Keystone
South Dakota, USA
Long-term weather forecast
Long-term weather forecast

Monthly weather forecast and climate
Keystone, SD

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

February, the last month of the winter, in Keystone, is also a subzero cold month, with average temperature ranging between max 31.5°F (-0.3°C) and min 16.2°F (-8.8°C). In February, the average high-temperature is almost the same as in January - a still freezing cold 31.5°F (-0.3°C). Weather in February »

The first month of the spring, March, is a chilly month in Keystone, South Dakota, with 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 freezing cold 31.5°F (-0.3°C) in February, to a chilly 43.9°F (6.6°C). Weather in March »

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

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

June, the first month of the summer, in Keystone, is a warm month, with average temperature varying between 53.2°F (11.8°C) and 74.1°F (23.4°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 »

July, the same as June, is another warm summer month in Keystone, South Dakota, with average temperature ranging between max 81.7°F (27.6°C) and min 60.4°F (15.8°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 appraised at 82.9°F (28.3°C). Weather in July »

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

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

October, the same as September, is a cool autumn month in Keystone, South Dakota, with average temperature ranging between max 54°F (12.2°C) and min 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 »

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

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

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.

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.

What is the driest month in Keystone?

The month with the least rainfall in Keystone is January when the rain falls for 6.2 days and typically collects 0.47" (12mm) of precipitation.

When does it snow in Keystone?

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

How much does it snow in Keystone?

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

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

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?

The month with the least sunshine in Keystone, South Dakota, is February, with an average of 6h of sunshine.

When does it snow the most in Keystone?

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

What is the wettest month in Keystone?

The month with the most rainfall in Keystone 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?

June has the longest days of the year in Keystone, South Dakota, with an average of 15.4h 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?

July is the month with the highest UV index, with an average maximum UV index of 6.

What are the least humid months 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?

With an average of 11.7h of sunshine, August has the most sunshine of the year.

What is the coldest month in Keystone?

The coldest month is December, with an average high-temperature of 29.8°F (-1.2°C) and an average low-temperature of 16.5°F (-8.6°C).

What is the month with the shortest days in Keystone?

December has the shortest days of the year, with an average of 9h of daylight.
Average temperature - Keystone, SD
Average humidity - Keystone, SD
Average rainfall - Keystone, SD

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

Average rainfall days - Keystone, SD

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

Average snowfall - Keystone, SD
Average snowfall days - Keystone, SD

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

Average daylight / Average sunshine - Keystone, SD
Average UV index - Keystone, SD