Viana do Castelo weather in August
In August, Viana do Castelo sees average daytime highs of 24°C and overnight lows near 16°C, with 45 mm of rain across 5 wet days and about 13.7 hours of daylight. It is the 1st-warmest and 11th-wettest month of the year here.
Day-to-day highs hold fairly steady near 24°C through the month. The sky is clear or mostly clear about 63% of the time in August, and the air most often feels comfortable.
Daylight stretches from about 14 h 18 min at the start of August to 13 hours by month's end. Set against the rest of the year, August is Viana do Castelo's 2nd-clearest and 11th-windiest month. For the whole year in context, see Viana do Castelo's year-round climate.
- Daytime high
- 24°
- 1st warmest
- Overnight low
- 16°
- 12th coldest
- Rainfall
- 45 mm
- 5 wet days
- Daylight
- 13 h 42 min
- 5:49 AM – 7:30 PM
- Cloud cover
- 33%
- 2nd clearest
- Wind
- 12 km/h
- 11th windiest
- Solar energy
- 6.39 kWh/m²
- Travel score
- 8.3
- out of 10
Viana do Castelo is city seat of Viana do Castelo municipality in northern Portugal and seat of the municipality and district of the same name.
- Air quality
- Excellent
- PM10 9.1 µg/m³ · 2013
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in August
Day-to-day highs hold fairly steady near 24°C through the month.
A typical August day in Viana do Castelo reaches about 24°C in the afternoon and slips back to 16°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 28°C. Set against its neighbours, August runs on par with July and about 2°C warmer than September.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 |
| Avg low (°C) | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| 1 | 24 | 16 |
| 2 | 24 | 16 |
| 3 | 24 | 16 |
| 4 | 24 | 16 |
| 5 | 24 | 16 |
| 6 | 24 | 16 |
| 7 | 24 | 16 |
| 8 | 24 | 16 |
| 9 | 24 | 16 |
| 10 | 24 | 16 |
| 11 | 24 | 16 |
| 12 | 24 | 16 |
| 13 | 24 | 16 |
| 14 | 24 | 16 |
| 15 | 24 | 16 |
| 16 | 24 | 16 |
| 17 | 24 | 16 |
| 18 | 23 | 16 |
| 19 | 23 | 16 |
| 20 | 23 | 16 |
| 21 | 23 | 16 |
| 22 | 23 | 16 |
| 23 | 23 | 16 |
| 24 | 23 | 16 |
| 25 | 23 | 16 |
| 26 | 23 | 16 |
| 27 | 23 | 16 |
| 28 | 23 | 16 |
| 29 | 23 | 16 |
| 30 | 23 | 16 |
| 31 | 23 | 16 |
Viana do Castelo weather by month
How August compares with the rest of the year at a glance. August is the 1st-warmest and 11th-wettest month here — the current month is highlighted below.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 13° / 7° | 218 | 13.6 | 9.3 | 3.3 |
| Feb | 14° / 7° | 142 | 10.4 | 10.3 | 3.9 |
| Mar | 15° / 8° | 165 | 11.3 | 11.7 | 4.7 |
| Apr | 17° / 10° | 154 | 13 | 13.1 | 5.0 |
| May | 19° / 12° | 133 | 11.8 | 14.3 | 5.9 |
| Jun | 21° / 14° | 56 | 6.9 | 15 | 7.2 |
| Jul | 23° / 16° | 32 | 4.4 | 14.7 | 8.4 |
| Aug | 24° / 16° | 45 | 5 | 13.7 | 8.3 |
| Sep | 22° / 15° | 89 | 7.4 | 12.3 | 7.3 |
| Oct | 19° / 13° | 232 | 13.2 | 10.9 | 5.7 |
| Nov | 15° / 10° | 232 | 14.2 | 9.6 | 4.3 |
| Dec | 13° / 8° | 227 | 14.1 | 9 | 3.5 |
Cloud cover in August
The sky is clear or mostly clear about 63% of the time in August.
