, near the coast of Suisun Bay, a northern extension of San Francisco Bay. Nearby are cities such as Pleasant Hill, Pacheco, Walnut Creek, Clayton, Pittsburg, Bay Point and Clyde.
, from December to February, is mild, with periods of bad weather alternating with sunny periods. In the latter, fog can form at night.
On average, there are 9 days on which the minimum temperature is equal to or below freezing, and that usually happens from November through February. However, the temperature generally drops slightly below freezing. In December 1990, it dropped to -5.5 °C (22 °F).
, from June to September, is hot and sunny, with quite cool nights. There can be very hot periods, in which the wind blows from the desert, but even in these cases, the temperature generally drops below 20 °C (68 °F) during the night, thanks to the breeze coming from the bay.
On average, there are 9 days with a maximum temperature equal to or above 37.8 °C (100 °F), and that usually happens from June through September. In July 2006, it reached 44.4 °C (112 °F). However, short hot periods, in which the wind blows from the desert and the temperature exceeds 32 °C (90 °F), can also occur in April, May and October.
The best times to visit Concord are spring and autumn, and in particular the months of April, May and October. It can get very hot at times, but less often than in summer.
. Here are the average temperatures.
January, the coldest month of the year, is generally a mild month. The average temperature is of
9.7 °C, with a minimum of
5.1 °C and a maximum of
14.2 °C.
On the coldest nights of the month, the temperature usually drops to around
0 °C.
On the warmest days of the month, the temperature usually reaches around
18.5 °C.
Precipitation amounts to
80 mm, distributed over 9 days.
The day lasts on average 9 hours and 55 minutes.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is of
9.6 kph.
The average sea temperature is of
12.4 °C. Therefore, the sea is very cold for swimming.
February is generally a mild month. The average temperature is of
11.6 °C, with a minimum of
6.6 °C and a maximum of
16.7 °C.
On the coldest nights of the month, the temperature usually drops to around
1.5 °C.
On the warmest days of the month, the temperature usually reaches around
21.5 °C.
Precipitation amounts to
80 mm, distributed over 9 days.
The day lasts on average 10 hours and 50 minutes.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is of
10.1 kph.
The average sea temperature is of
12.2 °C. Therefore, the sea is very cold for swimming.
March is generally a mild month. The average temperature is of
13.7 °C, with a minimum of
8.1 °C and a maximum of
19.3 °C.
On the coldest nights of the month, the temperature usually drops to around
3 °C.
On the warmest days of the month, the temperature usually reaches around
25 °C.
Precipitation amounts to
55 mm, distributed over 9 days.
The day lasts on average 12 hours and 0 minutes.
The average humidity is 64%.
The average wind speed is of
12.2 kph.
The average sea temperature is of
12.2 °C. Therefore, the sea is very cold for swimming.
April is generally a very mild month. The average temperature is of
15.6 °C, with a minimum of
9.5 °C and a maximum of
21.8 °C.
On the coldest nights of the month, the temperature usually drops to around
4 °C.
On the warmest days of the month, the temperature usually reaches around
29.5 °C.
Precipitation amounts to
30 mm, distributed over 5 days.
The day lasts on average 13 hours and 10 minutes.
The average humidity is 58%.
The average wind speed is of
14.7 kph.
The average sea temperature is of
11.8 °C. Therefore, the sea is very cold for swimming.
May is generally a warm month. However, there are remarkable differences between night and day. The average temperature is of
18.5 °C, with a minimum of
11.7 °C and a maximum of
25.3 °C.
On the coldest nights of the month, the temperature usually drops to around
8.5 °C.
On the warmest days of the month, the temperature usually reaches around
34 °C.
Precipitation amounts to
15 mm, distributed over 3 days.
The day lasts on average 14 hours and 20 minutes. So the days are long.
The average humidity is 54%.
The average wind speed is of
16.3 kph.
The average sea temperature is of
11.8 °C. Therefore, the sea is very cold for swimming.
