Climate and monthly weather forecastAltadena, CA
Climate and monthly weather forecast
Weather in January
January, the same as December, is another enjoyable winter month in Altadena, California, with temperature in the range of an average high of 62.8°F (17.1°C) and an average low of 46.4°F (8°C). December's transformation into January witnesses an average high-temperature of a still refreshing 62.8°F (17.1°C), noting a minor change from the preceding month. Weather in January »Weather in February
The last month of the winter, February, is another refreshing month in Altadena, California, with temperature in the range of an average high of 62.4°F (16.9°C) and an average low of 45.7°F (7.6°C). February notes an average high-temperature of a still enjoyable 62.4°F (16.9°C), subtly differing from January's 62.8°F (17.1°C). Weather in February »Weather in March
The first month of the spring, March, is also an enjoyable month in Altadena, California, with temperature in the range of an average high of 66°F (18.9°C) and an average low of 46.9°F (8.3°C). March's commencement is accompanied by an average high-temperature of a still enjoyable 66°F (18.9°C), diverging marginally from February's 62.4°F (16.9°C). Weather in March »Weather in April
April is a pleasant spring month in Altadena, California, with an average temperature varying between 70°F (21.1°C) and 49.8°F (9.9°C). During April, Altadena records an average high-temperature of an agreeable 70°F (21.1°C), marking a slight divergence from March's 66°F (18.9°C). Weather in April »Weather in May
The last month of the spring, May, is also an agreeable month in Altadena, California, with temperature in the range of an average low of 53.2°F (11.8°C) and an average high of 73.2°F (22.9°C). April's transformation into May witnesses an average high-temperature of a still agreeable 73.2°F (22.9°C), noting a minor change from the preceding month. Weather in May »Weather in June
The first month of the summer, June, is a moderately hot month in Altadena, California, with an average temperature fluctuating between 79.9°F (26.6°C) and 57.7°F (14.3°C). The arrival of June signals a slight increase in the average high-temperature, moving from a pleasant 73.2°F (22.9°C) in May to a warm 79.9°F (26.6°C). Weather in June »Weather in July
July, like June, in Altadena, California, is another warm summer month, with an average temperature ranging between min 63.3°F (17.4°C) and max 85.1°F (29.5°C). Altadena records an average high-temperature of a still warm 85.1°F (29.5°C) in July, maintaining a close correlation with June's 79.9°F (26.6°C). Weather in July »Weather in August
The last month of the summer, August, is a hot month in Altadena, California, with an average temperature ranging between max 86.2°F (30.1°C) and min 64.4°F (18°C). The temperatures reach their highest averages in August, with highs of 86.2°F (30.1°C) and lows of 64.4°F (18°C). August's heat index is evaluated at a hot 87.8°F (31°C). Weather in August »Weather in September
September, the first month of the autumn in Altadena, is still a warm month, with an average temperature fluctuating between 62.6°F (17°C) and 84.6°F (29.2°C). The transition into September is marked with an average high-temperature of a warm 84.6°F (29.2°C), showing an insignificant shift from August's 86.2°F (30.1°C). Weather in September »Weather in October
October, like September, in Altadena, California, is another warm autumn month, with temperature in the range of an average high of 76.8°F (24.9°C) and an average low of 57.9°F (14.4°C). As September shifts into October, a minor alteration in temperatures is observed, with average highs reducing from a moderately hot 84.6°F (29.2°C) to a still warm 76.8°F (24.9°C). Weather in October »Weather in November
November, the last month of the autumn in Altadena, is also an agreeable month, with an average temperature fluctuating between 68.7°F (20.4°C) and 51.1°F (10.6°C). The arrival of November suggests a slight decrease in the average high-temperature, moving 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 an average temperature ranging between min 45.5°F (7.5°C) and max 61°F (16.1°C). Altadena witnesses the coldest weather in December, with temperatures averaging a high of 61°F (16.1°C) and a low of 45.5°F (7.5°C). Weather in December »Updated: Aug 4, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Throughout the year, there are 52 rainfall days, and 8.82" (224mm) of precipitation is accumulated.
February is the month with the most rainfall. Rain falls for 6.1 days and accumulates 1.81" (46mm) of precipitation.
The months with the least sunshine are February and December, with an average of 6.9h of sunshine.
March, May and June, with an average relative humidity of 56%, are most humid months.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.
The month with the least rainfall is June, when the rain falls for 1.3 days and typically collects 0.04" (1mm) of precipitation.
With an average of 14h and 24min of daylight, June has the longest days of the year.
June and July, with an average of 12.1h of sunshine, are months with the most sunshine.
