January weather forecast
Mattawa, WA

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Weather in January

January, like December, in Mattawa, Washington, is a wintry winter month, with an average temperature ranging between min 25.9°F (-3.4°C) and max 35.4°F (1.9°C).

Temperature

At the start of January, Mattawa's average high-temperature reaches a still cold 35.4°F (1.9°C), subtly different from the preceding month. Nighttime temperature in Mattawa dips to a mean of 25.9°F (-3.4°C) during January.

Humidity

With an average relative humidity of 83%, January is the most humid month in Mattawa.

Rainfall

The months with the most rainfall are January and December, with an average 0.87" (22mm) of precipitation.

Snowfall

Months with snowfall in Mattawa are January through April, September, November and December. In Mattawa, in January, during 6.3 snowfall days, 2.99" (76mm) of snow is typically accumulated. Throughout the year, there are 22.3 snowfall days, and 10" (254mm) of snow is accumulated.

Daylight

The average length of the day in January in Mattawa, Washington, is 9h and 4min.
On the first day of January, sunrise is at 7:44 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 5:00 pm PST.

Sunshine

The month with the least sunshine is January, with an average of 4.9h of sunshine.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Mattawa. A UV Index value of 2, and less, symbolizes a minimal health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: A daily high UV index of 2 in January leads to these guidelines:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses. Stay alert! Snow's reflective properties can almost double the UV radiation from the Sun.
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Frequently asked questions

How cold is it in Mattawa in January?

The high-temperature, in January, in Mattawa, records 35.4°F (1.9°C), while the low-temperature is 25.9°F (-3.4°C).

What is the most humid month in Mattawa?

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

What is the average humidity in January in Mattawa?

The average relative humidity in January in Mattawa, Washington, is 83%.

What is the rainiest month in Mattawa?

The months with the most rainfall in Mattawa are January and December, with an average 0.87" (22mm) of precipitation.

How much does it rain in Mattawa in January?

In Mattawa, Washington, in January, during 8.5 rainfall days, 0.87" (22mm) of precipitation is typically accumulated.

How many days does it snow in January in Mattawa?

In Mattawa, Washington, during January, snow falls for 6.3 days and regularly aggregates up to 2.99" (76mm) of snow.

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

In Mattawa, Washington, the average day length in January is 9h and 4min.

When is the sunrise / sunset in January in Mattawa?

In January, on the first day of the month, sunrise is at 7:44 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 5:00 pm PST.

What is the month with the least sunshine in Mattawa?

January has the least sunshine of the year in Mattawa, with an average of 4.9h of sunshine.

How many hours of sunshine does Mattawa have in January?

In January, the average sunshine duration is 4.9h.

When is the lowest UV index in Mattawa?

The months with the lowest UV index in Mattawa, Washington, are January, February, November and December, with an average maximum UV index of 2.

What is the UV index intensity in January in Mattawa?

In Mattawa, Washington, the average daily maximum UV index in January is 2. A UV Index reading of 2, and below, represents a low health threat 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
Mattawa, WA

Average temperature in January - Mattawa, WA
  • Average high temperature in January: 35.4°F

The warmest months (with the highest average high temperature) are July and August (88.3°F).
The month with the lowest average high temperature is December (34.5°F).

  • Average low temperature in January: 25.9°F

The month with the highest average low temperature is August (61.5°F).
The coldest month (with the lowest average low temperature) is December (24.3°F).

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Average pressure in January
Mattawa, WA

Average pressure in January - Mattawa, WA
  • Average pressure in January: 30.17"Hg

The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).

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Average wind speed in January
Mattawa, WA

Average wind speed in January - Mattawa, WA
  • Average wind speed in January: 4.9mph

The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest month (with the lowest average wind speed) is December (4.7mph).

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Average humidity in January
Mattawa, WA

Average humidity in January - Mattawa, WA
  • Average humidity in January: 83%

The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is July (37%).

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Average rainfall in January
Mattawa, WA

Average rainfall in January - Mattawa, WA
  • Average rainfall in January: 0.87"

The wettest months (with the highest rainfall) are January and December (0.87").
The driest month (with the least rainfall) is August (0.2").

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Average rainfall days in January
Mattawa, WA

Average rainfall days in January - Mattawa, WA
  • Average rainfall days in January: 8.5 days

The month with the highest number of rainy days is March (10.6 days).
The month with the least rainy days is August (3.5 days).

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Average snowfall in January
Mattawa, WA

Average snowfall in January - Mattawa, WA
  • Average snowfall in January: 2.99"

The month with the highest snowfall is December (3.43").
The months with the least snowfall are May, June, July, August and October (0").

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Average snowfall days in January
Mattawa, WA

Average snowfall days in January - Mattawa, WA
  • Average snowfall days in January: 6.3 days

The month with the highest number of snowfall days is December (6.5 days).
The months with the least snowfall days are May, June, July and August (0 days).

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Average daylight in January /
Average sunshine in January
Mattawa, WA

Average daylight in January / Average sunshine in January - Mattawa, WA
  • Average daylight in January: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).

  • Average sunshine in January: 4h and 5min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 54min).

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Average sunshine days in January
Mattawa, WA

Average sunshine days in January - Mattawa, WA
  • Average sunshine days in January: 18 days

The months with the most sunshine days are July and August (25.8 days).
The month with the least sunshine days is February (16 days).

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Average UV index in January
Mattawa, WA

Average UV index in January - Mattawa, WA
  • Average UV index in January: 2

The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in January
Mattawa, WA

Average cloud cover in January - Mattawa, WA
  • Average cloud cover in January: 47

The month with the most cloud cover is January (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 10).

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Average visibility in January
Mattawa, WA

Average visibility in January - Mattawa, WA
  • Average visibility in January: 5mi

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

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Mattawa, Washington, USA

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