfall) is January (4.21").
The driest month (with the least rainfall) is July (0.51").

Average rainfall days
Snoqualmie Pass, WA

Average rainfall days - Snoqualmie Pass, WA

The month with the highest number of rainy days is May (15.7 days).
The month with the least rainy days is January (6.8 days).

Average snowfall
Snoqualmie Pass, WA

Average snowfall - Snoqualmie Pass, WA

The month with the highest snowfall is January (27.72").
The months with the least snowfall are July and August (0").

Average snowfall days
Snoqualmie Pass, WA

Average snowfall days - Snoqualmie Pass, WA

The month with the highest number of snowfall days is December (22.3 days).
The months with the least snowfall days are July and August (0 days).

Average daylight / Average sunshine
Snoqualmie Pass, WA

Average daylight / Average sunshine - Snoqualmie Pass, WA

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).

The month with the most sunshine is August (Average sunshine: 10h and 54min).
The months with the least sunshine are January and February (Average sunshine: 3h and 0min).

Average sunshine days
Snoqualmie Pass, WA

Average sunshine days - Snoqualmie Pass, WA

The month with the most sunshine days is August (20.2 days).
The month with the least sunshine days is February (6 days).

Average UV index
Snoqualmie Pass, WA

Average UV index - Snoqualmie Pass, WA

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).

Average visibility
Snoqualmie Pass, WA

Average visibility - Snoqualmie Pass, WA

The months with the highest visibility are June, July and August (5mi).
The months with the lowest visibility are January, February, March and December (3mi).

Snoqualmie Pass, Washington, USA

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