Beyond those clear spells, partly cloudy skies cover about 14% of August, with mostly cloudy or overcast conditions the remaining 22%. Skies tend to cloud over as the month goes on.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 81 | 80 | 80 | 80 | 80 | 79 | 79 | 79 | 79 | 79 | 79 | 79 | 79 | 79 | 78 | 77 | 77 | 77 | 77 | 77 | 77 | 77 | 76 | 76 | 76 | 76 | 76 | 76 | 75 | 75 | 75 |
| Cloudier (%) | 19 | 20 | 20 | 20 | 20 | 21 | 21 | 21 | 21 | 21 | 21 | 21 | 21 | 21 | 22 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 24 | 24 | 24 | 24 | 24 | 24 | 25 | 25 | 25 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 81 | 19 |
| 2 | 80 | 20 |
| 3 | 80 | 20 |
| 4 | 80 | 20 |
| 5 | 80 | 20 |
| 6 | 79 | 21 |
| 7 | 79 | 21 |
| 8 | 79 | 21 |
| 9 | 79 | 21 |
| 10 | 79 | 21 |
| 11 | 79 | 21 |
| 12 | 79 | 21 |
| 13 | 79 | 21 |
| 14 | 79 | 21 |
| 15 | 78 | 22 |
| 16 | 77 | 23 |
| 17 | 77 | 23 |
| 18 | 77 | 23 |
| 19 | 77 | 23 |
| 20 | 77 | 23 |
| 21 | 77 | 23 |
| 22 | 77 | 23 |
| 23 | 76 | 24 |
| 24 | 76 | 24 |
| 25 | 76 | 24 |
| 26 | 76 | 24 |
| 27 | 76 | 24 |
| 28 | 76 | 24 |
| 29 | 75 | 25 |
| 30 | 75 | 25 |
| 31 | 75 | 25 |
Chance of precipitation in August
Viana do Castelo gets around 45 mm of rain over 5 wet days in August. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 16% and peaks near 18% on the wettest days.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 14 | 14 | 14 | 14 | 14 | 14 | 14 | 14 | 15 | 15 | 15 | 16 | 16 | 16 | 16 | 17 | 17 | 17 | 17 | 18 | 18 | 18 | 18 | 18 | 18 | 18 | 18 | 18 | 18 | 18 | 18 |
| Rain chance (%) | |
|---|---|
| 1 | 14 |
| 2 | 14 |
| 3 | 14 |
| 4 | 14 |
| 5 | 14 |
| 6 | 14 |
| 7 | 14 |
| 8 | 14 |
| 9 | 15 |
| 10 | 15 |
| 11 | 15 |
| 12 | 16 |
| 13 | 16 |
| 14 | 16 |
| 15 | 16 |
| 16 | 17 |
| 17 | 17 |
| 18 | 17 |
| 19 | 17 |
| 20 | 18 |
| 21 | 18 |
| 22 | 18 |
| 23 | 18 |
| 24 | 18 |
| 25 | 18 |
| 26 | 18 |
| 27 | 18 |
| 28 | 18 |
| 29 | 18 |
| 30 | 18 |
| 31 | 18 |
Humidity in August
Most of August feels comfortable — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, August lands in the comfortable band about 43% of days. It rarely turns muggy — the humid and sticky bands barely register.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 8 | 9 | 9 | 10 | 11 | 11 | 11 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 11 | 11 | 12 | 12 | 12 | 13 | 13 | 13 | 14 | 14 | 15 | 15 | 16 | 16 |
| Comfortable (%) | 44 | 44 | 44 | 44 | 44 | 44 | 44 | 43 | 43 | 43 | 43 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 43 | 43 | 43 | 44 | 44 | 44 |
| Humid (%) | 45 | 44 | 44 | 43 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 43 | 43 | 43 | 44 | 44 | 44 | 44 | 44 | 44 | 44 | 44 | 43 | 43 | 42 | 41 | 41 | 40 | 40 | 39 | 39 |
| Muggy (%) | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 1 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | |
|---|---|---|---|---|
| 1 | 8 | 44 | 45 | 3 |
| 2 | 9 | 44 | 44 | 3 |
| 3 | 9 | 44 | 44 | 3 |
| 4 | 10 | 44 | 43 | 3 |
| 5 | 11 | 44 | 42 | 3 |
| 6 | 11 | 44 | 42 | 3 |
| 7 | 11 | 44 | 42 | 3 |
| 8 | 12 | 43 | 42 | 3 |
| 9 | 12 | 43 | 42 | 3 |
| 10 | 12 | 43 | 42 | 3 |
| 11 | 12 | 43 | 42 | 3 |
| 12 | 12 | 42 | 43 | 3 |
| 13 | 12 | 42 | 43 | 3 |
| 14 | 12 | 42 | 43 | 2 |
| 15 | 12 | 42 | 44 | 2 |
| 16 | 12 | 42 | 44 | 2 |
| 17 | 12 | 42 | 44 | 2 |
| 18 | 11 | 42 | 44 | 2 |
| 19 | 11 | 42 | 44 | 2 |
| 20 | 12 | 42 | 44 | 2 |
| 21 | 12 | 42 | 44 | 2 |
| 22 | 12 | 42 | 44 | 2 |
| 23 | 13 | 42 | 43 | 2 |
| 24 | 13 | 42 | 43 | 2 |
| 25 | 13 | 42 | 42 | 2 |
| 26 | 14 | 43 | 41 | 2 |
| 27 | 14 | 43 | 41 | 2 |
| 28 | 15 | 43 | 40 | 2 |
| 29 | 15 | 44 | 40 | 2 |
| 30 | 16 | 44 | 39 | 2 |
| 31 | 16 | 44 | 39 | 1 |
Wind in August
Winds average 12 km/h in August.
