January weather forecast
Rock Mill, NJ

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Weather in January

January, the same as December, is a wintry winter month in Rock Mill, New Jersey, with an average temperature ranging between max 36.5°F (2.5°C) and min 23.5°F (-4.7°C).

Temperature

January is the coldest month, with the temperature often reaching an average high of 36.5°F (2.5°C) and an average low of 23.5°F (-4.7°C).

Humidity

The average relative humidity in January in Rock Mill is 76%.

Rainfall

In Rock Mill, New Jersey, during January, the rain falls for 5.8 days and regularly aggregates up to 0.47" (12mm) of precipitation. Throughout the year, in Rock Mill, there are 107.3 rainfall days, and 8.82" (224mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Rock Mill are January through May, November and December. In January, in Rock Mill, it is snowing for 3.7 days. Throughout January, 0.47" (12mm) of snow is accumulated. Throughout the year, there are 15.5 snowfall days, and 2.76" (70mm) of snow is accumulated.

Daylight

The average length of the day in January in Rock Mill is 9h and 41min.
On the first day of January in Rock Mill, sunrise is at 7:22 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 5:15 pm EST.

Sunshine

The average sunshine in January is 5.1h.

UV index

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation for the average person.
Note: The maximum daily UV index of 2 in January converts into the following recommendations:
Prolonged sun exposure generally does not trouble most people. However, it is vital to ensure protection for babies, children, and individuals with sensitive skin. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.
Updated: Feb 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the coldest months in Rock Mill?

In Rock Mill, January is the coldest month, with temperatures averaging a high of 36.5°F (2.5°C) and a low of 23.5°F (-4.7°C).

How cold is January in Rock Mill?

The high-temperature, in January, in Rock Mill, records 36.5°F (2.5°C), while the low-temperature is 23.5°F (-4.7°C).

What is the average humidity in January in Rock Mill?

In January, the average relative humidity in Rock Mill is 76%.

How many days does it rain in January in Rock Mill?

In January, in Rock Mill, the rain falls for 5.8 days. Throughout January, 0.47" (12mm) of precipitation is accumulated.

How many days does it snow in January in Rock Mill?

In Rock Mill, New Jersey, in January, during 3.7 snowfall days, 0.47" (12mm) of snow is typically accumulated.

How many hours of daylight does Rock Mill have in January?

In Rock Mill, the average day length in January is 9h and 41min.

What time are sunrise and sunset in January in Rock Mill?

In January, on the first day of the month, sunrise is at 7:22 am and sunset at 4:42 pm. On the last day of the month, in Rock Mill, New Jersey, sunrise is at 7:09 am and sunset at 5:15 pm EST.

How long on average sun shines in January in Rock Mill?

The average sunshine duration in January in Rock Mill is 5.1h.

When is the lowest UV index in Rock Mill?

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

How high is the UV index in January in Rock Mill?

In January, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a low health risk from exposure to the Sun's 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 January
Rock Mill, NJ

Average temperature in January - Rock Mill, NJ
  • Average high temperature in January: 36.5°F

The warmest month (with the highest average high temperature) is July (84.6°F).
The month with the lowest average high temperature is January (36.5°F).

  • Average low temperature in January: 23.5°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (23.5°F).

Average pressure in January
Rock Mill, NJ

Average pressure in January - Rock Mill, NJ
  • Average pressure in January: 30.08"Hg

The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in January
Rock Mill, NJ

Average wind speed in January - Rock Mill, NJ
  • Average wind speed in January: 8.4mph

The windiest month (with the highest average wind speed) is March (8.6mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

Average humidity in January
Rock Mill, NJ

Average humidity in January - Rock Mill, NJ
  • Average humidity in January: 76%

The months with the highest relative humidity are February and October (79%).
The month with the lowest relative humidity is April (74%).

Average rainfall in January
Rock Mill, NJ

Average rainfall in January - Rock Mill, NJ
  • Average rainfall in January: 0.47"

The wettest month (with the highest rainfall) is July (1.18").
The driest month (with the least rainfall) is September (0.35").

Average rainfall days in January
Rock Mill, NJ

Average rainfall days in January - Rock Mill, NJ
  • Average rainfall days in January: 5.8 days

The month with the highest number of rainy days is July (12.9 days).
The month with the least rainy days is November (5.5 days).

Average snowfall in January
Rock Mill, NJ

Average snowfall in January - Rock Mill, NJ
  • Average snowfall in January: 0.47"

The month with the highest snowfall is March (0.75").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in January
Rock Mill, NJ

Average snowfall days in January - Rock Mill, NJ
  • Average snowfall days in January: 3.7 days

The month with the highest number of snowfall days is February (4.3 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in January /
Average sunshine in January
Rock Mill, NJ

Average daylight in January / Average sunshine in January - Rock Mill, NJ
  • Average daylight in January: 9h and 4min

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 January: 5h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).

Average sunshine days in January
Rock Mill, NJ

Average sunshine days in January - Rock Mill, NJ
  • Average sunshine days in January: 22.3 days

The month with the most sunshine days is November (22.7 days).
The month with the least sunshine days is July (13.6 days).

Average UV index in January
Rock Mill, NJ

Average UV index in January - Rock Mill, NJ
  • Average UV index in January: 2

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

Average cloud cover in January
Rock Mill, NJ

Average cloud cover in January - Rock Mill, NJ
  • Average cloud cover in January: 44

The months with the most cloud cover are February and December (Cloud cover 48).
The months with the least cloud cover are July and August (Cloud cover 33).

Average visibility in January
Rock Mill, NJ

Average visibility in January - Rock Mill, NJ
  • Average visibility in January: 6mi

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

Rock Mill, New Jersey, USA

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