June is generally a warm month. However, there are remarkable differences between night and day. The average temperature is of
21.5 °C, with a minimum of
13.9 °C and a maximum of
29 °C.
On the coldest nights of the month, the temperature usually drops to around
11 °C.
On the warmest days of the month, the temperature usually reaches around
38.5 °C.
Precipitation amounts to only
5 mm, and all occurs in one day.
The day lasts on average 14 hours and 50 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
The average humidity is 50%.
The average wind speed is of
17.9 kph.
The average sea temperature is of
12.2 °C. Therefore, the sea is very cold for swimming.
July is generally a warm to hot month. However, there are remarkable differences between night and day. The average temperature is of
23 °C, with a minimum of
14.8 °C and a maximum of
31.1 °C.
On the coldest nights of the month, the temperature usually drops to around
12.5 °C.
On the warmest days of the month, the temperature usually reaches around
39.5 °C.
Precipitation amounts to only
0 mm, so on average it never rains in the whole month.
The day lasts on average 14 hours and 30 minutes. So the days are long.
The average humidity is 51%.
The average wind speed is of
18 kph.
The average sea temperature is of
13.1 °C. Therefore, the sea is very cold for swimming.
August, the warmest month of the year, is generally a warm to hot month. However, there are remarkable differences between night and day. The average temperature is of
23.1 °C, with a minimum of
15.2 °C and a maximum of
31.1 °C.
On the coldest nights of the month, the temperature usually drops to around
12.5 °C.
On the warmest days of the month, the temperature usually reaches around
39 °C.
Precipitation amounts to only
0 mm, so on average it never rains in the whole month.
The day lasts on average 13 hours and 30 minutes.
The average humidity is 51%.
The average wind speed is of
16.3 kph.
The average sea temperature is of
14 °C. Therefore, the sea is very cold for swimming.
September is generally a warm month. However, there are remarkable differences between night and day. The average temperature is of
22 °C, with a minimum of
14.3 °C and a maximum of
29.6 °C.
On the coldest nights of the month, the temperature usually drops to around
10.5 °C.
On the warmest days of the month, the temperature usually reaches around
37 °C.
Precipitation amounts to only
0 mm, so on average it never rains in the whole month.
The day lasts on average 12 hours and 25 minutes.
The average humidity is 52%.
The average wind speed is of
13 kph.
The average sea temperature is of
14.4 °C. Therefore, the sea is very cold for swimming.
October is generally a warm month. However, there are remarkable differences between night and day. The average temperature is of
18.5 °C, with a minimum of
11.4 °C and a maximum of
25.6 °C.
On the coldest nights of the month, the temperature usually drops to around
6.5 °C.
On the warmest days of the month, the temperature usually reaches around
33 °C.
Precipitation amounts to
20 mm, distributed over 3 days.
The day lasts on average 11 hours and 10 minutes.
The average humidity is 54%.
The average wind speed is of
10.7 kph.
The average sea temperature is of
14.2 °C. Therefore, the sea is very cold for swimming.
November is generally a mild month. The average temperature is of
13.1 °C, with a minimum of
7.3 °C and a maximum of
18.9 °C.
On the coldest nights of the month, the temperature usually drops to around
2 °C.
On the warmest days of the month, the temperature usually reaches around
25.5 °C.
Precipitation amounts to
40 mm, distributed over 6 days.
The day lasts on average 10 hours and 5 minutes.
The average humidity is 67%.
The average wind speed is of
8.6 kph.
The average sea temperature is of
13.6 °C. Therefore, the sea is very cold for swimming.
December is generally a mild month. The average temperature is of
9.7 °C, with a minimum of
4.8 °C and a maximum of
14.6 °C.
On the coldest nights of the month, the temperature usually drops to around
-1 °C.
On the warmest days of the month, the temperature usually reaches around
19 °C.
Precipitation amounts to
80 mm, distributed over 10 days.
The day lasts on average 9 hours and 35 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is of
9.4 kph.
The average sea temperature is of
12.7 °C. Therefore, the sea is very cold for swimming.