Monthly climate in Acton, California, United States

Last updated: March 2, 2024

Under the Köppen–Geiger climate classification Acton features a warm-summer Mediterranean climate (Csb). Temperatures typically range between 9 °C (49 °F) and 25 °C (78 °F) through the year, but rarely can drop to -2 °C (28 °F) or can rise to as high as 42 °C (107 °F). The average annual precipitation amounts to about 331 mm (13.0 inches) and receives 37 rainy days on the 1 mm (0.04 inches) threshold annually. Acton enjoys an average of 3558 hours of sunshine throughout the year, and daylight varies from 9 hours 52 minutes to 14 hours 24 minutes per day.

Monthly average temperatures in Acton, California, United States §

The warmest months in Acton are July, August and September, with daily mean temperatures ranging from 23 to 25 °C (73 - 78 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 9 to 10 °C (49 - 50 °F) throughout the day. On average each year, Acton experiences 132 days above 25 °C (77.0 °F) and 6 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Acton, California, United States. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 24°C
(76°F)
25°C
(77°F)
28°C
(82°F)
31°C
(89°F)
33°C
(92°F)
41°C
(105°F)
40°C
(103°F)
39°C
(103°F)
42°C
(107°F)
36°C
(97°F)
28°C
(83°F)
24°C
(75°F)
Mean maximum 21°C
(70°F)
22°C
(72°F)
25°C
(78°F)
30°C
(86°F)
31°C
(88°F)
35°C
(95°F)
38°C
(100°F)
38°C
(100°F)
37°C
(99°F)
31°C
(88°F)
27°C
(81°F)
22°C
(71°F)
Average high 15°C
(59°F)
16°C
(60°F)
17°C
(63°F)
22°C
(71°F)
24°C
(75°F)
29°C
(84°F)
32°C
(90°F)
32°C
(90°F)
30°C
(86°F)
25°C
(77°F)
20°C
(69°F)
15°C
(59°F)
Daily mean 9°C
(49°F)
10°C
(50°F)
11°C
(53°F)
15°C
(60°F)
17°C
(64°F)
22°C
(72°F)
25°C
(78°F)
25°C
(78°F)
23°C
(73°F)
18°C
(65°F)
14°C
(57°F)
9°C
(49°F)
Average low 5°C
(42°F)
5°C
(42°F)
6°C
(44°F)
10°C
(50°F)
12°C
(53°F)
16°C
(61°F)
19°C
(67°F)
19°C
(67°F)
17°C
(63°F)
12°C
(55°F)
9°C
(48°F)
5°C
(41°F)
Mean minimum -0°C
(32°F)
-1°C
(31°F)
0°C
(33°F)
4°C
(40°F)
6°C
(43°F)
10°C
(51°F)
15°C
(59°F)
15°C
(59°F)
11°C
(53°F)
7°C
(45°F)
3°C
(39°F)
-0°C
(32°F)
Minimum -2°C
(28°F)
-2°C
(28°F)
-1°C
(30°F)
4°C
(39°F)
4°C
(40°F)
9°C
(49°F)
12°C
(54°F)
14°C
(58°F)
9°C
(48°F)
4°C
(39°F)
-0°C
(31°F)
-2°C
(29°F)

Compare climate in Acton with other places

Compare temperature, precipitation, sunshine, UV index in Acton, California, United States with other places around the world.

Monthly average precipitation in Acton, California, United States §

Acton usually has the most precipitation in January, March and December, with an average of 7 rainy days and 66 mm (2.6 inches) of precipitation per month. The driest months in Acton are June, July and August. On average, 4 mm (0.2 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Acton, California, United States. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 58 (2.3) 53 (2.1) 73 (2.9) 22 (0.9) 13 (0.5) 3 (0.1) 4 (0.2) 6 (0.2) 6 (0.3) 7 (0.3) 20 (0.8) 65 (2.6)
Average precipitation days (≥ 1 mm) 5 6 10 2 2 0 1 1 1 1 2 6

Monthly sunshine hours in Acton, California, United States §

The sunniest months in Acton are June, July and August, when the sun shines an average of 12 hours 4 minutes a day. Least sunny months in Acton: January, February and December receive an average of 6 hours 58 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Acton, California, United States. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 185 227 276 316 355 369 381 361 315 292 255 222
Mean daily daylight hours 10h 7m 10h 56m 11h 59m 13h 4m 13h 58m 14h 24m 14h 10m 13h 22m 12h 20m 11h 16m 10h 20m 9h 52m

Solar UV radiation in Acton, California, United States §

Acton experiences the highest level of ultraviolet (UV) radiation in May, July and August, when the maximum UV index can reach values of 11 - 12, which corresponds to the Extreme category of sun exposure. January, November and December are in the Moderate exposure category. In these months, the maximum values of the UV index do not exceed 5. For more detailed information, check out our hourly Acton UV Index data.

Average daily maximum UV levels by month for Acton, California, United States. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 4 6 8 10 11 11 12 11 10 7 5 4

Detailed Monthly Weather Insights for Acton, California, United States

Discover in-depth weather details for every month in Acton. Click through the links below for comprehensive overviews of temperature trends, precipitation levels, sunshine hours, and solar UV radiation specifics. Whether planning a visit or simply curious about Acton's climate nuances, these monthly breakdowns provide the information you need for an informed understanding of what to expect throughout the year.

Each link leads to a detailed account of the typical weather conditions for that month, providing both locals and tourists with vital information to plan their daily activities, wardrobe, and travel itineraries accordingly.