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Monthly climate in Viana do Castelo, Portugal

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Viana do Castelo features a warm-summer Mediterranean climate (Csb). Temperatures typically range between 9 °C (49 °F) and 20 °C (67 °F) through the year, but rarely can drop to -1 °C (31 °F) or can rise to as high as 32 °C (90 °F). The average annual precipitation amounts to about 1561 mm (61.4 inches) and receives 122 rainy days on the 1 mm (0.04 inches) threshold annually. Viana do Castelo enjoys an average of 3666 hours of sunshine throughout the year, and daylight varies from 9 hours 11 minutes to 15 hours 8 minutes per day.

Monthly average temperatures in Viana do Castelo, Portugal

The warmest months in Viana do Castelo are July, August and September, with daily mean temperatures ranging from 19 to 20 °C (66 - 67 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 9 to 11 °C (49 - 52 °F) throughout the day. On average each year, Viana do Castelo experiences 23 days above 25 °C (77.0 °F) and 0 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Viana do Castelo. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum20°C
(69°F)		21°C
(70°F)		23°C
(73°F)		26°C
(79°F)		29°C
(84°F)		28°C
(84°F)		30°C
(87°F)		32°C
(90°F)		30°C
(86°F)		29°C
(84°F)		21°C
(70°F)		19°C
(66°F)
Mean maximum17°C
(62°F)		19°C
(67°F)		20°C
(69°F)		23°C
(74°F)		26°C
(79°F)		26°C
(79°F)		29°C
(84°F)		29°C
(84°F)		28°C
(83°F)		24°C
(76°F)		20°C
(68°F)		18°C
(64°F)
Average high13°C
(56°F)		15°C
(58°F)		15°C
(60°F)		17°C
(63°F)		19°C
(67°F)		20°C
(69°F)		23°C
(74°F)		23°C
(74°F)		23°C
(73°F)		20°C
(68°F)		16°C
(60°F)		14°C
(57°F)
Daily mean9°C
(49°F)		11°C
(52°F)		12°C
(53°F)		13°C
(56°F)		16°C
(61°F)		17°C
(63°F)		20°C
(67°F)		20°C
(67°F)		19°C
(66°F)		16°C
(61°F)		12°C
(54°F)		11°C
(52°F)
Average low6°C
(43°F)		8°C
(46°F)		8°C
(47°F)		10°C
(50°F)		12°C
(54°F)		14°C
(57°F)		16°C
(61°F)		16°C
(61°F)		15°C
(59°F)		12°C
(55°F)		9°C
(49°F)		8°C
(47°F)
Mean minimum1°C
(34°F)		3°C
(37°F)		4°C
(39°F)		5°C
(41°F)		8°C
(46°F)		11°C
(52°F)		12°C
(55°F)		12°C
(54°F)		11°C
(52°F)		7°C
(45°F)		5°C
(41°F)		3°C
(38°F)
Minimum-1°C
(31°F)		1°C
(35°F)		2°C
(37°F)		3°C
(38°F)		6°C
(43°F)		9°C
(48°F)		11°C
(53°F)		12°C
(54°F)		10°C
(50°F)		6°C
(43°F)		3°C
(38°F)		2°C
(36°F)

Compare climate in Viana do Castelo with other places

Compare temperature, precipitation, sunshine, UV index in Viana do Castelo, Portugal with other places around the world.

Monthly average precipitation in Viana do Castelo, Portugal

Viana do Castelo usually has the most precipitation in March, November and December, with an average of 15 rainy days and 216 mm (8.5 inches) of precipitation per month. The driest months in Viana do Castelo are July, August and September. On average, 35 mm (1.4 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Viana do Castelo. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)136 (5.4)185 (7.3)186 (7.3)169 (6.7)106 (4.2)59 (2.3)26 (1.0)30 (1.2)49 (1.9)152 (6.0)216 (8.5)246 (9.7)
Average precipitation days (≥ 1 mm)1013131397536111517

Monthly sunshine hours in Viana do Castelo, Portugal

The sunniest months in Viana do Castelo are May, June and July, when the sun shines an average of 13 hours 27 minutes a day. Least sunny months in Viana do Castelo: January, November and December receive an average of 5 hours 54 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Viana do Castelo. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours155207288347404406427394346301206180
Mean daily daylight hours9h 31m10h 35m11h 57m13h 21m14h 32m15h 8m14h 49m13h 46m12h 25m11h 2m9h 49m9h 11m

Solar UV radiation in Viana do Castelo, Portugal

Viana do Castelo experiences the highest level of ultraviolet (UV) radiation in May, June and August, when the maximum UV index can reach values of 9 - 10, which corresponds to the Very High category of sun exposure. January, November and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 3. For more detailed information, check out our hourly Viana do Castelo UV Index data.

Average daily maximum UV levels by month for Viana do Castelo. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)2468910997632