January weather forecast
Portsmouth, IA

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Weather in January

January, like December, is a freezing cold winter month in Portsmouth, Iowa, with an average temperature ranging between min 14.5°F (-9.7°C) and max 27.3°F (-2.6°C).

Temperature

The month of January, characterized by an average high of 27.3°F (-2.6°C) and a low of 14.5°F (-9.7°C), is recognized as the coldest.

Humidity

The most humid month in Portsmouth is January, with an average relative humidity of 83%.

Rainfall

The month with the least rainfall is January, when the rain falls for 3.2 days and typically collects 0.43" (11mm) of precipitation.

Snowfall

Months with snowfall in Portsmouth are January through May, October through December. In January, in Portsmouth, it is snowing for 8.3 days. Throughout January, 1.57" (40mm) of snow is accumulated. In Portsmouth, during the entire year, snow falls for 31.5 days and aggregates up to 7.13" (181mm) of snow.

Daylight

In Portsmouth, the average length of the day in January is 9h and 34min.
On the first day of the month, sunrise is at 7:48 am and sunset at 5:02 pm. On the last day of January, sunrise is at 7:35 am and sunset at 5:35 pm CST.

Sunshine

With an average of 4.5h of sunshine, January has the least sunshine of the year in Portsmouth.

UV index

January, February, October through December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV rays for the average person.
Note: The daily high UV index of 2 in January translates into this advice:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Take precaution! The reflection from snow can almost double the UV radiation of the Sun.
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Frequently asked questions

What is the coldest month in Portsmouth?

Portsmouth experiences its average lowest temperatures in January, reaching a peak of 27.3°F (-2.6°C) and a minimum of 14.5°F (-9.7°C).

How cold is it in Portsmouth in January?

In January, the average high-temperature and low-temperature in Portsmouth, Iowa, are 27.3°F (-2.6°C) and 14.5°F (-9.7°C) respectively.

What is the most humid month in Portsmouth?

The most humid month in Portsmouth, Iowa, is January, with an average relative humidity of 83%.

What is the average humidity in January in Portsmouth?

The average relative humidity in January in Portsmouth is 83%.

What is the driest month in Portsmouth?

January is the month with the least rainfall in Portsmouth. Rain falls for 3.2 days and accumulates 0.43" (11mm) of precipitation.

How many days does it rain in January in Portsmouth?

In Portsmouth, Iowa, in January, during 3.2 rainfall days, 0.43" (11mm) of precipitation is typically accumulated.

How many days does it snow in January in Portsmouth?

In Portsmouth, in January, during 8.3 snowfall days, 1.57" (40mm) of snow is typically accumulated.

How many hours of daylight does Portsmouth have in January?

In Portsmouth, the average day length in January is 9h and 34min.

When are sunrise and sunset in January in Portsmouth?

On the first day of January in Portsmouth, sunrise is at 7:48 am and sunset at 5:02 pm. On the last day of the month, sunrise is at 7:35 am and sunset at 5:35 pm CST.

What is the month with the least sunshine in Portsmouth?

The month with the least sunshine in Portsmouth is January, with an average of 4.5h of sunshine.

How many hours of sunshine does Portsmouth have in January?

The average sunshine duration in January in Portsmouth, Iowa, is 4.5h.

When is the lowest UV index in Portsmouth?

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

What is the UV index intensity in January in Portsmouth?

In January, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a minimal hazard to health from exposure to the Sun's UV radiation.
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
Portsmouth, IA

Average temperature in January - Portsmouth, IA
  • Average high temperature in January: 27.3°F

The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is January (27.3°F).

  • Average low temperature in January: 14.5°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 (14.5°F).

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Average pressure in January
Portsmouth, IA

Average pressure in January - Portsmouth, IA
  • 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 (29.87"Hg).

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Average wind speed in January
Portsmouth, IA

Average wind speed in January - Portsmouth, IA
  • Average wind speed in January: 10.6mph

The windiest month (with the highest average wind speed) is April (10.9mph).
The calmest month (with the lowest average wind speed) is July (7.2mph).

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Average humidity in January
Portsmouth, IA

Average humidity in January - Portsmouth, IA
  • Average humidity in January: 83%

The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is October (68%).

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Average rainfall in January
Portsmouth, IA

Average rainfall in January - Portsmouth, IA
  • Average rainfall in January: 0.43"

The wettest month (with the highest rainfall) is June (2.64").
The driest month (with the least rainfall) is January (0.43").

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Average rainfall days in January
Portsmouth, IA

Average rainfall days in January - Portsmouth, IA
  • Average rainfall days in January: 3.2 days

The month with the highest number of rainy days is June (16.1 days).
The month with the least rainy days is February (2.8 days).

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Average snowfall in January
Portsmouth, IA

Average snowfall in January - Portsmouth, IA
  • Average snowfall in January: 1.57"

The month with the highest snowfall is February (2.09").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in January
Portsmouth, IA

Average snowfall days in January - Portsmouth, IA
  • Average snowfall days in January: 8.3 days

The month with the highest number of snowfall days is January (8.3 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
Portsmouth, IA

Average daylight in January / Average sunshine in January - Portsmouth, 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 3min

The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).

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Average sunshine days in January
Portsmouth, IA

Average sunshine days in January - Portsmouth, IA
  • Average sunshine days in January: 20.1 days

The month with the most sunshine days is December (21.6 days).
The month with the least sunshine days is June (11.4 days).

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Average UV index in January
Portsmouth, IA

Average UV index in January - Portsmouth, IA
  • Average UV index in January: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).

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Average cloud cover in January
Portsmouth, IA

Average cloud cover in January - Portsmouth, IA
  • 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 27).

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Average visibility in January
Portsmouth, IA

Average visibility in January - Portsmouth, IA
  • 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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Portsmouth, Iowa, USA

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