Across August, daily wind ranges from about 11 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 13 | 13 | 13 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 11 | 11 | 11 | 11 | 11 | 11 |
| Feels | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| 1 | 13 | light breeze |
| 2 | 13 | light breeze |
| 3 | 13 | light breeze |
| 4 | 12 | light breeze |
| 5 | 12 | light breeze |
| 6 | 12 | light breeze |
| 7 | 12 | light breeze |
| 8 | 12 | light breeze |
| 9 | 12 | light breeze |
| 10 | 12 | light breeze |
| 11 | 12 | light breeze |
| 12 | 12 | light breeze |
| 13 | 12 | light breeze |
| 14 | 12 | light breeze |
| 15 | 12 | calm |
| 16 | 12 | calm |
| 17 | 12 | calm |
| 18 | 12 | calm |
| 19 | 12 | calm |
| 20 | 12 | calm |
| 21 | 12 | calm |
| 22 | 12 | calm |
| 23 | 12 | calm |
| 24 | 12 | calm |
| 25 | 12 | calm |
| 26 | 11 | calm |
| 27 | 11 | calm |
| 28 | 11 | calm |
| 29 | 11 | calm |
| 30 | 11 | calm |
| 31 | 11 | calm |
Sunrise & sunset in August
Daylight runs from about 14 h 18 min at the start of August to 13 hours by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 78 minutes over August. Sunrise moves from 5:33 AM to 6:05 AM, and sunset from 7:50 PM to 7:06 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 14.3 | 14.2 | 14.2 | 14.2 | 14.1 | 14.1 | 14.1 | 14.0 | 14.0 | 13.9 | 13.9 | 13.9 | 13.8 | 13.8 | 13.7 | 13.7 | 13.7 | 13.6 | 13.6 | 13.5 | 13.5 | 13.4 | 13.4 | 13.3 | 13.3 | 13.3 | 13.2 | 13.2 | 13.1 | 13.1 | 13.0 |
| Sunrise (AM) | 5:33 | 5:34 | 5:35 | 5:36 | 5:37 | 5:38 | 5:39 | 5:40 | 5:41 | 5:42 | 5:43 | 5:44 | 5:45 | 5:47 | 5:48 | 5:49 | 5:50 | 5:51 | 5:52 | 5:53 | 5:54 | 5:55 | 5:56 | 5:57 | 5:58 | 5:59 | 6:00 | 6:01 | 6:02 | 6:03 | 6:05 |
| Sunset (PM) | 7:50 | 7:48 | 7:47 | 7:46 | 7:45 | 7:44 | 7:43 | 7:41 | 7:40 | 7:39 | 7:37 | 7:36 | 7:35 | 7:33 | 7:32 | 7:30 | 7:29 | 7:27 | 7:26 | 7:24 | 7:23 | 7:21 | 7:19 | 7:18 | 7:16 | 7:15 | 7:13 | 7:11 | 7:10 | 7:08 | 7:06 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 14.3 | 5:33 | 7:50 |
| 2 | 14.2 | 5:34 | 7:48 |
| 3 | 14.2 | 5:35 | 7:47 |
| 4 | 14.2 | 5:36 | 7:46 |
| 5 | 14.1 | 5:37 | 7:45 |
| 6 | 14.1 | 5:38 | 7:44 |
| 7 | 14.1 | 5:39 | 7:43 |
| 8 | 14.0 | 5:40 | 7:41 |
| 9 | 14.0 | 5:41 | 7:40 |
| 10 | 13.9 | 5:42 | 7:39 |
| 11 | 13.9 | 5:43 | 7:37 |
| 12 | 13.9 | 5:44 | 7:36 |
| 13 | 13.8 | 5:45 | 7:35 |
| 14 | 13.8 | 5:47 | 7:33 |
| 15 | 13.7 | 5:48 | 7:32 |
| 16 | 13.7 | 5:49 | 7:30 |
| 17 | 13.7 | 5:50 | 7:29 |
| 18 | 13.6 | 5:51 | 7:27 |
| 19 | 13.6 | 5:52 | 7:26 |
| 20 | 13.5 | 5:53 | 7:24 |
| 21 | 13.5 | 5:54 | 7:23 |
| 22 | 13.4 | 5:55 | 7:21 |
| 23 | 13.4 | 5:56 | 7:19 |
| 24 | 13.3 | 5:57 | 7:18 |
| 25 | 13.3 | 5:58 | 7:16 |
| 26 | 13.3 | 5:59 | 7:15 |
| 27 | 13.2 | 6:00 | 7:13 |
| 28 | 13.2 | 6:01 | 7:11 |
| 29 | 13.1 | 6:02 | 7:10 |
| 30 | 13.1 | 6:03 | 7:08 |
| 31 | 13.0 | 6:05 | 7:06 |
Solar energy in August
Average shortwave solar energy reaching the ground each day in August, about 6.39 kWh/m².
