Climate and monthly weather forecast
Mountainside, NJ

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Weather in January

January, like December, in Mountainside, New Jersey, is a wintry winter month, with an average temperature varying between 36°F (2.2°C) and 23.9°F (-4.5°C). The coldest temperatures occur during January, when averages reach a peak of 36°F (2.2°C) and a low of 23.9°F (-4.5°C). Weather in January »

Weather in February

The last month of the winter, February, is another cold month in Mountainside, New Jersey, with an average temperature fluctuating between 25.7°F (-3.5°C) and 39.2°F (4°C). Mountainside indicates an average high-temperature of a still icy 39.2°F (4°C) in February, showing minor variation from January's 36°F (2.2°C). Weather in February »

Weather in March

The first month of the spring, March, is a chilly month in Mountainside, New Jersey, with an average temperature fluctuating between 32.9°F (0.5°C) and 47.3°F (8.5°C). With the onset of March, Mountainside's weather sees a minor temperature rise, transitioning from a wintry 39.2°F (4°C) in February to a frosty 47.3°F (8.5°C). Weather in March »

Weather in April

April is a refreshing spring month in Mountainside, New Jersey, with an average temperature fluctuating between 43.3°F (6.3°C) and 59°F (15°C). The arrival of April brings a temperature shift, with the average high-temperature escalating from a chilly 47.3°F (8.5°C) in March to a refreshing 59°F (15°C). Weather in April »

Weather in May

The last month of the spring, May, is an agreeable month in Mountainside, New Jersey, with temperature in the range of an average high of 69.3°F (20.7°C) and an average low of 52.9°F (11.6°C). With the arrival of May, the average high-temperature transitions from a moderate 59°F (15°C) in April to a pleasant 69.3°F (20.7°C). Weather in May »

Weather in June

June, the first month of the summer in Mountainside, is a moderately hot month, with an average temperature ranging between max 77.5°F (25.3°C) and min 60.6°F (15.9°C). As June sets, the average high-temperature shows a slight increase, moving up from a pleasant 69.3°F (20.7°C) in May to a moderately hot 77.5°F (25.3°C). Weather in June »

Weather in July

July, the same as June, is another warm summer month in Mountainside, New Jersey, with an average temperature varying between 84.2°F (29°C) and 67.5°F (19.7°C). July brings the highest temperatures, with an average high of 84.2°F (29°C) and an average low of 67.5°F (19.7°C). The heat index for July is evaluated at a hot 91.4°F (33°C). Weather in July »

Weather in August

The last month of the summer, August, is also a moderately hot month in Mountainside, New Jersey, with an average temperature varying between 66.2°F (19°C) and 82°F (27.8°C). Mountainside registers an average high-temperature of a still moderately hot 82°F (27.8°C) at the commencement of August, closely related to the preceding month. Weather in August »

Weather in September

September, the first month of the autumn in Mountainside, is also a moderately hot month, with temperature in the range of an average low of 59.4°F (15.2°C) and an average high of 75.4°F (24.1°C). The commencement of September indicates a gentle shift in the average high-temperature, receding from August's warm 82°F (27.8°C) to a still moderately hot 75.4°F (24.1°C). Weather in September »

Weather in October

October, the same as September, is another enjoyable autumn month in Mountainside, New Jersey, with temperature in the range of an average high of 63.1°F (17.3°C) and an average low of 49.1°F (9.5°C). October brings a minor decrease, with the average high-temperature reducing from a warm 75.4°F (24.1°C) in September to an enjoyable 63.1°F (17.3°C). Weather in October »

Weather in November

The last month of the autumn, November, is another cool month in Mountainside, New Jersey, with an average temperature ranging between max 51.1°F (10.6°C) and min 38.1°F (3.4°C). November's onset brings a slight change in high-temperatures, falling from a refreshing 63.1°F (17.3°C) in October to a cool 51.1°F (10.6°C). Weather in November »

Weather in December

The first month of the winter, December, is also a wintry month in Mountainside, New Jersey, with an average temperature varying between 31.1°F (-0.5°C) and 42.3°F (5.7°C). December's arrival comes with a mild decrease in the average high-temperature, moving subtly from a cool 51.1°F (10.6°C) in November to an icy 42.3°F (5.7°C). Weather in December »
Updated: Feb 13, 2024 | Published by: Weather U.S. | Resources

Frequently asked questions

What are the coldest months in Mountainside?

