Climate and monthly weather forecast
Sumas, WA

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Weather in January

January, the same as December, is another cold winter month in Sumas, Washington, with an average temperature fluctuating between 41.2°F (5.1°C) and 32.9°F (0.5°C). Sumas's average high-temperature in January is a still wintry 41.2°F (5.1°C), indicating a subtle variation from December. Weather in January »

Weather in February

February, the last month of the winter in Sumas, is also a wintry month, with an average temperature ranging between min 31.6°F (-0.2°C) and max 42.3°F (5.7°C). The average high-temperature during February registers at a still icy 42.3°F (5.7°C), maintaining a close resemblance to the previous month. Weather in February »

Weather in March

The first month of the spring, March, is a frosty month in Sumas, Washington, with an average temperature ranging between max 47.1°F (8.4°C) and min 34.9°F (1.6°C). Sumas records an average high-temperature of a frosty 47.1°F (8.4°C) as March arrives, nearly mirroring the previous month's climate. Weather in March »

Weather in April

April is a cool spring month in Sumas, Washington, with temperature in the range of an average high of 54°F (12.2°C) and an average low of 38.1°F (3.4°C). April's arrival coincides with a marginal rise in the average high-temperature, moving from March's chilly 47.1°F (8.4°C) to a fresh 54°F (12.2°C). Weather in April »

Weather in May

May, the last month of the spring in Sumas, is a comfortable month, with an average temperature fluctuating between 62.6°F (17°C) and 43°F (6.1°C). As April gives way to May, the average high-temperature displays a slight ascent, adjusting from a cool 54°F (12.2°C) to a refreshing 62.6°F (17°C). Weather in May »

Weather in June

June, the first month of the summer in Sumas, is still a comfortable month, with temperature in the range of an average low of 46°F (7.8°C) and an average high of 66.2°F (19°C). The onset of June marks an average high-temperature of a still refreshing 66.2°F (19°C), hardly differing from May's 62.6°F (17°C). Weather in June »

Weather in July

July in Sumas, Washington, is an agreeable summer month, with an average temperature ranging between min 49.6°F (9.8°C) and max 73°F (22.8°C). July's arrival coincides with a subtle temperature rise, moving from June's comfortable 66.2°F (19°C) to a pleasant 73°F (22.8°C). Weather in July »

Weather in August

The last month of the summer, August, is a warm month in Sumas, Washington, with temperature in the range of an average high of 73.6°F (23.1°C) and an average low of 51.4°F (10.8°C). August is the month that records the highest temperatures, with averages ranging from a high of 73.6°F (23.1°C) to a low of 51.4°F (10.8°C). Weather in August »

Weather in September

September, the first month of the autumn in Sumas, is also an enjoyable month, with an average temperature fluctuating between 47.5°F (8.6°C) and 66.7°F (19.3°C). In Sumas, the beginning of September is marked by a marginally lowered average high-temperature, shifting from August's moderately hot 73.6°F (23.1°C) to an enjoyable 66.7°F (19.3°C). Weather in September »

Weather in October

October, the same as September, in Sumas, Washington, is another refreshing autumn month, with an average temperature fluctuating between 42.3°F (5.7°C) and 56.1°F (13.4°C). During the transition into October, Sumas observes a decrease in the average high-temperature, falling from a comfortable 66.7°F (19.3°C) in September to a still refreshing 56.1°F (13.4°C). Weather in October »

Weather in November

The last month of the autumn, November, is another chilly month in Sumas, Washington, with temperature in the range of an average high of 45.7°F (7.6°C) and an average low of 36.5°F (2.5°C). The onset of November comes with a shift in the average high-temperature, falling from a refreshing 56.1°F (13.4°C) in October to a frosty 45.7°F (7.6°C). Weather in November »

Weather in December

The first month of the winter, December, is still a cold month in Sumas, Washington, with an average temperature ranging between min 31.6°F (-0.2°C) and max 39.6°F (4.2°C). December, noted for its average high-temperature of 39.6°F (4.2°C) and an average low-temperature of 31.6°F (-0.2°C), is considered the coldest month. Weather in December »
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Frequently asked questions

What is the most humid month in Sumas?

