Climate and monthly weather forecast
Keystone, SD

Weather in January

January, like December, is another subzero cold winter month in Keystone, South Dakota, with an average temperature varying between 17.1°F (-8.3°C) and 31.1°F (-0.5°C). In January, the average high-temperature is relatively 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 another freezing cold month in Keystone, South Dakota, with an average temperature ranging between min 16.2°F (-8.8°C) and max 31.5°F (-0.3°C). In Keystone, the average high-temperature in February is almost the same as in January - a still freezing cold 31.5°F (-0.3°C). Weather in February »

Weather in March

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

Weather in April

April in Keystone, South Dakota, is a cool 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 marginally rises from a frosty 43.9°F (6.6°C) in March to a cool 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 an average temperature ranging between max 61°F (16.1°C) and min 42.4°F (5.8°C). In Keystone, South Dakota, the average high-temperature in May increases from a fresh 50.9°F (10.5°C) in April to an enjoyable 61°F (16.1°C). Weather in May »

Weather in June

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

Weather in July

July, the same as June, is another warm summer month in Keystone, South Dakota, with temperature in the range of an average low of 60.4°F (15.8°C) and an average high of 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). In July, the average heat index is computed to be 82.9°F (28.3°C). Weather in July »

Weather in August

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

Weather in September

The first month of the autumn, September, is also an agreeable month in Keystone, South Dakota, with an average temperature varying between 71.4°F (21.9°C) and 51.1°F (10.6°C). In September, the average high-temperature marginally drops from a moderately hot 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 temperature in the range of an average high of 54°F (12.2°C) and an average low of 36.7°F (2.6°C). In October, the average high-temperature plummets from an agreeable 71.4°F (21.9°C) in September to a fresh 54°F (12.2°C). Weather in October »

Weather in November

The last month of the autumn, November, is another cold month in Keystone, South Dakota, with temperature in the range of an average low of 25.9°F (-3.4°C) and an average high of 42.3°F (5.7°C). In Keystone, South Dakota, the average high-temperature in November decreases from a fresh 54°F (12.2°C) in October to a wintry 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 an average temperature ranging between max 29.8°F (-1.2°C) and min 16.5°F (-8.6°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.

What is the driest month in Keystone?

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

How much does it rain in Keystone?

Throughout the year, in Keystone, there are 135.4 rainfall days, and 20.39" (518mm) of precipitation is accumulated.

When does it snow in Keystone?

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

How many days does it snow in Keystone?

Throughout the year, there are 75.1 snowfall days, and 40.24" (1022mm) of snow is accumulated.

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

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

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.

When is Daylight Saving Time (DST) in Keystone?

On Sunday, March 13. 2022, at 2:00 am, Daylight Saving Time starts in Keystone, 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.

What is the snowiest month in Keystone?

The month with the most snowfall in Keystone, South Dakota, is April, when snow falls for 8.8 days and typically aggregates up to 7.24" (184mm) of snow.

What is the rainiest month in Keystone?

June is the month with the most rainfall. Rain falls for 18 days and accumulates 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?

The month with the longest days is June, with an average of 15h and 25min of daylight.

What is the warmest month in Keystone?

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).

When is the highest UV index in Keystone?

The month with the highest UV index 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.

What is the month with the shortest days in Keystone?

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

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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