Mountainside's January weather reaches an average high of 36°F (2.2°C) and an average low of 23.9°F (-4.5°C), making it the coldest month.

How many days does it rain in Mountainside?

Throughout the year, there are 160.7 rainfall days, and 30.12" (765mm) of precipitation is accumulated.

When does it snow in Mountainside?

January through May, October through December are months with snowfall in Mountainside, New Jersey.

How many days does it snow in Mountainside?

In Mountainside, New Jersey, during the entire year, snow falls for 25.4 days and aggregates up to 10.31" (262mm) of snow.

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

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

What are the most humid months in Mountainside?

February, October and December, with an average relative humidity of 78%, are most humid months.

What is the month with the least sunshine in Mountainside?

The month with the least sunshine in Mountainside, New Jersey, is February, with an average of 4.6h of sunshine.

When does it snow the most in Mountainside?

March is the month with the most snowfall. Snow falls for 5 days and accumulates 3.23" (82mm) of snow.

When is Daylight Saving Time (DST) in Mountainside?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Mountainside, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from EDT to EST.

What are the least humid months in Mountainside?

The months with the lowest humidity in Mountainside are April and August, with an average relative humidity of 73%.

When it does not snow in Mountainside?

In Mountainside, New Jersey, snow does not fall in June through September.

When are the longest days in Mountainside?

June has the longest days of the year in Mountainside, New Jersey, with an average of 15h and 0min of daylight.

What are the months with the highest UV index in Mountainside?

The months with the highest UV index in Mountainside, New Jersey, are June through August, with an average maximum UV index of 6.

What month is the hottest in Mountainside?

Mountainside experiences its highest temperatures in July, with an average peak of 84.2°F (29°C) and a low of 67.5°F (19.7°C).

What month has the most sunshine in Mountainside?

The month with the most sunshine in Mountainside is July, with an average of 10.5h of sunshine.

What is the driest month in Mountainside?

September is the month with the least rainfall in Mountainside, New Jersey. Rain falls for 12.9 days and accumulates 1.69" (43mm) of precipitation.

What is the wettest month in Mountainside?

December is the month with the most rainfall. Rain falls for 11.5 days and accumulates 3.19" (81mm) of precipitation.

What is the month with the shortest days in Mountainside?

With an average of 9h and 18min of daylight, December has the shortest days of the year in Mountainside, New Jersey.

Average temperature
Mountainside, NJ

Average temperature - Mountainside, NJ

The warmest month (with the highest average high temperature) is July (84.2°F).
The month with the lowest average high temperature is January (36°F).

The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (23.9°F).

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Average pressure
Mountainside, NJ

Average pressure - Mountainside, NJ

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

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Average wind speed
Mountainside, NJ

Average wind speed - Mountainside, NJ

The windiest month (with the highest average wind speed) is March (8.9mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).

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Average humidity
Mountainside, NJ

Average humidity - Mountainside, NJ

The months with the highest relative humidity are February, October and December (78%).
The months with the lowest relative humidity are April and August (73%).

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Average rainfall
Mountainside, NJ

Average rainfall - Mountainside, NJ

The wettest month (with the highest rainfall) is December (3.19").
The driest month (with the least rainfall) is September (1.69").

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Average rainfall days
Mountainside, NJ

Average rainfall days - Mountainside, NJ

The month with the highest number of rainy days is July (16.5 days).
The month with the least rainy days is January (9.5 days).

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Average snowfall
Mountainside, NJ

Average snowfall - Mountainside, NJ

The month with the highest snowfall is March (3.23").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days
Mountainside, NJ

Average snowfall days - Mountainside, NJ

The months with the highest number of snowfall days are January and February (7.3 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight / Average sunshine
Mountainside, NJ

Average daylight / Average sunshine - Mountainside, NJ

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).

The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

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Average sunshine days
Mountainside, NJ

Average sunshine days - Mountainside, NJ

The month with the most sunshine days is November (18.4 days).
The month with the least sunshine days is June (11.4 days).

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Average UV index
Mountainside, NJ

Average UV index - Mountainside, NJ

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

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Average cloud cover
Mountainside, NJ

Average cloud cover - Mountainside, NJ

The months with the most cloud cover are February, March and December (Cloud cover 48).
The months with the least cloud cover are July and August (Cloud cover 32).

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Average visibility
Mountainside, NJ

Average visibility - Mountainside, NJ

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).

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Mountainside, New Jersey, USA

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