January weather forecast
Sully, IA

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Weather in January

January, like December, is another subzero cold winter month in Sully, Iowa, with an average temperature ranging between max 27.1°F (-2.7°C) and min 14.4°F (-9.8°C).

Temperature

Temperature records mark January as the coldest month, with highs averaging 27.1°F (-2.7°C) and lows at 14.4°F (-9.8°C).

Humidity

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

Rainfall

The months with the least rainfall in Sully are January, February and December Rain falls for 3.8 days and accumulates 0.39" (10mm) of rain.

Snowfall

January through May, October through December are months with snowfall in Sully. The month with the most snowfall is January, when snow falls for 8.4 days and typically aggregates up to 1.73" (44mm) of snow.

Daylight

The average length of the day in January in Sully is 9h and 35min.
On the first day of the month, sunrise is at 7:37 am and sunset at 4:51 pm. On the last day of January, in Sully, sunrise is at 7:24 am and sunset at 5:25 pm CST.

Sunshine

With an average of 4.2h of sunshine, January has the least sunshine of the year in Sully.

UV index

January and December, with an average maximum UV index of 1, are months with the lowest UV index in Sully, Iowa. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for average individuals.
Note: A daily maximum UV index of 1 in January translates into the following instructions:
While many people can endure lengthy sun exposure, it remains imperative to safeguard babies, children, and fair-skinned individuals. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Heed this! Snow reflection can almost augment the UV radiation of the sun by double.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest month in Sully?

January is the coldest month of the year, registering average temperatures as high as 27.1°F (-2.7°C) and as low as 14.4°F (-9.8°C).

How cold is it in Sully in January?

In Sully, in January, the average high-temperature is 27.1°F (-2.7°C), and the average low-temperature is 14.4°F (-9.8°C).

What is the most humid month in Sully?

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

What is the average humidity in January in Sully?

In January, the average relative humidity in Sully is 84%.

What is the driest month in Sully?

The months with the least rainfall in Sully are January, February and December Rain falls for 3.8 days and accumulates 0.39" (10mm) of rain.

How many days does it rain in January in Sully?

In January, the rain falls for 3.8 days. Throughout January, 0.39" (10mm) of precipitation is accumulated.

What is the snowiest month in Sully?

January is the month with the most snowfall in Sully, Iowa. Snow falls for 8.4 days and accumulates 1.73" (44mm) of snow.

How much does it snow in Sully in January?

In Sully, in January, during 8.4 snowfall days, 1.73" (44mm) of snow is typically accumulated.

How many hours of daylight does Sully have in January?

The average day length in January in Sully, Iowa, is 9h and 35min.

When are sunrise and sunset in January in Sully?

On the first day of January in Sully, sunrise is at 7:37 am and sunset at 4:51 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 5:25 pm CST.

What is the month with the least sunshine in Sully?

January has the least sunshine of the year in Sully, Iowa, with an average of 4.2h of sunshine.

How many hours of sunshine does Sully have in January?

In Sully, Iowa, the average sunshine duration in January is 4.2h.

What are the months with the lowest UV index in Sully?

January and December, with an average maximum UV index of 1, are months with the lowest UV index in Sully, Iowa.

What is the UV index intensity in January in Sully?

In January, the average daily maximum UV index is 1. A UV Index estimate of 2, and below, represents a low health risk from 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 January
Sully, IA

Average temperature in January - Sully, IA
  • Average high temperature in January: 27.1°F

The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (27.1°F).

  • Average low temperature in January: 14.4°F

The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (14.4°F).

Average pressure in January
Sully, IA

Average pressure in January - Sully, IA
  • Average pressure in January: 30.15"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

Average wind speed in January
Sully, IA

Average wind speed in January - Sully, IA
  • Average wind speed in January: 10.5mph

The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).

Average humidity in January
Sully, IA

Average humidity in January - Sully, IA
  • Average humidity in January: 84%

The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (71%).

Average rainfall in January
Sully, IA

Average rainfall in January - Sully, IA
  • Average rainfall in January: 0.39"

The wettest month (with the highest rainfall) is May (2.13").
The driest months (with the least rainfall) are January, February and December (0.39").

Average rainfall days in January
Sully, IA

Average rainfall days in January - Sully, IA
  • Average rainfall days in January: 3.8 days

The month with the highest number of rainy days is May (14.7 days).
The month with the least rainy days is February (3.4 days).

Average snowfall in January
Sully, IA

Average snowfall in January - Sully, IA
  • Average snowfall in January: 1.73"

The month with the highest snowfall is January (1.73").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in January
Sully, IA

Average snowfall days in January - Sully, IA
  • Average snowfall days in January: 8.4 days

The month with the highest number of snowfall days is January (8.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in January /
Average sunshine in January
Sully, IA

Average daylight in January / Average sunshine in January - Sully, IA
  • Average daylight in January: 9h and 4min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in January: 4h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).

Average sunshine days in January
Sully, IA

Average sunshine days in January - Sully, IA
  • Average sunshine days in January: 21.8 days

The month with the most sunshine days is December (22.9 days).
The month with the least sunshine days is June (12.2 days).

Average UV index in January
Sully, IA

Average UV index in January - Sully, IA
  • Average UV index in January: 1

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

Average cloud cover in January
Sully, IA

Average cloud cover in January - Sully, IA
  • Average cloud cover in January: 55

The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and September (Cloud cover 30).

Average visibility in January
Sully, IA

Average visibility in January - Sully, IA
  • Average visibility in January: 6mi

The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).

Sully, Iowa, USA

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