Climate and monthly weather forecastIndex, WA
Climate and monthly weather forecast
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
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
The months with the highest humidity are January through March, with an average relative humidity of 88%.
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.
Throughout the year, there are 200.6 rainfall days, and 51.65" (1312mm) of precipitation is accumulated.
Months with snowfall in Index are January through April, November and December.
In Index, during the entire year, snow falls for 15.9 days and aggregates up to 14.41" (366mm) of snow.
January and December, with an average of 3.7h of sunshine, are months with the least sunshine in Index, Washington.
January through April, October through December, with an average maximum UV index of 2, are months with the lowest UV index 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.
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.
May through October are months without snowfall.
With an average of 16h and 0min of daylight, June has the longest days of the year in Index, Washington.
July is the least humid month, with an average relative humidity of 72%.
July is the month with the highest UV index, with an average maximum UV index of 5.
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).
The month with the least rainfall is August, when the rain falls for 7.9 days and typically collects 0.79" (20mm) of precipitation.
August has the most sunshine of the year, with an average of 10.4h of sunshine.
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.
The month with the shortest days in Index is December, with an average of 8h and 30min of daylight.
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 in January:
30.11"Hg - Average pressure in February:
30.07"Hg - Average pressure in March:
30.01"Hg - Average pressure in April:
30.03"Hg - Average pressure in May:
30.01"Hg - Average pressure in June:
30"Hg
- Average pressure in July:
30.02"Hg - Average pressure in August:
29.99"Hg - Average pressure in September:
30"Hg - Average pressure in October:
30.03"Hg - Average pressure in November:
30.04"Hg - Average pressure in December:
30.09"Hg
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 in January:
4.8mph - Average wind speed in February:
4.2mph - Average wind speed in March:
4.3mph - Average wind speed in April:
3.7mph - Average wind speed in May:
3.4mph - Average wind speed in June:
3.3mph
- Average wind speed in July:
3.4mph - Average wind speed in August:
3.2mph - Average wind speed in September:
3.3mph - Average wind speed in October:
3.7mph - Average wind speed in November:
4.4mph - Average wind speed in December:
4.4mph
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
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 in January:
7.8" - Average rainfall in February:
6.06" - Average rainfall in March:
5.75" - Average rainfall in April:
4.25" - Average rainfall in May:
2.76" - Average rainfall in June:
1.97"
- Average rainfall in July:
0.83" - Average rainfall in August:
0.79" - Average rainfall in September:
2.24" - Average rainfall in October:
5.35" - Average rainfall in November:
6.38" - Average rainfall in December:
7.48"
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 in January:
19.5 days - Average rainfall days in February:
17.6 days - Average rainfall days in March:
22.3 days - Average rainfall days in April:
21.2 days - Average rainfall days in May:
17 days - Average rainfall days in June:
15 days
- Average rainfall days in July:
9.6 days - Average rainfall days in August:
7.9 days - Average rainfall days in September:
12.8 days - Average rainfall days in October:
17.3 days - Average rainfall days in November:
20.5 days - Average rainfall days in December:
19.9 days
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
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 in January:
2.4 days - Average snowfall days in February:
5.2 days - Average snowfall days in March:
3.8 days - Average snowfall days in April:
0.8 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:
0.7 days - Average snowfall days in December:
3 days
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 in January:
8h and 54min - Average daylight in February:
10h and 18min - Average daylight in March:
11h and 54min - Average daylight in April:
13h and 42min - Average daylight in May:
15h and 12min - Average daylight in June:
16h and 0min
- Average daylight in July:
15h and 36min - Average daylight in August:
14h and 12min - Average daylight in September:
12h and 30min - Average daylight in October:
10h and 48min - Average daylight in November:
9h and 18min - Average daylight in December:
8h and 30min
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).
- Average sunshine in January:
3h and 42min - Average sunshine in February:
3h and 54min - Average sunshine in March:
5h and 12min - Average sunshine in April:
7h and 0min - Average sunshine in May:
8h and 24min - Average sunshine in June:
8h and 48min
- Average sunshine in July:
10h and 18min - Average sunshine in August:
10h and 24min - Average sunshine in September:
8h and 42min - Average sunshine in October:
5h and 6min - Average sunshine in November:
4h and 0min - Average sunshine in December:
3h and 42min
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 in January:
9.7 days - Average sunshine days in February:
7.9 days - Average sunshine days in March:
7 days - Average sunshine days in April:
7.3 days - Average sunshine days in May:
11.1 days - Average sunshine days in June:
12.7 days
- Average sunshine days in July:
18.3 days - Average sunshine days in August:
19.9 days - Average sunshine days in September:
15 days - Average sunshine days in October:
12.4 days - Average sunshine days in November:
8 days - Average sunshine days in December:
9.4 days
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
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 cloud cover
Index, WA
The months with the most cloud cover are March and December (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 30).
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).
