December weather forecast
Heidelberg, PA

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Weather in December

December, the first month of the winter in Heidelberg, is also a wintry month, with an average temperature varying between 28.4°F (-2°C) and 39.7°F (4.3°C).

Temperature

December indicates a shift in the average high-temperature, from November's frosty 49.3°F (9.6°C) to an icy 39.7°F (4.3°C). Heidelberg's average low-temperature for the month of December records at a freezing cold 28.4°F (-2°C).

Humidity

In Heidelberg, the average relative humidity in December is 83%.

Rainfall

In December, in Heidelberg, the rain falls for 8.2 days. Throughout December, 0.87" (22mm) of precipitation is accumulated. Throughout the year, there are 132.6 rainfall days, and 11.5" (292mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, November and December. In Heidelberg, in December, snow falls for 6.4 days, with typically accumulated 0.59" (15mm) of snow. Throughout the year, in Heidelberg, there are 32.5 snowfall days, and 3.66" (93mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 18min of daylight.
On the first day of December in Heidelberg, sunrise is at 7:24 am and sunset at 4:54 pm. On the last day of the month, sunrise is at 7:43 am and sunset at 5:04 pm EST.

Sunshine

In Heidelberg, the average sunshine in December is 3.4h.

UV index

With an average maximum UV index of 1, December is the month with the lowest UV index. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A maximum daily UV index of 1 during December morphs into the following directions:
Extended sunlight exposure does not pose significant problems for most people, except for children, infants, and people with fair skin who always need shielding. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Notice! The UV radiation of the Sun can be intensified nearly twofold due to the reflective quality of snow.

Frequently asked questions

Is December cold?

The average high-temperature, in December, in Heidelberg, is 39.7°F (4.3°C), while the average low-temperature is 28.4°F (-2°C). In August, the average heat index (a.k.a. 'feels like', 'apparent temperature'), which factors the actual air temperature with the relative humidity, is appraised at 87.8°F (31°C).

What is the average humidity in December?

In Heidelberg, the average relative humidity in December is 83%.

How many days does it rain in December?

In Heidelberg, during December, the rain falls for 8.2 days and regularly aggregates up to 0.87" (22mm) of precipitation.

How much does it snow in December?

In December, it is snowing for 6.4 days. Throughout December, 0.59" (15mm) of snow is accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 18min of daylight.

How many hours of daylight does Heidelberg have in December?

The average day length in December is 9h and 21min.

When are sunrise and sunset in December?

On the first day of December, sunrise is at 7:24 am and sunset at 4:54 pm. On the last day of the month, sunrise is at 7:43 am and sunset at 5:04 pm EST.

How long on average sun shines in December?

The average sunshine duration in December is 3.4h.

What is the month with the lowest UV index?

With an average maximum UV index of 1, December is the month with the lowest UV index.

What is the UV index reading in December?

The average daily maximum UV index in December is 1. A UV Index reading of 2, and below, represents a minimal hazard to health from unsafe 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 December
Heidelberg, PA

Average temperature in December - Heidelberg, PA
  • Average high temperature in December: 39.7°F

The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (33.4°F).

  • Average low temperature in December: 28.4°F

The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is January (21°F).

Average pressure in December
Heidelberg, PA

Average pressure in December - Heidelberg, PA
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).

Average wind speed in December
Heidelberg, PA

Average wind speed in December - Heidelberg, PA
  • Average wind speed in December: 7.3mph

The windiest month (with the highest average wind speed) is January (7.9mph).
The calmest months (with the lowest average wind speed) are July and August (4.7mph).

Average humidity in December
Heidelberg, PA

Average humidity in December - Heidelberg, PA
  • Average humidity in December: 83%

The month with the highest relative humidity is February (85%).
The months with the lowest relative humidity are July and August (75%).

Average rainfall in December
Heidelberg, PA

Average rainfall in December - Heidelberg, PA
  • Average rainfall in December: 0.87"

The wettest month (with the highest rainfall) is July (1.34").
The driest month (with the least rainfall) is November (0.67").

Average rainfall days in December
Heidelberg, PA

Average rainfall days in December - Heidelberg, PA
  • Average rainfall days in December: 8.2 days

The month with the highest number of rainy days is July (15.6 days).
The month with the least rainy days is February (6.4 days).

Average snowfall in December
Heidelberg, PA

Average snowfall in December - Heidelberg, PA
  • Average snowfall in December: 0.59"

The month with the highest snowfall is February (0.98").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
Heidelberg, PA

Average snowfall days in December - Heidelberg, PA
  • Average snowfall days in December: 6.4 days

The month with the highest number of snowfall days is January (9.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Heidelberg, PA

Average daylight in December / Average sunshine in December - Heidelberg, PA
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 3h and 2min

The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).

Average sunshine days in December
Heidelberg, PA

Average sunshine days in December - Heidelberg, PA
  • Average sunshine days in December: 18.5 days

The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is May (12.2 days).

Average UV index in December
Heidelberg, PA

Average UV index in December - Heidelberg, PA
  • Average UV index in December: 1

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in December
Heidelberg, PA

Average cloud cover in December - Heidelberg, PA
  • Average cloud cover in December: 64

The month with the most cloud cover is January (Cloud cover 68).
The month with the least cloud cover is August (Cloud cover 33).

Average visibility in December
Heidelberg, PA

Average visibility in December - Heidelberg, PA
  • Average visibility in December: 5mi

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

Heidelberg, Pennsylvania, USA

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