October weather forecast
Keystone, SD

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Weather in October

October is a transitional period for Keystone city weather with decreasing temperatures and a remarkable increase in rainfall rates. A significant drop in average temperature is noted with highs of around 54°F (12.2°C), indicating the gradual onset of winter. Instances of rain are common in the city during this month, leading to damp conditions. While the daylight hours decrease, the colorful spectacle of fall foliage remains a highlight for October's weather. As October gives way to November, the cooling trend continues and prepares the city for the forthcoming winter.

Temperature

A clear decrease in the average high-temperature is observed in Keystone during October, decreasing from an agreeable 71.4°F (21.9°C) in September to a fresh 54°F (12.2°C). Throughout October, Keystone experiences a low-temperature average of 36.7°F (2.6°C).

Humidity

The average relative humidity in October is 61%.

Rainfall

In Keystone, in October, it is raining for 9 days, with typically 1.14" (29mm) of accumulated precipitation. In Keystone, during the entire year, the rain falls for 135.4 days and collects up to 20.39" (518mm) of precipitation.

Snowfall

January through May, September through December are months with snowfall. In Keystone, during October, snow falls for 5.3 days and regularly aggregates up to 3.66" (93mm) of snow. Throughout the year, in Keystone, there are 75.1 snowfall days, and 40.24" (1022mm) of snow is accumulated.

Daylight

In October, the average length of the day in Keystone is 10h and 59min.
On the first day of October, sunrise is at 6:52 am and sunset at 6:33 pm. On the last day of the month, sunrise is at 7:29 am and sunset at 5:44 pm MDT.

Sunshine

In October, the average sunshine is 7.1h.

UV index

The months with the lowest UV index in Keystone, South Dakota, are January through March, October through December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for the average person.
Note: A maximum daily UV index of 2 during October morphs into the following directions:
Though the majority can handle prolonged sun exposure, it is crucial to always shield babies, children, and those with fair skin. The solar radiation around mid-day is intense; avoid the Sun and stay safe. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
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Frequently asked questions

What is the usual temperature for Keystone in October?

The high-temperature during October is 54°F (12.2°C) and the low-temperature is 36.7°F (2.6°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), which takes the relative humidity and factors it into the air temperature reading, in July is evaluated at 82.4°F (28°C).

What is the average humidity in October in Keystone?

In October, the average relative humidity in Keystone, South Dakota, is 61%.

How much does it rain in Keystone in October?

In Keystone, South Dakota, during October, the rain falls for 9 days and regularly aggregates up to 1.14" (29mm) of precipitation.

How many days does it snow in October in Keystone?

In Keystone, in October, during 5.3 snowfall days, 3.66" (93mm) of snow is typically accumulated.

How many hours of daylight does Keystone have in October?

The average day length in October in Keystone, South Dakota, is 10h and 59min.

What time are sunrise and sunset in October in Keystone?

On the first day of October in Keystone, South Dakota, sunrise is at 6:52 am and sunset at 6:33 pm. On the last day of the month, sunrise is at 7:29 am and sunset at 5:44 pm MDT.

How many hours of sunshine does Keystone have in October?

The average sunshine duration in October in Keystone is 7.1h.

What are the months 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.

How high is the UV index in October in Keystone?

The average daily maximum UV index in October in Keystone is 2. A UV Index reading of 2, and below, represents a low health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in October
Keystone, SD

Average temperature in October - Keystone, SD
  • Average high temperature in October: 54°F

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).

  • Average low temperature in October: 36.7°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 in October
Keystone, SD

Average pressure in October - Keystone, SD
  • Average pressure in October: 29.98"Hg

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 in October
Keystone, SD

Average wind speed in October - Keystone, SD
  • Average wind speed in October: 9.1mph

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 in October
Keystone, SD

Average humidity in October - Keystone, SD
  • Average humidity in October: 61%

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 in October
Keystone, SD

Average rainfall in October - Keystone, SD
  • Average rainfall in October: 1.14"

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 in October
Keystone, SD

Average rainfall days in October - Keystone, SD
  • Average rainfall days in October: 9 days

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 in October
Keystone, SD

Average snowfall in October - Keystone, SD
  • Average snowfall in October: 3.66"

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 in October
Keystone, SD

Average snowfall days in October - Keystone, SD
  • Average snowfall days in October: 5.3 days

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 in October /
Average sunshine in October
Keystone, SD

Average daylight in October / Average sunshine in October - Keystone, SD
  • Average daylight in October: 11h and 0min

The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).

  • Average sunshine in October: 7h and 1min

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 in October
Keystone, SD

Average sunshine days in October - Keystone, SD
  • Average sunshine days in October: 17.4 days

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 in October
Keystone, SD

Average UV index in October - Keystone, SD
  • Average UV index in October: 2

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 cloud cover in October
Keystone, SD

Average cloud cover in October - Keystone, SD
  • Average cloud cover in October: 27

The month with the most cloud cover is April (Cloud cover 38).
The month with the least cloud cover is August (Cloud cover 17).

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Average visibility in October
Keystone, SD

Average visibility in October - Keystone, SD
  • Average visibility in October: 6mi

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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Keystone, South Dakota, USA

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