Climate and monthly weather forecast
Issaquah, WA

Weather in January

January in Issaquah, Washington, is a chilly winter month, with temperature in the range of an average low of 34.3°F (1.3°C) and an average high of 44.2°F (6.8°C). In Issaquah, the average high-temperature in January is essentially the same as in December - a chilly 44.2°F (6.8°C). Weather in January »

Weather in February

The last month of the winter, February, is another chilly month in Issaquah, Washington, with an average temperature ranging between max 45.1°F (7.3°C) and min 33.4°F (0.8°C). In Issaquah, the average high-temperature in February is practically the same as in January - a still frosty 45.1°F (7.3°C). Weather in February »

Weather in March

March, the first month of the spring in Issaquah, is a cool month, with an average temperature ranging between max 50°F (10°C) and min 35.4°F (1.9°C). In Issaquah, Washington, the average high-temperature in March is essentially the same as in February - a fresh 50°F (10°C). Weather in March »

Weather in April

April in Issaquah, Washington, is a mild spring month, with an average temperature varying between 55.9°F (13.3°C) and 37.9°F (3.3°C). In Issaquah, Washington, the average high-temperature in April slightly increases from a cool 50°F (10°C) in March to a moderate 55.9°F (13.3°C). Weather in April »

Weather in May

The last month of the spring, May, is a comfortable month in Issaquah, Washington, with temperature in the range of an average high of 64.6°F (18.1°C) and an average low of 42.4°F (5.8°C). In Issaquah, Washington, the average high-temperature in May slightly increases from a mild 55.9°F (13.3°C) in April to an enjoyable 64.6°F (18.1°C). Weather in May »

Weather in June

June, the first month of the summer in Issaquah, is an agreeable month, with an average temperature varying between 45.7°F (7.6°C) and 69.4°F (20.8°C). In Issaquah, the average high-temperature in June is practically the same as in May - a pleasant 69.4°F (20.8°C). Weather in June »

Weather in July

July is a warm summer month in Issaquah, Washington, with an average temperature fluctuating between 50°F (10°C) and 76.1°F (24.5°C). In July, the average high-temperature slightly increases from an agreeable 69.4°F (20.8°C) in June to a warm 76.1°F (24.5°C). Weather in July »

Weather in August

August, the last month of the summer in Issaquah, is another warm month, with an average temperature fluctuating between 77°F (25°C) and 51.4°F (10.8°C). With an average high-temperature of 77°F (25°C) and an average low-temperature of 51.4°F (10.8°C), August is the warmest month. Weather in August »

Weather in September

The first month of the autumn, September, is also an agreeable month in Issaquah, Washington, with an average temperature fluctuating between 48.4°F (9.1°C) and 70°F (21.1°C). In Issaquah, the average high-temperature in September marginally drops from a moderately hot 77°F (25°C) in August to a pleasant 70°F (21.1°C). Weather in September »

Weather in October

October, the same as September, in Issaquah, Washington, is a moderate autumn month, with temperature in the range of an average low of 43.7°F (6.5°C) and an average high of 58.6°F (14.8°C). In October, the average high-temperature drops from a pleasant 70°F (21.1°C) in September to a moderate 58.6°F (14.8°C). Weather in October »

Weather in November

November, the last month of the autumn in Issaquah, is also a frosty month, with an average temperature ranging between max 48.4°F (9.1°C) and min 38.1°F (3.4°C). In Issaquah, the average high-temperature in November drops from a mild 58.6°F (14.8°C) in October to a frosty 48.4°F (9.1°C). Weather in November »

Weather in December

December, the first month of the winter in Issaquah, is also a wintry month, with an average temperature varying between 42.3°F (5.7°C) and 33.4°F (0.8°C). The coldest month is December, with an average high-temperature of 42.3°F (5.7°C) and an average low-temperature of 33.4°F (0.8°C). Weather in December »
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FAQ

What are the most humid months in Issaquah?

The months with the highest humidity are January and February, with an average relative humidity of 85%.

How much does it rain in Issaquah?

In Issaquah, Washington, during the entire year, the rain falls for 127.4 days and collects up to 12.52" (318mm) of precipitation.

