Climate and monthly weather forecast
Keystone, SD

Weather in January

January, the same as December, in Keystone, South Dakota, is another subzero cold winter month, with an average temperature varying between 17.1°F (-8.3°C) and 31.1°F (-0.5°C). In Keystone, the average high-temperature in January is essentially the same as in December - a still freezing cold 31.1°F (-0.5°C). Weather in January »

Weather in February

The last month of the winter, February, is also a subzero cold month in Keystone, South Dakota, with an average temperature fluctuating between 16.2°F (-8.8°C) and 31.5°F (-0.3°C). In Keystone, the average high-temperature in February is practically the same as in January - a still subzero cold 31.5°F (-0.3°C). Weather in February »

Weather in March

March, the first month of the spring in Keystone, is a frosty month, with an average temperature ranging between max 43.9°F (6.6°C) and min 26.4°F (-3.1°C). In March, the average high-temperature rises from a subzero cold 31.5°F (-0.3°C) in February to a chilly 43.9°F (6.6°C). Weather in March »

Weather in April

April in Keystone, South Dakota, is a fresh spring month, with an average temperature varying between 50.9°F (10.5°C) and 32.5°F (0.3°C). In Keystone, the average high-temperature in April slightly increases from a frosty 43.9°F (6.6°C) in March to a fresh 50.9°F (10.5°C). Weather in April »

Weather in May

May, the last month of the spring in Keystone, is a comfortable month, with temperature in the range of an average low of 42.4°F (5.8°C) and an average high of 61°F (16.1°C). In Keystone, the average high-temperature in May increases from a fresh 50.9°F (10.5°C) in April to a comfortable 61°F (16.1°C). Weather in May »

Weather in June

June, the first month of the summer in Keystone, is a moderately hot month, with an average temperature fluctuating between 74.1°F (23.4°C) and 53.2°F (11.8°C). In Keystone, South Dakota, the average high-temperature in June increases from a comfortable 61°F (16.1°C) in May to a moderately hot 74.1°F (23.4°C). Weather in June »

Weather in July

July, like June, in Keystone, South Dakota, is a moderately hot summer month, with an average temperature varying between 60.4°F (15.8°C) and 81.7°F (27.6°C). July is the warmest month, with an average high-temperature of 81.7°F (27.6°C) and an average low-temperature of 60.4°F (15.8°C). The average heat index in July is calculated to be 82.4°F (28°C). Weather in July »

Weather in August

August, the last month of the summer in Keystone, is also a moderately hot month, with an average temperature fluctuating between 58.3°F (14.6°C) and 80.1°F (26.7°C). In August, the average high-temperature is practically the same as in July - a still moderately hot 80.1°F (26.7°C). Weather in August »

Weather in September

September, the first month of the autumn in Keystone, is also an agreeable month, with an average temperature ranging between min 51.1°F (10.6°C) and max 71.4°F (21.9°C). In Keystone, the average high-temperature in September slightly decreases from a warm 80.1°F (26.7°C) in August to a pleasant 71.4°F (21.9°C). Weather in September »

Weather in October

October, like September, in Keystone, South Dakota, is a cool autumn month, with an average temperature varying between 54°F (12.2°C) and 36.7°F (2.6°C). In Keystone, the average high-temperature in October declines considerably from a pleasant 71.4°F (21.9°C) in September to a fresh 54°F (12.2°C). Weather in October »

Weather in November

November, the last month of the autumn in Keystone, is also a wintry month, with an average temperature varying between 25.9°F (-3.4°C) and 42.3°F (5.7°C). In November, the average high-temperature drops from a cool 54°F (12.2°C) in October to a cold 42.3°F (5.7°C). Weather in November »

Weather in December

The first month of the winter, December, is still a freezing cold month in Keystone, South Dakota, with temperature in the range of an average low of 16.5°F (-8.6°C) and an average high of 29.8°F (-1.2°C). With an average high-temperature of 29.8°F (-1.2°C) and an average low-temperature of 16.5°F (-8.6°C), December is the coldest month. Weather in December »
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FAQ

What are the most humid months in Keystone?

January and February, with an average relative humidity of 77%, are most humid months in Keystone, South Dakota.

What is the driest month in Keystone?

January is the month with the least rainfall. Rain falls for 6.2 days and accumulates 0.47" (12mm) of precipitation.

