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Monthly climate in Williamstown, Australia

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Williamstown features a warm-summer Mediterranean climate (Csb). Temperatures typically range between 9 °C (48 °F) and 21 °C (70 °F) through the year, but rarely can drop to -2 °C (29 °F) or can rise to as high as 43 °C (110 °F). The average annual precipitation amounts to about 402 mm (15.8 inches) and receives 75 rainy days on the 1 mm (0.04 inches) threshold annually. Williamstown enjoys an average of 3332 hours of sunshine throughout the year, and daylight varies from 9 hours 50 minutes to 14 hours 26 minutes per day.

Monthly average temperatures in Williamstown, Australia

The warmest months in Williamstown are January, February and December, with daily mean temperatures ranging from 19 to 21 °C (66 - 70 °F) throughout the day. The coldest temperatures usually occur in June, July and August, when daily mean temperatures range from 9 to 9 °C (48 - 49 °F) throughout the day. On average each year, Williamstown experiences 80 days above 25 °C (77.0 °F) and 2 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Williamstown. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum43°C
(110°F)		38°C
(100°F)		38°C
(100°F)		35°C
(95°F)		26°C
(79°F)		20°C
(69°F)		21°C
(70°F)		22°C
(72°F)		28°C
(83°F)		35°C
(94°F)		41°C
(105°F)		42°C
(108°F)
Mean maximum40°C
(104°F)		36°C
(97°F)		33°C
(92°F)		30°C
(87°F)		23°C
(73°F)		17°C
(63°F)		19°C
(66°F)		21°C
(70°F)		26°C
(80°F)		30°C
(86°F)		35°C
(96°F)		37°C
(99°F)
Average high28°C
(83°F)		26°C
(79°F)		25°C
(77°F)		21°C
(71°F)		16°C
(61°F)		13°C
(57°F)		13°C
(56°F)		13°C
(56°F)		17°C
(62°F)		20°C
(68°F)		23°C
(73°F)		26°C
(79°F)
Daily mean21°C
(70°F)		19°C
(67°F)		18°C
(65°F)		16°C
(60°F)		11°C
(53°F)		9°C
(48°F)		9°C
(48°F)		9°C
(49°F)		11°C
(53°F)		14°C
(57°F)		17°C
(62°F)		19°C
(66°F)
Average low14°C
(58°F)		14°C
(57°F)		13°C
(55°F)		10°C
(51°F)		7°C
(46°F)		5°C
(42°F)		5°C
(42°F)		5°C
(41°F)		6°C
(43°F)		8°C
(47°F)		10°C
(51°F)		12°C
(54°F)
Mean minimum9°C
(49°F)		8°C
(47°F)		7°C
(45°F)		5°C
(41°F)		3°C
(37°F)		1°C
(34°F)		0°C
(33°F)		-1°C
(31°F)		1°C
(34°F)		3°C
(38°F)		4°C
(39°F)		7°C
(44°F)
Minimum8°C
(46°F)		7°C
(45°F)		6°C
(43°F)		3°C
(38°F)		2°C
(36°F)		-2°C
(29°F)		-1°C
(30°F)		-2°C
(29°F)		-0°C
(32°F)		3°C
(37°F)		3°C
(38°F)		6°C
(43°F)

Compare climate in Williamstown with other places

Compare temperature, precipitation, sunshine, UV index in Williamstown, Australia with other places around the world.

Monthly average precipitation in Williamstown, Australia

Williamstown usually has the most precipitation in July, August and November, with an average of 9 rainy days and 52 mm (2.1 inches) of precipitation per month. The driest months in Williamstown are January, March and December. On average, 14 mm (0.5 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Williamstown. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)16 (0.6)21 (0.8)10 (0.4)25 (1.0)40 (1.6)42 (1.7)50 (2.0)65 (2.6)38 (1.5)37 (1.5)43 (1.7)16 (0.6)
Average precipitation days (≥ 1 mm)22349811118674

Monthly sunshine hours in Williamstown, Australia

The sunniest months in Williamstown are March, November and December, when the sun shines an average of 10 hours 33 minutes a day. Least sunny months in Williamstown: May, June and July receive an average of 7 hours 30 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Williamstown. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours293296306256233220236247275300312352
Mean daily daylight hours14h 10m13h 20m12h 16m11h 10m10h 17m9h 50m10h 3m10h 50m11h 52m12h 57m13h 55m14h 26m

Solar UV radiation in Williamstown, Australia

Williamstown experiences the highest level of ultraviolet (UV) radiation in January, November and December, when the maximum UV index can reach values of 13 - 15, which corresponds to the Extreme category of sun exposure. May, June and July 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 Williamstown UV Index data.

Average daily maximum UV levels by month for Williamstown. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)141312853458101315