December weather forecast
Rochester, WA

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Weather in December

December, the first month of the winter in Rochester, is also an icy month, with an average temperature varying between 33.1°F (0.6°C) and 42.6°F (5.9°C).

Temperature

Rochester notes the coldest temperatures in December, with a high average of 42.6°F (5.9°C) and a low of 33.1°F (0.6°C).

Humidity

In December, the average relative humidity is 89%.

Rainfall

In Rochester, during December, the rain falls for 17.9 days and regularly aggregates up to 3.74" (95mm) of precipitation. In Rochester, Washington, during the entire year, the rain falls for 168 days and collects up to 23.94" (608mm) of precipitation.

Snowfall

Months with snowfall are January through March, November and December. In December, in Rochester, it is snowing for 1.2 days. Throughout December, 0.31" (8mm) of snow is accumulated. In Rochester, during the entire year, snow falls for 7.9 days and aggregates up to 4.02" (102mm) of snow.

Daylight

The month with the shortest days in Rochester is December, with an average of 8h and 36min of daylight.
On the first day of December in Rochester, sunrise is at 7:37 am and sunset at 4:25 pm. On the last day of the month, sunrise is at 7:57 am and sunset at 4:34 pm PST.

Sunshine

December has the least sunshine of the year, with an average of 3.5h of sunshine.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: In December, the maximum UV index of 2 suggests these recommendations:
Most individuals can handle sun exposure for up to an hour without burning, but children must always be shielded from sun exposure. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Take heed! The reflection of snow can intensify the Sun's UV radiation nearly double.
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Frequently asked questions

What month is the coldest in Rochester?

The coldest temperatures occur during December, when averages reach a peak of 42.6°F (5.9°C) and a low of 33.1°F (0.6°C).

How cold does it get in Rochester in December?

December temperatures in Rochester vary between a high-temperature of 42.6°F (5.9°C) and a low-temperature of 33.1°F (0.6°C).

What is the average humidity in December in Rochester?

The average relative humidity in December in Rochester is 89%.

How many days does it rain in December in Rochester?

In Rochester, Washington, in December, it is raining for 17.9 days, with typically 3.74" (95mm) of accumulated precipitation.

How many days does it snow in December in Rochester?

In Rochester, Washington, during December, snow falls for 1.2 days and regularly aggregates up to 0.31" (8mm) of snow.

What is the month with the shortest days in Rochester?

The month with the shortest days is December, with an average of 8h and 36min of daylight.

What is the average length of the day in December in Rochester?

In Rochester, Washington, the average day length in December is 8h and 37min.

What time are sunrise and sunset in December in Rochester?

In December, on the first day of the month, sunrise is at 7:37 am and sunset at 4:25 pm. On the last day of the month, in Rochester, sunrise is at 7:57 am and sunset at 4:34 pm PST.

What is the month with the least sunshine in Rochester?

With an average of 3.5h of sunshine, December has the least sunshine of the year.

How many hours of sunshine does Rochester have in December?

In December, the average sunshine duration in Rochester is 3.5h.

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

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

What is the UV index intensity in December in Rochester?

The average daily maximum UV index in December in Rochester is 2. A UV Index value of 2, and less, symbolizes a minimal hazard to health from unprotected exposure to 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 December
Rochester, WA

Average temperature in December - Rochester, WA
  • Average high temperature in December: 42.6°F

The warmest month (with the highest average high temperature) is August (77.4°F).
The month with the lowest average high temperature is December (42.6°F).

  • Average low temperature in December: 33.1°F

The month with the highest average low temperature is August (49.8°F).
The coldest month (with the lowest average low temperature) is December (33.1°F).

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Average pressure in December
Rochester, WA

Average pressure in December - Rochester, WA
  • Average pressure in December: 30.08"Hg

The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.02"Hg).

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Average wind speed in December
Rochester, WA

Average wind speed in December - Rochester, WA
  • Average wind speed in December: 4.2mph

The windiest months (with the highest average wind speed) are January, March and November (4.5mph).
The calmest month (with the lowest average wind speed) is September (3.6mph).

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Average humidity in December
Rochester, WA

Average humidity in December - Rochester, WA
  • Average humidity in December: 89%

The month with the highest relative humidity is November (90%).
The month with the lowest relative humidity is July (73%).

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Average rainfall in December
Rochester, WA

Average rainfall in December - Rochester, WA
  • Average rainfall in December: 3.74"

The wettest month (with the highest rainfall) is January (3.86").
The driest month (with the least rainfall) is July (0.35").

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Average rainfall days in December
Rochester, WA

Average rainfall days in December - Rochester, WA
  • Average rainfall days in December: 17.9 days

The month with the highest number of rainy days is March (19.8 days).
The month with the least rainy days is August (5.6 days).

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Average snowfall in December
Rochester, WA

Average snowfall in December - Rochester, WA
  • Average snowfall in December: 0.31"

The month with the highest snowfall is February (1.54").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in December
Rochester, WA

Average snowfall days in December - Rochester, WA
  • Average snowfall days in December: 1.2 days

The month with the highest number of snowfall days is February (2.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in December /
Average sunshine in December
Rochester, WA

Average daylight in December / Average sunshine in December - Rochester, WA
  • Average daylight in December: 8h and 4min

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 December: 3h and 3min

The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is December (Average sunshine: 3h and 30min).

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Average sunshine days in December
Rochester, WA

Average sunshine days in December - Rochester, WA
  • Average sunshine days in December: 10.8 days

The month with the most sunshine days is August (20.9 days).
The months with the least sunshine days are February and March (9.3 days).

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Average UV index in December
Rochester, WA

Average UV index in December - Rochester, WA
  • Average UV index in December: 2

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in December
Rochester, WA

Average cloud cover in December - Rochester, WA
  • Average cloud cover in December: 65

The month with the most cloud cover is January (Cloud cover 66).
The months with the least cloud cover are July and August (Cloud cover 38).

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Average visibility in December
Rochester, WA

Average visibility in December - Rochester, WA
  • Average visibility in December: 4mi

The month with the highest visibility is July (5mi).
The months with the lowest visibility are January, February, March, April, May, June, August, September, October, November and December (4mi).

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Rochester, Washington, USA

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