How much does it rain in Keystone?

In Keystone, South Dakota, during the entire year, the rain falls for 135.4 days and collects up to 20.39" (518mm) of precipitation.

When does it snow in Keystone?

Months with snowfall in Keystone are January through May, September through December.

How much does it snow in Keystone?

In Keystone, South Dakota, during the entire year, snow falls for 75.1 days and aggregates up to 40.24" (1022mm) of snow.

When is the lowest UV index in Keystone?

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

What is the month with the least sunshine in Keystone?

With an average of 6h of sunshine, February has the least sunshine of the year in Keystone.

When is Daylight Saving Time (DST) in Keystone?

On Sunday, March 13. 2022, at 2:00 am, Daylight Saving Time starts, and the time zone changes from MST to MDT. Daylight Saving Time ends Sunday, November 6. 2022, at 2:00 am, and the time zone reverts from MDT to MST.

When does it snow the most in Keystone?

April is the month with the most snowfall in Keystone, South Dakota. Snow falls for 8.8 days and accumulates 7.24" (184mm) of snow.

What is the wettest month in Keystone?

The month with the most rainfall in Keystone, South Dakota, is June, when the rain falls for 18 days and typically aggregates up to 3.19" (81mm) of precipitation.

When it does not snow in Keystone?

In Keystone, South Dakota, snow does not fall in June through August.

When are the longest days in Keystone?

With an average of 15h and 25min of daylight, June has the longest days of the year in Keystone.

What is the warmest month in Keystone?

July is the warmest month in Keystone, with an average high-temperature of 81.7°F (27.6°C) and an average low-temperature of 60.4°F (15.8°C).

When is the highest UV index in Keystone?

The month with the highest UV index in Keystone, South Dakota, is July, with an average maximum UV index of 6.

What is the least humid month in Keystone?

August and September, with an average relative humidity of 52%, are the least humid months in Keystone.

What month has the most sunshine in Keystone?

The month with the most sunshine in Keystone is August, with an average of 11.7h of sunshine.

What is the coldest month in Keystone?

With an average high-temperature of 29.8°F (-1.2°C) and an average low-temperature of 16.5°F (-8.6°C), December is the coldest month in Keystone.

What is the month with the shortest days in Keystone?

December has the shortest days of the year in Keystone, with an average of 8h and 58min of daylight.

Average temperature
Keystone, SD

Average temperature - Keystone, SD

The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is December (29.8°F).

The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is February (16.2°F).

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Average pressure
Keystone, SD

Average pressure - Keystone, SD

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).

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Average wind speed
Keystone, SD

Average wind speed - Keystone, SD

The windiest month (with the highest average wind speed) is April (9.5mph).
The calmest month (with the lowest average wind speed) is August (7mph).

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Average humidity
Keystone, SD

Average humidity - Keystone, SD

The months with the highest relative humidity are January and February (77%).
The months with the lowest relative humidity are August and September (52%).

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Average rainfall
Keystone, SD

Average rainfall - Keystone, SD

The wettest month (with the highest rainfall) is June (3.19").
The driest month (with the least rainfall) is January (0.47").

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Average rainfall days
Keystone, SD

Average rainfall days - Keystone, SD

The month with the highest number of rainy days is May (18.6 days).
The month with the least rainy days is November (4.5 days).

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Average snowfall
Keystone, SD

Average snowfall - Keystone, SD

The month with the highest snowfall is April (7.24").
The months with the least snowfall are June, July and August (0").

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Average snowfall days
Keystone, SD

Average snowfall days - Keystone, SD

The month with the highest number of snowfall days is February (12.9 days).
The months with the least snowfall days are June, July and August (0 days).

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Average daylight / Average sunshine
Keystone, SD

Average daylight / Average sunshine - Keystone, SD

The month with the longest days is June (Average daylight: 15h and 25min).
The month with the shortest days is December (Average daylight: 8h and 58min).

The month with the most sunshine is August (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 6h and 0min).

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Average sunshine days
Keystone, SD

Average sunshine days - Keystone, SD

The month with the most sunshine days is November (19.2 days).
The month with the least sunshine days is May (7.8 days).

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Average UV index
Keystone, SD

Average UV index - Keystone, SD

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

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Average visibility
Keystone, SD

Average visibility - Keystone, SD

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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