Climate and monthly weather forecast
Index, WA

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Weather in January

January, the same as December, is another cold winter month in Index, Washington, with an average temperature fluctuating between 39.9°F (4.4°C) and 29.7°F (-1.3°C). Index's transition from December to January introduces an average high-temperature of a still icy 39.9°F (4.4°C), marking an insignificant variation from the 38.3°F (3.5°C). Weather in January »

Weather in February

February, the last month of the winter in Index, is another cold month, with an average temperature ranging between min 29.3°F (-1.5°C) and max 40.6°F (4.8°C). As February unfolds, the average high-temperature reaches a still wintry 40.6°F (4.8°C), hinting at a slight fluctuation from the previous month. Weather in February »

Weather in March

March, the first month of the spring in Index, is a chilly month, with an average temperature varying between 45.1°F (7.3°C) and 31.5°F (-0.3°C). The beginning of March records an average high-temperature of a frosty 45.1°F (7.3°C), almost echoing the conditions of the previous month. Weather in March »

Weather in April

April is a fresh spring month in Index, Washington, with an average temperature varying between 51.1°F (10.6°C) and 34.7°F (1.5°C). In April, the average high-temperature marginally rises from a frosty 45.1°F (7.3°C) in March to a cool 51.1°F (10.6°C). Weather in April »

Weather in May

May, the last month of the spring in Index, is a refreshing month, with an average temperature fluctuating between 40.1°F (4.5°C) and 60.4°F (15.8°C). The shift into May is accompanied by a temperature increase, with the average high-temperature rising from a cool 51.1°F (10.6°C) in April to a refreshing 60.4°F (15.8°C). Weather in May »

Weather in June

June, the first month of the summer in Index, is an enjoyable month, with an average temperature varying between 64.9°F (18.3°C) and 43°F (6.1°C). Index's entry into June measures an average high-temperature of a comfortable 64.9°F (18.3°C), closely parallel to the preceding month. Weather in June »

Weather in July

July in Index, Washington, is an agreeable summer month, with an average temperature ranging between max 72.9°F (22.7°C) and min 46.6°F (8.1°C). With the onset of July, Index's weather sees a minor temperature rise, transitioning from a comfortable 64.9°F (18.3°C) in June to an agreeable 72.9°F (22.7°C). Weather in July »

Weather in August

The last month of the summer, August, is a warm month in Index, Washington, with an average temperature fluctuating between 48°F (8.9°C) and 73.4°F (23°C). Temperature records mark August as the warmest month, with highs averaging 73.4°F (23°C) and lows at 48°F (8.9°C). Weather in August »

Weather in September

September, the first month of the autumn in Index, is still a refreshing month, with an average temperature ranging between max 66.4°F (19.1°C) and min 45°F (7.2°C). The transition to September results in a modest reduction in average high-temperature, moving from a moderately hot 73.4°F (23°C) in August to an enjoyable 66.4°F (19.1°C). Weather in September »

Weather in October

October, the same as September, is a cool autumn month in Index, Washington, with an average temperature fluctuating between 54.5°F (12.5°C) and 40.1°F (4.5°C). The transition into October involves a decrease in the average high-temperature, falling from a refreshing 66.4°F (19.1°C) in September to a cool 54.5°F (12.5°C). Weather in October »

Weather in November

November, the last month of the autumn in Index, is also a frosty month, with an average temperature varying between 44.6°F (7°C) and 34.3°F (1.3°C). November shows a mild decline in the average high-temperature, falling from October's cool 54.5°F (12.5°C) to a chilly 44.6°F (7°C). Weather in November »

Weather in December

December, the first month of the winter in Index, is still a cold month, with temperature in the range of an average high of 38.3°F (3.5°C) and an average low of 28.6°F (-1.9°C). December, with its average high-temperature of 38.3°F (3.5°C) and an average low-temperature of 28.6°F (-1.9°C), holds the record as the coldest month. Weather in December »
Updated: Feb 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the most humid month in Index?

