December weather forecast and climate
Commack, NY

The first month of the winter, December, is also a frosty month in Commack, New York, with average temperature varying between 36°F (2.2°C) and 43.3°F (6.3°C).

Temperature

In December, the average high-temperature slightly decreases, from a cool 51.4°F (10.8°C) in November, to a frosty 43.3°F (6.3°C). The average low-temperature, in Commack, is 36°F (2.2°C).

Humidity

In Commack, New York, the average relative humidity is 74%.

Rainfall

In Commack, in December, during 12 rainfall days, 3.78" (96mm) of precipitation is typically accumulated. Throughout the year, in Commack, there are 155.9 rainfall days, and 35.94" (913mm) of precipitation is accumulated.

Snowfall

January through March, November and December are months with snowfall in Commack. In Commack, during 2.5 snowfall days, 1.42" (36mm) of snow is typically accumulated. Throughout the year, there are 15.4 snowfall days, and 5.71" (145mm) of snow is accumulated.

Daylight

The month with the shortest days in Commack is December, with an average of 9.3h of daylight.

Sunshine

In December, the average sunshine is 4.9h.

UV index

January through March and December, with an average maximum UV index of 2, are months with the lowest UV index in Commack. A UV Index estimate of 2, and below, represents a low threat to health from the exposure to the Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 2 transform into the following instructions:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the temperature in December in Commack?

In December, in Commack, the average high-temperature is 43.3°F (6.3°C), and the average low-temperature is 36°F (2.2°C).

What is the average humidity in December in Commack?

In Commack, New York, the average relative humidity in December is 74%.

How many days does it rain in December in Commack?

In December, in Commack, New York, the rain falls for 12 days. Throughout December, 3.78" (96mm) of precipitation is accumulated.

How much does it snow in Commack in December?

In December, in Commack, it is snowing for 2.5 days. Throughout December, 1.42" (36mm) of snow is accumulated.

What is the month with the shortest days in Commack?

With an average of 9.3h of daylight, December has the shortest days of the year.

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

In Commack, the average length of the day in December is 9.3h.

How many hours of sunshine does Commack have in December?

The average sunshine in December in Commack is 4.9h.

When is the lowest UV index in Commack?

January through March and December, with an average maximum UV index of 2, are months with the lowest UV index in Commack, New York.

How high is the UV index in December in Commack?

In December, the average daily maximum UV index is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from the exposure to the Sun's UV radiation.
Average temperature in December - Commack, NY
  • Average high temperature in December: 6.3°C

The warmest month (with the highest average high temperature) is July (26.3°C).
The month with the lowest average high temperature is January (3.1°C).

  • Average low temperature in December: 2.2°C

The month with the highest average low temperature is August (22°C).
The coldest month (with the lowest average low temperature) is January (-1.7°C).

Average pressure in December - Commack, NY
  • Average pressure in December: 1018.1mbar

The month with the highest atmospheric pressure is November (1019.1mbar).
The month with the lowest atmospheric pressure is June (1013.6mbar).

Average wind speed in December - Commack, NY
  • Average wind speed in December: 19.9km/h

The windiest month (with the highest average wind speed) is January (20.6km/h).
The calmest month (with the lowest average wind speed) is July (13.3km/h).

Average humidity in December - Commack, NY
  • Average humidity in December: 74%

The month with the highest relative humidity is May (77%).
The month with the lowest relative humidity is November (71%).

Average rainfall in December - Commack, NY
  • Average rainfall in December: 96mm

The wettest month (with the highest rainfall) is July (100mm).
The driest month (with the least rainfall) is January (56mm).

Average rainfall days in December - Commack, NY
  • Average rainfall days in December: 12 days

The month with the highest number of rainy days is July (17.4 days).
The month with the least rainy days is January (7.8 days).

Average snowfall in December - Commack, NY
  • Average snowfall in December: 36mm

The month with the highest snowfall is March (47mm).
Months with the least snowfall are April, May, June, July, August, September and October (0mm).

Average snowfall days in December - Commack, NY
  • Average snowfall days in December: 2.5 days

The month with the highest number of snowfall days is February (4.8 days).
Months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in December / Average sunshine in December - Commack, NY
  • Average daylight in December: 9.3h

The month with the longest days is June (Average daylight: 15.1h).
The month with the shortest days is December (Average daylight: 9.3h).

  • Average sunshine in December: 4.9h

The month with the most sunshine is July (Average sunshine: 10.8h).
The month with the least sunshine is February (Average sunshine: 4.8h).

Average sunshine days in December - Commack, NY
  • Average sunshine days in December: 17 days

The month with the most sunshine days is November (19.4 days).
The month with the least sunshine days is July (11.4 days).

Average UV index in December - Commack, NY
  • Average UV index in December: 2

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, March and December (UV index 2).

Average cloud cover in December - Commack, NY
  • Average cloud cover in December: 48

The month with the most cloud cover is December (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 28).

Average visibility in December - Commack, NY
  • Average visibility in December: 9km

Months with the highest visibility are June, July, August, September, October and November (10km).
Months with the lowest visibility are January, February, March, April, May and December (9km).