The months with the highest UV index in Altadena are June through September, with an average maximum UV index of 6.
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 least humid month is November, with an average relative humidity of 46%.
December is the month when Altadena, California, sees the average lowest temperatures, with a high of 61°F (16.1°C) and a low of 45.5°F (7.5°C).
The month with the shortest days is December, with an average of 9h and 54min of daylight.
The month with the lowest UV index is December, with an average maximum UV index of 3.
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).
Average pressure
Altadena, CA
- Average pressure in January:
30.11"Hg - Average pressure in February:
30.05"Hg - Average pressure in March:
30.03"Hg - Average pressure in April:
29.96"Hg - Average pressure in May:
29.92"Hg - Average pressure in June:
29.88"Hg
- Average pressure in July:
29.91"Hg - Average pressure in August:
29.89"Hg - Average pressure in September:
29.89"Hg - Average pressure in October:
29.95"Hg - Average pressure in November:
30.03"Hg - Average pressure in December:
30.08"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed
Altadena, CA
- Average wind speed in January:
5.5mph - Average wind speed in February:
5.2mph - Average wind speed in March:
5.3mph - Average wind speed in April:
5.8mph - Average wind speed in May:
5.7mph - Average wind speed in June:
5.2mph
- Average wind speed in July:
4.9mph - Average wind speed in August:
4.6mph - Average wind speed in September:
4.4mph - Average wind speed in October:
4.7mph - Average wind speed in November:
5.1mph - Average wind speed in December:
5.5mph
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).
Average humidity
Altadena, CA
The months with the highest relative humidity are March, May and June (56%).
The month with the lowest relative humidity is November (46%).
Average rainfall
Altadena, CA
- Average rainfall in January:
1.5" - Average rainfall in February:
1.81" - Average rainfall in March:
1.1" - Average rainfall in April:
0.63" - Average rainfall in May:
0.28" - Average rainfall in June:
0.04"
- Average rainfall in July:
0.28" - Average rainfall in August:
0.16" - Average rainfall in September:
0.16" - Average rainfall in October:
0.24" - Average rainfall in November:
0.87" - Average rainfall in December:
1.77"
The wettest month (with the highest rainfall) is February (1.81").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days
Altadena, CA
- Average rainfall days in January:
5.7 days - Average rainfall days in February:
6.1 days - Average rainfall days in March:
7.5 days - Average rainfall days in April:
5.8 days - Average rainfall days in May:
3.5 days - Average rainfall days in June:
1.3 days
- Average rainfall days in July:
3.9 days - Average rainfall days in August:
2.3 days - Average rainfall days in September:
3 days - Average rainfall days in October:
2.9 days - Average rainfall days in November:
3.8 days - Average rainfall days in December:
6.2 days
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).
Average daylight / Average sunshine
Altadena, CA
- Average daylight in January:
10h and 12min - Average daylight in February:
11h and 0min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 6min - Average daylight in May:
14h and 0min - Average daylight in June:
14h and 24min
- Average daylight in July:
14h and 12min - Average daylight in August:
13h and 24min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 18min - Average daylight in November:
10h and 24min - Average daylight in December:
9h and 54min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in January:
7h and 0min - Average sunshine in February:
6h and 54min - Average sunshine in March:
8h and 54min - Average sunshine in April:
11h and 24min - Average sunshine in May:
11h and 42min - Average sunshine in June:
12h and 6min
- Average sunshine in July:
12h and 6min - Average sunshine in August:
12h and 0min - Average sunshine in September:
10h and 48min - Average sunshine in October:
8h and 36min - Average sunshine in November:
7h and 18min - Average sunshine in December:
6h and 54min
The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 54min).
Average sunshine days
Altadena, CA
- Average sunshine days in January:
24.5 days - Average sunshine days in February:
21.3 days - Average sunshine days in March:
22.6 days - Average sunshine days in April:
23.1 days - Average sunshine days in May:
25.4 days - Average sunshine days in June:
27.2 days
- Average sunshine days in July:
24.3 days - Average sunshine days in August:
26.2 days - Average sunshine days in September:
25.6 days - Average sunshine days in October:
26.6 days - Average sunshine days in November:
24.8 days - Average sunshine days in December:
23.5 days
The month with the most sunshine days is June (27.2 days).
The month with the least sunshine days is February (21.3 days).
Average UV index
Altadena, CA
The months with the highest UV index are June, July, August and September (UV index 6).
The month with the lowest UV index is December (UV index 3).
Average cloud cover
Altadena, CA
The month with the most cloud cover is March (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility
Altadena, CA
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
