January weather forecast
Jefferson, SD

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Weather in January

January, the same as December, in Jefferson, South Dakota, is a freezing cold winter month, with an average temperature varying between 27°F (-2.8°C) and 13.1°F (-10.5°C).

Temperature

In Jefferson, the month of January registers the lowest temperatures, averaging 27°F (-2.8°C) at the peak and 13.1°F (-10.5°C) at the lowest.

Humidity

With an average relative humidity of 84%, January is the most humid month.

Rainfall

In Jefferson, South Dakota, in January, it is raining for 3.8 days, with typically 0.75" (19mm) of accumulated precipitation. Throughout the year, there are 122 rainfall days, and 21.61" (549mm) of precipitation is accumulated.

Snowfall

January through May, October through December are months with snowfall in Jefferson. January is the month with the most snowfall in Jefferson. Snow falls for 9.6 days and accumulates 2.95" (75mm) of snow.

Daylight

The average length of the day in January is 9h and 29min.
On the first day of January in Jefferson, sunrise is at 7:56 am and sunset at 5:03 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 5:37 pm CST.

Sunshine

The month with the least sunshine is January, with an average of 4.4h of sunshine.

UV index

January is the month with the lowest UV index, with an average maximum UV index of 1. A UV Index value of 2, and less, symbolizes a minimal health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: The maximum UV index of 1 during January translates into these guidelines:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Alert! The snow's reflection can amplify the UV radiation of the Sun nearly twice.
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Frequently asked questions

What are the coldest months in Jefferson?

In Jefferson, January is the month with the lowest recorded average temperatures, measuring a high of 27°F (-2.8°C) and a low of 13.1°F (-10.5°C).

How cold is it in Jefferson in January?

During January, Jefferson experiences an average high-temperature of 27°F (-2.8°C) and a low-temperature of 13.1°F (-10.5°C).

What is the most humid month in Jefferson?

The most humid month in Jefferson is January, with an average relative humidity of 84%.

What is the average humidity in January in Jefferson?

In January, the average relative humidity is 84%.

How much does it rain in Jefferson in January?

In Jefferson, South Dakota, in January, it is raining for 3.8 days, with typically 0.75" (19mm) of accumulated precipitation.

What is the snowiest month in Jefferson?

January is the month with the most snowfall. Snow falls for 9.6 days and accumulates 2.95" (75mm) of snow.

How much does it snow in Jefferson in January?

In Jefferson, during January, snow falls for 9.6 days and regularly aggregates up to 2.95" (75mm) of snow.

What is the average length of the day in January in Jefferson?

The average day length in January in Jefferson is 9h and 29min.

When are sunrise and sunset in January in Jefferson?

In January, on the first day of the month, sunrise is at 7:56 am and sunset at 5:03 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 5:37 pm CST.

What is the month with the least sunshine in Jefferson?

With an average of 4.4h of sunshine, January has the least sunshine of the year.

How long on average sun shines in January in Jefferson?

In January, the average sunshine duration in Jefferson is 4.4h.

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

January is the month with the lowest UV index in Jefferson, South Dakota, with an average maximum UV index of 1.

What is the UV index intensity in January in Jefferson?

In Jefferson, the average daily maximum UV index in January is 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to UV radiation.
Today
Tomorrow
Long-term
YearJanuaryFMAMJJASOND
Dec
January
Feb
Average high temperature
30.7°F -0.7°C
27°F -2.8°C
30.7°F -0.7°C
Average low temperature
18.7°F -7.4°C
13.1°F -10.5°C
16.7°F -8.5°C
Average pressure
30.13" 765mmHg
30.16" 766mmHg
30.15" 766mmHg
Average wind speed
10.2mph 16.4km/h
10.6mph 17.1km/h
10.5mph 16.9km/h
Average max. wind speed
11mph 17.7km/h
11.4mph 18.3km/h
11.2mph 18km/h
Average wind speed gusts
16.6mph 26.7km/h
17.3mph 27.8km/h
16.5mph 26.6km/h
Average humidity
81%
84%
80%
Average rainfall
1.22" 31mm
0.75" 19mm
0.67" 17mm
Average rainfall days
4.1
3.8
3.3
Average snowfall
2.56" 65mm
2.95" 75mm
2.36" 60mm
Average snowfall days
8.4
9.6
8.3
Average daylight
9h 1min
9h 3min
10h 4min
Average sunshine
4h 5min
4h 2min
5h 2min
Average sunshine days
20.1
19.2
17.3
Average UV index
2
1
2
Average cloud cover
48%
52%
49%
Average visibility
6mi 9.7km
6mi 9.7km
6mi 9.7km

Average temperature in January
Jefferson, SD

Average temperature in January - Jefferson, SD
  • Average high temperature in January: 27°F

The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (27°F).

  • Average low temperature in January: 13.1°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (13.1°F).

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Average pressure in January
Jefferson, SD

Average pressure in January - Jefferson, SD
  • Average pressure in January: 30.16"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).

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Average wind speed in January
Jefferson, SD

Average wind speed in January - Jefferson, SD
  • Average wind speed in January: 10.6mph

The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.6mph).

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Average humidity in January
Jefferson, SD

Average humidity in January - Jefferson, SD
  • Average humidity in January: 84%

The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (65%).

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Average rainfall in January
Jefferson, SD

Average rainfall in January - Jefferson, SD
  • Average rainfall in January: 0.75"

The wettest months (with the highest rainfall) are May and June (3.03").
The driest month (with the least rainfall) is February (0.67").

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Average rainfall days in January
Jefferson, SD

Average rainfall days in January - Jefferson, SD
  • Average rainfall days in January: 3.8 days

The month with the highest number of rainy days is June (17.8 days).
The month with the least rainy days is February (3.3 days).

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Average snowfall in January
Jefferson, SD

Average snowfall in January - Jefferson, SD
  • Average snowfall in January: 2.95"

The month with the highest snowfall is January (2.95").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in January
Jefferson, SD

Average snowfall days in January - Jefferson, SD
  • Average snowfall days in January: 9.6 days

The month with the highest number of snowfall days is January (9.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in January /
Average sunshine in January
Jefferson, SD

Average daylight in January / Average sunshine in January - Jefferson, SD
  • Average daylight in January: 9h and 3min

The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in January: 4h and 2min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

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Average sunshine days in January
Jefferson, SD

Average sunshine days in January - Jefferson, SD
  • Average sunshine days in January: 19.2 days

The month with the most sunshine days is November (20.9 days).
The month with the least sunshine days is June (9.7 days).

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Average UV index in January
Jefferson, SD

Average UV index in January - Jefferson, SD
  • Average UV index in January: 1

The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).

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Average cloud cover in January
Jefferson, SD

Average cloud cover in January - Jefferson, SD
  • Average cloud cover in January: 52

The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is July (Cloud cover 26).

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Average visibility in January
Jefferson, SD

Average visibility in January - Jefferson, SD
  • Average visibility in January: 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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Jefferson, South Dakota, USA

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