The months with the highest humidity are January through March, with an average relative humidity of 88%.

What is the wettest month in Index?

The month with the most rainfall is January, when the rain falls for 19.5 days and typically aggregates up to 7.8" (198mm) of precipitation.

How many days does it rain in Index?

Throughout the year, there are 200.6 rainfall days, and 51.65" (1312mm) of precipitation is accumulated.

When does it snow in Index?

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

How much does it snow in Index?

In Index, during the entire year, snow falls for 15.9 days and aggregates up to 14.41" (366mm) of snow.

What are the months with the least sunshine in Index?

January and December, with an average of 3.7h of sunshine, are months with the least sunshine in Index, Washington.

What are the months with the lowest UV index in Index?

January through April, October through December, with an average maximum UV index of 2, are months with the lowest UV index in Index.

When does it snow the most in Index?

February is the month with the most snowfall in Index. Snow falls for 5.2 days and accumulates 5.43" (138mm) of snow.

When is Daylight Saving Time (DST) in Index?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Index, 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 Index?

May through October are months without snowfall.

When are the longest days in Index?

With an average of 16h and 0min of daylight, June has the longest days of the year in Index, Washington.

What is the least humid month in Index?

July is the least humid month, with an average relative humidity of 72%.

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

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

What month is the hottest in Index?

In Index, August is the warmest month, with temperatures averaging a high of 73.4°F (23°C) and a low of 48°F (8.9°C).

What is the driest month in Index?

The month with the least rainfall is August, when the rain falls for 7.9 days and typically collects 0.79" (20mm) of precipitation.

What month has the most sunshine in Index?

August has the most sunshine of the year, with an average of 10.4h of sunshine.

What is the coldest month in Index?

With its average high temperature of 38.3°F (3.5°C) and a low of 28.6°F (-1.9°C), December is regarded as the coldest month in Index, Washington.

What is the month with the shortest days in Index?

The month with the shortest days in Index is December, with an average of 8h and 30min of daylight.

Average temperature
Index, WA

Average temperature - Index, WA

The warmest month (with the highest average high temperature) is August (73.4°F).
The month with the lowest average high temperature is December (38.3°F).

The month with the highest average low temperature is August (48°F).
The coldest month (with the lowest average low temperature) is December (28.6°F).

Average pressure
Index, WA

Average pressure - Index, WA

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is August (29.99"Hg).

Average wind speed
Index, WA

Average wind speed - Index, WA

The windiest month (with the highest average wind speed) is January (4.8mph).
The calmest month (with the lowest average wind speed) is August (3.2mph).

Average humidity
Index, WA

Average humidity - Index, WA

The months with the highest relative humidity are January, February and March (88%).
The month with the lowest relative humidity is July (72%).

Average rainfall
Index, WA

Average rainfall - Index, WA

The wettest month (with the highest rainfall) is January (7.8").
The driest month (with the least rainfall) is August (0.79").

Average rainfall days
Index, WA

Average rainfall days - Index, WA

The month with the highest number of rainy days is March (22.3 days).
The month with the least rainy days is August (7.9 days).

Average snowfall
Index, WA

Average snowfall - Index, WA

The month with the highest snowfall is February (5.43").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days
Index, WA

Average snowfall days - Index, WA

The month with the highest number of snowfall days is February (5.2 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight / Average sunshine
Index, WA

Average daylight / Average sunshine - Index, WA

The month with the longest days is June (Average daylight: 16h and 0min).
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 24min).
The months with the least sunshine are January and December (Average sunshine: 3h and 42min).

Average sunshine days
Index, WA

Average sunshine days - Index, WA

The month with the most sunshine days is August (19.9 days).
The month with the least sunshine days is March (7 days).

Average UV index
Index, WA

Average UV index - Index, WA

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

Average visibility
Index, WA

Average visibility - Index, WA

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

Index, Washington, USA

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