Shelter Island Heights
New York, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
Shelter Island Heights, NY

The first month of the winter, December, is still a chilly month in Shelter Island Heights, New York, with average temperature fluctuating between 45°F (7.2°C) and 37.9°F (3.3°C).

Temperature

In Shelter Island Heights, the average high-temperature slightly decreases, from a fresh 52.7°F (11.5°C) in November, to a chilly 45°F (7.2°C). In December, the average low-temperature is 37.9°F (3.3°C).

Humidity

In December, the average relative humidity is 74%.

Rainfall

December is the month with the most rainfall. Rain falls for 12.8 days and accumulates 3.82" (97mm) of precipitation.

Snowfall

Months with snowfall are January through March, November and December. In December, it is snowing for 2.3 days. Throughout December, 0.91" (23mm) of snow is accumulated. In Shelter Island Heights, during the entire year, snow falls for 13.9 days, and aggregates up to 6.61" (168mm) of snow.

Ocean temperature

In Shelter Island Heights, the average water temperature is 48.9°F (9.4°C).
Note: Swimming in 48.9°F (9.4°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

Daylight

With an average of 9.3h of daylight, December has the shortest days of the year in Shelter Island Heights.

Sunshine

With an average of 4.6h of sunshine, December has the least sunshine of the year.

UV index

January through March and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health vulnerability from unsafe exposure to the UV radiation for the average person.
Note: In December, the average maximum UV index of 2 translate into the following recommendations:
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 Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. 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 Shelter Island Heights?

In Shelter Island Heights, in December, the average high-temperature is 45°F (7.2°C), and the average low-temperature is 37.9°F (3.3°C).

What is the average humidity in December in Shelter Island Heights?

In Shelter Island Heights, the average relative humidity in December is 74%.

How many days does it rain in December in Shelter Island Heights?

In December, in Shelter Island Heights, New York, the rain falls for 12.8 days. Throughout December, 3.82" (97mm) of precipitation is accumulated.

What is the rainiest month in Shelter Island Heights?

December is the month with the most rainfall in Shelter Island Heights. Rain falls for 12.8 days and accumulates 3.82" (97mm) of precipitation.

How much does it snow in Shelter Island Heights in December?

In Shelter Island Heights, New York, during December, snow falls for 2.3 days and regularly aggregates up to 0.91" (23mm) of snow.

How cold is the water in December in Shelter Island Heights?

In December, the average ocean temperature in Shelter Island Heights, New York, is 48.9°F (9.4°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the month with the shortest days in Shelter Island Heights?

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

How many hours of daylight does Shelter Island Heights have in December?

The average length of the day in December is 9.3h.

What is the month with the least sunshine in Shelter Island Heights?

December has the least sunshine of the year in Shelter Island Heights, New York, with an average of 4.6h of sunshine.

How many hours of sunshine does Shelter Island Heights have in December?

In December, the average sunshine in Shelter Island Heights is 4.6h.

When is the lowest UV index in Shelter Island Heights?

January through March and December, with an average maximum UV index of 2, are months with the lowest UV index in Shelter Island Heights.

What is the UV index reading in December in Shelter Island Heights?

In December, the average daily maximum UV index is 2. A UV Index reading of 2, and below, represents a low health risk from unsafe exposure to the Sun's UV rays.
Average temperature in December - Shelter Island Heights, NY
  • Average high temperature in December: 45°F

The warmest month (with the highest average high temperature) is August (75.9°F).
The month with the lowest average high temperature is January (38.8°F).

  • Average low temperature in December: 37.9°F

The month with the highest average low temperature is August (71.2°F).
The coldest month (with the lowest average low temperature) is January (31.3°F).

Average humidity in December - Shelter Island Heights, NY
  • Average humidity in December: 74%

Months with the highest relative humidity are May and June (81%).
The month with the lowest relative humidity is November (72%).

Average rainfall in December - Shelter Island Heights, NY
  • Average rainfall in December: 3.82"

The wettest month (with the highest rainfall) is December (3.82").
The driest month (with the lowest rainfall) is September (2.17").

Average rainfall days in December - Shelter Island Heights, NY
  • Average rainfall days in December: 12.8 days

The month with the highest number of rainy days is May (15.3 days).
The month with the lowest number of rainy days is January (9.1 days).

Average snowfall in December - Shelter Island Heights, NY
  • Average snowfall in December: 0.91"

The month with the highest snowfall is March (2.36").
Months with the lowest snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in December - Shelter Island Heights, NY
  • Average snowfall days in December: 2.3 days

The month with the highest number of snowfall days is January (4.2 days).
Months with the lowest number of snowfall days are May, June, July, August, September and October (0 days).

Average sea temperature in December - Shelter Island Heights, NY
  • Average sea temperature in December: 48.9°F

The best month for swimming (with the highest average sea temperature) is August (72.1°F).
The coldest month (with the lowest average sea temperature) is February (38.8°F).

Average daylight in December / Average sunshine in December - Shelter Island Heights, NY
  • Average daylight in December: 9.3h

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

  • Average sunshine in December: 4.6h

Months with most sunshine are July and August (Average sunshine: 10.6h).
The month with least sunshine is December (Average sunshine: 4.6h).

Average UV index in December - Shelter Island Heights, 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).