January is the most humid month in Sumas, with an average relative humidity of 87%.

How many days does it rain in Sumas?

Throughout the year, in Sumas, there are 188 rainfall days, and 49.88" (1267mm) of precipitation is accumulated.

When does it snow in Sumas?

Months with snowfall in Sumas, Washington, are January through April, November and December.

How much does it snow in Sumas?

Throughout the year, in Sumas, there are 14.7 snowfall days, and 10.2" (259mm) of snow is accumulated.

What is the month with the lowest UV index in Sumas?

January, February, October through December, with an average maximum UV index of 2, are months with the lowest UV index in Sumas, Washington.

What is the snowiest month in Sumas?

February is the month with the most snowfall. Snow falls for 4.7 days and accumulates 3.11" (79mm) of snow.

When is Daylight Saving Time (DST) in Sumas?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Sumas, Washington, 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 it does not snow in Sumas?

In Sumas, Washington, snow does not fall in May through October.

When are the longest days in Sumas?

With an average of 16h and 6min of daylight, June has the longest days of the year in Sumas.

What is the least humid month in Sumas?

With an average relative humidity of 73%, July is the least humid month.

What is the driest month in Sumas?

July is the month with the least rainfall in Sumas. Rain falls for 8.3 days and accumulates 0.91" (23mm) of precipitation.

What is the month with the highest UV index in Sumas?

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

What part of the year is the hottest in Sumas?

Sumas's temperature records reveal August as the warmest month, marked by average highs of 73.6°F (23.1°C) and lows of 51.4°F (10.8°C).

What month has the most sunshine in Sumas?

The month with the most sunshine in Sumas, Washington, is August, with an average of 10.3h of sunshine.

What is the wettest month in Sumas?

The month with the most rainfall in Sumas, Washington, is November, when the rain falls for 20.2 days and typically aggregates up to 7.72" (196mm) of precipitation.

What is the coldest time of year in Sumas?

December is the month when Sumas, Washington, experiences its coldest temperatures, averaging a high of 39.6°F (4.2°C) and a low of 31.6°F (-0.2°C).

What is the month with the shortest days in Sumas?

With an average of 8h and 18min of daylight, December has the shortest days of the year in Sumas.

What is the month with the least sunshine in Sumas?

December has the least sunshine of the year, with an average of 3.8h of sunshine.

Average temperature
Sumas, WA

Average temperature - Sumas, WA

The warmest month (with the highest average high temperature) is August (73.6°F).
The month with the lowest average high temperature is December (39.6°F).

The month with the highest average low temperature is August (51.4°F).
The coldest months (with the lowest average low temperature) are February and December (31.6°F).

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Average pressure
Sumas, WA

Average pressure - Sumas, WA

The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March and August (30"Hg).

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Average wind speed
Sumas, WA

Average wind speed - Sumas, WA

The windiest months (with the highest average wind speed) are January and February (4.7mph).
The calmest month (with the lowest average wind speed) is August (3.2mph).

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Average rainfall
Sumas, WA

Average rainfall - Sumas, WA

The wettest month (with the highest rainfall) is November (7.72").
The driest month (with the least rainfall) is July (0.91").

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Average rainfall days
Sumas, WA

Average rainfall days - Sumas, WA

The month with the highest number of rainy days is March (20.5 days).
The month with the least rainy days is August (7.8 days).

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Average snowfall
Sumas, WA

Average snowfall - Sumas, WA

The month with the highest snowfall is February (3.11").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days
Sumas, WA

Average snowfall days - Sumas, WA

The month with the highest number of snowfall days is February (4.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight / Average sunshine
Sumas, WA

Average daylight / Average sunshine - Sumas, WA

The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 18min).

The month with the most sunshine is August (Average sunshine: 10h and 18min).
The month with the least sunshine is December (Average sunshine: 3h and 48min).

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Average sunshine days
Sumas, WA

Average sunshine days - Sumas, WA

The months with the most sunshine days are July and August (21 days).
The month with the least sunshine days is March (8.4 days).

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Average UV index
Sumas, WA

Average UV index - Sumas, WA

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

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Average visibility
Sumas, WA

Average visibility - Sumas, WA

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

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Sumas, Washington, USA

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