Monthly weather forecast and climate
Altadena, CA

Weather in January

January, like December, in Altadena, California, is another enjoyable winter month, with average temperature varying between 46.4°F (8°C) and 62.8°F (17.1°C). In January, the average high-temperature is relatively the same as in December - a still enjoyable 62.8°F (17.1°C). Weather in January »

Weather in February

The last month of the winter, February, is also an enjoyable month in Altadena, California, with average temperature varying between 45.7°F (7.6°C) and 62.4°F (16.9°C). In Altadena, the average high-temperature in February is almost the same as in January - a still enjoyable 62.4°F (16.9°C). Weather in February »

Weather in March

The first month of the spring, March, is still a comfortable month in Altadena, California, with average temperature varying between 66°F (18.9°C) and 46.9°F (8.3°C). In Altadena, California, the average high-temperature is relatively the same as in February - a still enjoyable 66°F (18.9°C). Weather in March »

Weather in April

April in Altadena, California, is a pleasant spring month, with average temperature fluctuating between 70°F (21.1°C) and 49.8°F (9.9°C). In April, the average high-temperature is relatively the same as in March - an agreeable 70°F (21.1°C). Weather in April »

Weather in May

The last month of the spring, May, is also an agreeable month in Altadena, California, with average temperature varying between 73.2°F (22.9°C) and 53.2°F (11.8°C). In Altadena, the average high-temperature in May is relatively the same as in April - a still agreeable 73.2°F (22.9°C). Weather in May »

Weather in June

The first month of the summer, June, is a moderately hot month in Altadena, California, with average temperature varying between 79.9°F (26.6°C) and 57.7°F (14.3°C). In June, the average high-temperature marginally rises, from an agreeable 73.2°F (22.9°C) in May, to a moderately hot 79.9°F (26.6°C). Weather in June »

Weather in July

July, the same as June, is a moderately hot summer month in Altadena, California, with average temperature ranging between min 63.3°F (17.4°C) and max 85.1°F (29.5°C). In Altadena, the average high-temperature is relatively the same as in June - a still warm 85.1°F (29.5°C). Weather in July »

Weather in August

The last month of the summer, August, is a hot month in Altadena, California, with average temperature varying between 64.4°F (18°C) and 86.2°F (30.1°C). August is the warmest month, with an average high-temperature of 86.2°F (30.1°C) and an average low-temperature of 64.4°F (18°C). The average heat index is calculated to a hot 87.6°F (30.9°C). Weather in August »

Weather in September

September, the first month of the autumn, in Altadena, is still a warm month, with average temperature ranging between max 84.6°F (29.2°C) and min 62.6°F (17°C). In September, the average high-temperature is practically the same as in August - a moderately hot 84.6°F (29.2°C). Weather in September »

Weather in October

October, like September, in Altadena, California, is a moderately hot autumn month, with average temperature varying between 76.8°F (24.9°C) and 57.9°F (14.4°C). In Altadena, the average high-temperature in October marginally drops, from 84.6°F (29.2°C) in September, to a still moderately hot 76.8°F (24.9°C). Weather in October »

Weather in November

The last month of the autumn, November, is another pleasant month in Altadena, California, with average temperature ranging between min 51.1°F (10.6°C) and max 68.7°F (20.4°C). In November, the average high-temperature slightly decreases, from a moderately hot 76.8°F (24.9°C) in October, to a pleasant 68.7°F (20.4°C). Weather in November »

Weather in December

December, the first month of the winter, in Altadena, is still a comfortable month, with average temperature fluctuating between 45.5°F (7.5°C) and 61°F (16.1°C). December is the coldest month, with an average high-temperature of 61°F (16.1°C) and an average low-temperature of 45.5°F (7.5°C). Weather in December »
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FAQ

How many days does it rain in Altadena?

Throughout the year, in Altadena, there are 52 rainfall days, and 8.82" (224mm) of precipitation is accumulated.

What is the rainiest month in Altadena?

The month with the most rainfall in Altadena is February when the rain falls for 6.1 days and typically aggregates up to 1.81" (46mm) of precipitation.

What is the month with the least sunshine in Altadena?

February and December, with an average of 6.9h of sunshine, are months with the least sunshine in Altadena, California.

What is the most humid month in Altadena?

March, May and June, with an average relative humidity of 56%, are most humid months.

What is the driest month in Altadena?

The month with the least rainfall in Altadena is June when the rain falls for 1.3 days and typically collects 0.04" (1mm) of precipitation.

When are the longest days in Altadena?

June has the longest days of the year in Altadena, California, with an average of 14.4h of daylight.

What is the month with the most sunshine in Altadena?

Months with the most sunshine are June and July, with an average of 12.1h of sunshine.

What is the month with the highest UV index in Altadena?

Months with the highest UV index in Altadena are June through September, with an average maximum UV index of 6.

What is the warmest month in Altadena?

August is the warmest month in Altadena, California, with an average high-temperature of 86.2°F (30.1°C) and an average low-temperature of 64.4°F (18°C).

What is the least humid month in Altadena?

With an average relative humidity of 46%, November is the least humid month in Altadena.

What is the coldest month in Altadena?

December is the coldest month in Altadena, California, with an average high-temperature of 61°F (16.1°C) and an average low-temperature of 45.5°F (7.5°C).

What is the month with the shortest days in Altadena?

The month with the shortest days is December, with an average of 9.9h of daylight.

When is the lowest UV index in Altadena?

With an average maximum UV index of 3, December is the month with the lowest UV index.

Average temperature
Altadena, CA

Average temperature - Altadena, CA

The warmest month (with the highest average high temperature) is August (86.2°F).
The month with the lowest average high temperature is December (61°F).

The month with the highest average low temperature is August (64.4°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).

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Average pressure
Altadena, CA

Average pressure - Altadena, CA

The month with the highest atmospheric pressure is January (30.11").
The month with the lowest atmospheric pressure is June (29.88").

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Average wind speed
Altadena, CA

Average wind speed - Altadena, CA

The windiest month (with the highest average wind speed) is April (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).

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Average humidity
Altadena, CA

Average humidity - Altadena, CA

Months with the highest relative humidity are March, May and June (56%).
The month with the lowest relative humidity is November (46%).

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Average rainfall
Altadena, CA

Average rainfall - Altadena, CA

The wettest month (with the highest rainfall) is February (1.81").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days
Altadena, CA

Average rainfall days - Altadena, CA

The month with the highest number of rainy days is March (7.5 days).
The month with the least rainy days is June (1.3 days).

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Average daylight / Average sunshine
Altadena, CA

Average daylight / Average sunshine - Altadena, CA

The month with the longest days is June (Average daylight: 14.4h).
The month with the shortest days is December (Average daylight: 9.9h).

Months with the most sunshine are June and July (Average sunshine: 12.1h).
Months with the least sunshine are February and December (Average sunshine: 6.9).

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Average sunshine days
Altadena, CA

Average sunshine days - Altadena, CA

The month with the most sunshine days is June (27.2 days).
The month with the least sunshine days is February (21.3 days).

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Average visibility
Altadena, CA

Average visibility - Altadena, CA

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

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