Annual mean 18°C · wettest around January · prevailing wind SW
Warmest
29.8 °C
Coldest
15.2 °C
Wettest
17%
Windiest
4.0 m/s
Prevailing
SW
3.3 m/s average
When this place is good five ratings · thirty-six ten-day sections · click a cell to read it
never good
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Every reading
bars actual · line feels-like, °Cchance of rain, %wind speed, m/ssky covered, %
The average temperature in Altadena over the whole year is 18°C. August is the hottest month, with highs of about 29°C; January is the coldest, with lows of about 8°C. Altadena has no sharply defined rainy season: the chance of rain on a given day runs from 3% in July, the driest month, to 15% in January, the wettest. Winds in Altadena are highest in April, averaging 3.1 m/s (11 km/h), and lightest in December, at 2.0 m/s (7 km/h). The prevailing wind is from the SW. The clearest skies in Altadena come in August, when the sky is typically 15% covered; May is the cloudiest month, at 37%.
Month by month Altadena climate by month: average temperatures year round · click a month to read it
Month
High
Low
Feels like
Chance of rain
Cloud
Wind
Being outside
Sun
Walking
January
16°C
8°C
13°C
15%
25%
2.2 m/s
42
1
78
February
17°C
9°C
13°C
15%
26%
2.5 m/s
45
3
76
March
17°C
10°C
14°C
15%
32%
2.9 m/s
49
4
78
April
20°C
12°C
17°C
10%
27%
3.1 m/s
69
11
76
May
21°C
15°C
19°C
9%
37%
3.1 m/s
77
15
73
June
25°C
18°C
24°C
4%
30%
3.1 m/s
73
39
48
July
28°C
20°C
28°C
3%
17%
3.0 m/s
51
60
22
August
29°C
20°C
28°C
6%
15%
2.8 m/s
44
68
15
September
28°C
18°C
27°C
5%
21%
2.6 m/s
59
55
28
October
25°C
15°C
23°C
8%
20%
2.3 m/s
75
37
51
November
20°C
11°C
18°C
10%
17%
2.1 m/s
72
11
76
December
16°C
9°C
14°C
14%
23%
2.0 m/s
49
1
81
High and low are the warmest and coolest of four readings a day — midnight, 6am, noon and 6pm — so a true overnight low can sit a degree or two under them. Chance of rain, cloud and wind are the day’s average; feels-like and the three ratings (each out of 100: Good from 55, Ideal from 80) are read at midday.
Seasons, and the year in short Altadena weather by season
Year round, Altadena has days of about 16°C at their warmest in January, its coolest month, and 29°C in August, its warmest; the coolest hours of the day run from 8°C to 20°C through the year, and the average temperature over the year is 18°C around the clock. Rain is most likely around January and least likely around July. Every figure here is a decade of observations blended into one representative year, so it reads as what this date is usually like, not a forecast for one particular day.
Altadena weather in winterDecember to February
High 16°CLow 9°CRain 15%
Winter in Altadena has typical daily highs of about 16°C and lows of about 9°C, with a 15% chance of rain on a given day.
Altadena weather in springMarch to May
High 20°CLow 12°CRain 11%
Spring in Altadena has typical daily highs of about 20°C and lows of about 12°C, with a 11% chance of rain on a given day.
Altadena weather in summerJune to August
High 28°CLow 20°CRain 4%
Summer in Altadena has typical daily highs of about 28°C and lows of about 20°C, with a 4% chance of rain on a given day.
Altadena weather in autumnSeptember to November
High 24°CLow 15°CRain 8%
Autumn in Altadena has typical daily highs of about 24°C and lows of about 15°C, with a 8% chance of rain on a given day.
When is the rainy season in Altadena?
Altadena has no sharply defined rainy season: the chance of rain on a given day runs from 3% in July, the driest month, to 15% in January, the wettest.
What time of year is Altadena windiest?
Winds in Altadena are highest in April, averaging 3.1 m/s (11 km/h), and lightest in December, at 2.0 m/s (7 km/h). The prevailing wind is from the SW.
What is the average temperature in Altadena year round?
The average temperature in Altadena over the whole year is 18°C. August is the hottest month, with highs of about 29°C; January is the coldest, with lows of about 8°C.