When does it snow in Issaquah?

January through April, November and December are months with snowfall in Issaquah, Washington.

How much does it snow in Issaquah?

In Issaquah, Washington, during the entire year, snow falls for 5.9 days and aggregates up to 1.93" (49mm) of snow.

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

The months with the lowest UV index in Issaquah, Washington, are January, February, November and December, with an average maximum UV index of 2.

When does it snow the most in Issaquah?

The month with the most snowfall in Issaquah, Washington, is February, when snow falls for 2.5 days and typically aggregates up to 0.94" (24mm) of snow.

When is Daylight Saving Time (DST) in Issaquah?

On Sunday, March 12. 2023, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 5. 2023, at 2:00 am, and the time zone reverts from PDT to PST.

When it does not snow in Issaquah?

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

When are the longest days in Issaquah?

With an average of 15h and 55min of daylight, June has the longest days of the year in Issaquah.

What is the least humid month in Issaquah?

The least humid month in Issaquah, Washington, is July, with an average relative humidity of 69%.

What is the driest month in Issaquah?

The month with the least rainfall is July, when the rain falls for 4.9 days and typically collects 0.24" (6mm) of precipitation.

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

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

What is the warmest month in Issaquah?

August is the warmest month, with an average high-temperature of 77°F (25°C) and an average low-temperature of 51.4°F (10.8°C).

What month has the most sunshine in Issaquah?

With an average of 10.5h of sunshine, August has the most sunshine of the year in Issaquah.

What is the coldest month in Issaquah?

The coldest month in Issaquah is December, with an average high-temperature of 42.3°F (5.7°C) and an average low-temperature of 33.4°F (0.8°C).

What is the wettest month in Issaquah?

The month with the most rainfall in Issaquah, Washington, is December, when the rain falls for 13.7 days and typically aggregates up to 2.01" (51mm) of precipitation.

What is the month with the shortest days in Issaquah?

With an average of 8h and 31min of daylight, December has the shortest days of the year in Issaquah, Washington.

What is the month with the least sunshine in Issaquah?

December has the least sunshine of the year in Issaquah, with an average of 4h of sunshine.

Average temperature
Issaquah, WA

Average temperature - Issaquah, WA

The warmest month (with the highest average high temperature) is August (77°F).
The month with the lowest average high temperature is December (42.3°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 (33.4°F).

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Average pressure
Issaquah, WA

Average pressure - Issaquah, WA

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).

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Average wind speed
Issaquah, WA

Average wind speed - Issaquah, WA

The windiest month (with the highest average wind speed) is January (5.1mph).
The calmest month (with the lowest average wind speed) is August (3.4mph).

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Average humidity
Issaquah, WA

Average humidity - Issaquah, WA

The months with the highest relative humidity are January and February (85%).
The month with the lowest relative humidity is July (69%).

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Average rainfall
Issaquah, WA

Average rainfall - Issaquah, WA

The wettest month (with the highest rainfall) is December (2.01").
The driest month (with the least rainfall) is July (0.24").

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Average rainfall days
Issaquah, WA

Average rainfall days - Issaquah, WA

The month with the highest number of rainy days is March (14.8 days).
The month with the least rainy days is August (4.3 days).

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Average snowfall
Issaquah, WA

Average snowfall - Issaquah, WA

The month with the highest snowfall is February (0.94").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days
Issaquah, WA

Average snowfall days - Issaquah, WA

The month with the highest number of snowfall days is February (2.5 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
Issaquah, WA

Average daylight / Average sunshine - Issaquah, WA

The month with the longest days is June (Average daylight: 15h and 55min).
The month with the shortest days is December (Average daylight: 8h and 31min).

The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is December (Average sunshine: 4h and 0min).

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Average sunshine days
Issaquah, WA

Average sunshine days - Issaquah, WA

The month with the most sunshine days is August (25 days).
The month with the least sunshine days is February (12.9 days).

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Average UV index
Issaquah, WA

Average UV index - Issaquah, 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 2).

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Average visibility
Issaquah, WA

Average visibility - Issaquah, WA

The months with the highest visibility are July and August (6mi).
The months with the lowest visibility are January, February and December (4mi).

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