Annual mean 18°C · wettest around January · prevailing wind SW
Warmest
31.3 °C
Coldest
16.7 °C
Wettest
20%
Windiest
3.7 m/s
Prevailing
SW
2.8 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 Diamond Bar over the whole year is 18°C. August is the hottest month, with highs of about 31°C; January is the coldest, with lows of about 9°C. The rainy (wet) season in Diamond Bar runs from October to April, peaking in January with a 18% chance of rain on a given day. The dry season is May to September; July is the driest month, at 2%. Winds in Diamond Bar are highest in May, averaging 2.5 m/s (9 km/h), and lightest in November, at 1.5 m/s (5 km/h). The prevailing wind is from the SW. The clearest skies in Diamond Bar come in August, when the sky is typically 18% covered; May is the cloudiest month, at 46%.
Month by month Diamond Bar 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
17°C
9°C
15°C
18%
32%
1.6 m/s
53
1
85
February
18°C
9°C
15°C
17%
32%
1.9 m/s
55
5
80
March
19°C
10°C
16°C
16%
40%
2.2 m/s
60
6
81
April
22°C
13°C
19°C
10%
35%
2.4 m/s
77
16
74
May
22°C
15°C
20°C
9%
46%
2.5 m/s
82
17
72
June
26°C
18°C
25°C
5%
34%
2.5 m/s
70
47
40
July
30°C
20°C
29°C
2%
19%
2.5 m/s
39
71
12
August
31°C
20°C
30°C
7%
18%
2.3 m/s
31
73
7
September
29°C
19°C
28°C
6%
26%
2.1 m/s
51
60
20
October
26°C
16°C
24°C
11%
25%
1.8 m/s
71
45
42
November
22°C
12°C
20°C
12%
22%
1.5 m/s
81
16
73
December
18°C
9°C
15°C
16%
29%
1.5 m/s
60
2
87
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 Diamond Bar weather by season
Year round, Diamond Bar has days of about 17°C at their warmest in January, its coolest month, and 31°C in August, its warmest; the coolest hours of the day run from 9°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.
Diamond Bar weather in winterDecember to February
High 18°CLow 9°CRain 17%
Winter in Diamond Bar has typical daily highs of about 18°C and lows of about 9°C, with a 17% chance of rain on a given day.
Diamond Bar weather in springMarch to May
High 21°CLow 13°CRain 12%
Spring in Diamond Bar has typical daily highs of about 21°C and lows of about 13°C, with a 12% chance of rain on a given day.
Diamond Bar weather in summerJune to August
High 29°CLow 19°CRain 5%
Summer in Diamond Bar has typical daily highs of about 29°C and lows of about 19°C, with a 5% chance of rain on a given day.
Diamond Bar weather in autumnSeptember to November
High 26°CLow 15°CRain 10%
Autumn in Diamond Bar has typical daily highs of about 26°C and lows of about 15°C, with a 10% chance of rain on a given day.
When is the rainy season in Diamond Bar?
The rainy (wet) season in Diamond Bar runs from October to April, peaking in January with a 18% chance of rain on a given day. The dry season is May to September; July is the driest month, at 2%.
What time of year is Diamond Bar windiest?
Winds in Diamond Bar are highest in May, averaging 2.5 m/s (9 km/h), and lightest in November, at 1.5 m/s (5 km/h). The prevailing wind is from the SW.
What is the average temperature in Diamond Bar year round?
The average temperature in Diamond Bar over the whole year is 18°C. August is the hottest month, with highs of about 31°C; January is the coldest, with lows of about 9°C.