Climate and monthly weather forecastSumas, WA
Climate and monthly weather forecast
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 »Updated: Feb 14, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
January is the most humid month in Sumas, with an average relative humidity of 87%.
Throughout the year, in Sumas, there are 188 rainfall days, and 49.88" (1267mm) of precipitation is accumulated.
Months with snowfall in Sumas, Washington, are January through April, November and December.
Throughout the year, in Sumas, there are 14.7 snowfall days, and 10.2" (259mm) of snow is accumulated.
January, February, October through December, with an average maximum UV index of 2, are months with the lowest UV index in Sumas, Washington.
February is the month with the most snowfall. Snow falls for 4.7 days and accumulates 3.11" (79mm) of snow.
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.
In Sumas, Washington, snow does not fall in May through October.
With an average of 16h and 6min of daylight, June has the longest days of the year in Sumas.
With an average relative humidity of 73%, July is the least humid month.
July is the month with the least rainfall in Sumas. Rain falls for 8.3 days and accumulates 0.91" (23mm) of precipitation.
July is the month with the highest UV index, with an average maximum UV index of 5.
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).
The month with the most sunshine in Sumas, Washington, is August, with an average of 10.3h of sunshine.
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.
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).
With an average of 8h and 18min of daylight, December has the shortest days of the year in Sumas.
December has the least sunshine of the year, with an average of 3.8h of sunshine.
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).
Average pressure
Sumas, WA
- Average pressure in January:
30.09"Hg - Average pressure in February:
30.06"Hg - Average pressure in March:
30"Hg - Average pressure in April:
30.03"Hg - Average pressure in May:
30.01"Hg - Average pressure in June:
30.01"Hg
- Average pressure in July:
30.03"Hg - Average pressure in August:
30"Hg - Average pressure in September:
30.01"Hg - Average pressure in October:
30.03"Hg - Average pressure in November:
30.03"Hg - Average pressure in December:
30.08"Hg
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).
Average wind speed
Sumas, WA
- Average wind speed in January:
4.7mph - Average wind speed in February:
4.7mph - Average wind speed in March:
4.5mph - Average wind speed in April:
4.1mph - Average wind speed in May:
3.6mph - Average wind speed in June:
3.5mph
- Average wind speed in July:
3.5mph - Average wind speed in August:
3.2mph - Average wind speed in September:
3.4mph - Average wind speed in October:
3.9mph - Average wind speed in November:
4.5mph - Average wind speed in December:
4.5mph
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).
Average humidity
Sumas, WA
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is July (73%).
Average rainfall
Sumas, WA
- Average rainfall in January:
7.01" - Average rainfall in February:
4.13" - Average rainfall in March:
5.94" - Average rainfall in April:
3.66" - Average rainfall in May:
2.52" - Average rainfall in June:
1.73"
- Average rainfall in July:
0.91" - Average rainfall in August:
1.18" - Average rainfall in September:
2.87" - Average rainfall in October:
5.35" - Average rainfall in November:
7.72" - Average rainfall in December:
6.85"
The wettest month (with the highest rainfall) is November (7.72").
The driest month (with the least rainfall) is July (0.91").
Average rainfall days
Sumas, WA
- Average rainfall days in January:
18.2 days - Average rainfall days in February:
15.6 days - Average rainfall days in March:
20.5 days - Average rainfall days in April:
18.7 days - Average rainfall days in May:
14.3 days - Average rainfall days in June:
13.6 days
- Average rainfall days in July:
8.3 days - Average rainfall days in August:
7.8 days - Average rainfall days in September:
14.5 days - Average rainfall days in October:
17.1 days - Average rainfall days in November:
20.2 days - Average rainfall days in December:
19.2 days
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).
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").
Average snowfall days
Sumas, WA
- Average snowfall days in January:
2.9 days - Average snowfall days in February:
4.7 days - Average snowfall days in March:
2.6 days - Average snowfall days in April:
0.4 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0 days - Average snowfall days in November:
1.1 days - Average snowfall days in December:
3 days
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).
Average daylight / Average sunshine
Sumas, WA
- Average daylight in January:
8h and 48min - Average daylight in February:
10h and 12min - Average daylight in March:
11h and 54min - Average daylight in April:
13h and 48min - Average daylight in May:
15h and 18min - Average daylight in June:
16h and 6min
- Average daylight in July:
15h and 42min - Average daylight in August:
14h and 18min - Average daylight in September:
12h and 36min - Average daylight in October:
10h and 48min - Average daylight in November:
9h and 12min - Average daylight in December:
8h and 18min
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).
- Average sunshine in January:
3h and 54min - Average sunshine in February:
4h and 0min - Average sunshine in March:
5h and 24min - Average sunshine in April:
7h and 36min - Average sunshine in May:
9h and 0min - Average sunshine in June:
9h and 0min
- Average sunshine in July:
10h and 12min - Average sunshine in August:
10h and 18min - Average sunshine in September:
8h and 48min - Average sunshine in October:
5h and 6min - Average sunshine in November:
4h and 6min - Average sunshine in December:
3h and 48min
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).
Average sunshine days
Sumas, WA
- Average sunshine days in January:
11 days - Average sunshine days in February:
8.8 days - Average sunshine days in March:
8.4 days - Average sunshine days in April:
9.3 days - Average sunshine days in May:
13.3 days - Average sunshine days in June:
13.5 days
- Average sunshine days in July:
21 days - Average sunshine days in August:
21 days - Average sunshine days in September:
14.2 days - Average sunshine days in October:
12.4 days - Average sunshine days in November:
8.8 days - Average sunshine days in December:
10.3 days
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).
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).
Average cloud cover
Sumas, WA
The month with the most cloud cover is March (Cloud cover 60).
The months with the least cloud cover are July and August (Cloud cover 30).
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).