For context, solar energy here swings from a low near 1.59 kWh/m² to a high of 7.29 kWh/m² in July across the year — August's 6.39 kWh/m² falls in the middle.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 7.0 | 7.0 | 6.9 | 6.9 | 6.8 | 6.8 | 6.8 | 6.7 | 6.7 | 6.7 | 6.6 | 6.6 | 6.5 | 6.5 | 6.4 | 6.4 | 6.3 | 6.3 | 6.3 | 6.2 | 6.2 | 6.1 | 6.1 | 6.0 | 6.0 | 6.0 | 5.9 | 5.9 | 5.8 | 5.8 | 5.8 |
| Level | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 7.0 | Intense |
| 2 | 7.0 | Intense |
| 3 | 6.9 | Intense |
| 4 | 6.9 | Intense |
| 5 | 6.8 | Intense |
| 6 | 6.8 | Intense |
| 7 | 6.8 | Intense |
| 8 | 6.7 | Intense |
| 9 | 6.7 | Intense |
| 10 | 6.7 | Intense |
| 11 | 6.6 | Intense |
| 12 | 6.6 | Intense |
| 13 | 6.5 | Intense |
| 14 | 6.5 | Intense |
| 15 | 6.4 | Intense |
| 16 | 6.4 | Intense |
| 17 | 6.3 | Intense |
| 18 | 6.3 | Intense |
| 19 | 6.3 | Intense |
| 20 | 6.2 | Intense |
| 21 | 6.2 | Intense |
| 22 | 6.1 | Intense |
| 23 | 6.1 | Intense |
| 24 | 6.0 | Intense |
| 25 | 6.0 | Intense |
| 26 | 6.0 | Bright |
| 27 | 5.9 | Bright |
| 28 | 5.9 | Bright |
| 29 | 5.8 | Bright |
| 30 | 5.8 | Bright |
| 31 | 5.8 | Bright |
Hazard calendar for Viana do Castelo
None of Viana do Castelo's seasonal hazards are active in August. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.
Viana do Castelo's rainy season runs October–May, when most of the year's rain falls.
Is August a good time to visit Viana do Castelo?
Our two travel scores rate August for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
August is one of the better times to visit Viana do Castelo for general sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Viana do Castelo in August
From August's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In August, Viana do Castelo sees daytime highs around 24°C and nights near 16°C. Pack sun protection. Worth having: light clothes. About 5 days see rain.
Sea temperature near Viana do Castelo in August
The nearest coast averages about 17°C in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea offshore is warmest in August at about 17°C and coldest in February near 13°C.
The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 14 | 13 | 14 | 14 | 15 | 17 | 17 | 17 | 17 | 17 | 16 | 15 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Cool | Cool | Cool | Cool | Cool | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 14 | Bracing |
| Feb | 13 | Bracing |
| Mar | 14 | Bracing |
| Apr | 14 | Bracing |
| May | 15 | Cool |
| Jun | 17 | Cool |
| Jul | 17 | Cool |
| Aug | 17 | Cool |
| Sep | 17 | Cool |
| Oct | 17 | Cool |
| Nov | 16 | Cool |
| Dec | 15 | Bracing |
UV index in Viana do Castelo in August
Clear-sky midday UV in August peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Viana do Castelo peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 2 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 3 | 5 | 6 | 7 | 9 | 9 | 8 | 6 | 4 | 2 | 2 |
| Level | Low | Moderate | Moderate | High | High | Very high | Very high | Very high | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 3 | Moderate |
| Mar | 5 | Moderate |
| Apr | 6 | High |
| May | 7 | High |
| Jun | 9 | Very high |
| Jul | 9 | Very high |
| Aug | 8 | Very high |
| Sep | 6 | High |
| Oct | 4 | Moderate |
| Nov | 2 | Moderate |
| Dec | 2 | Low |
Where is Viana do Castelo?
Viana do Castelo sits at 41.7°N, 8.8°W, 12 m above sea level, in Portugal. The nearest listed city is Esposende, 18 km away.
Topography around Viana do Castelo
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Viana do Castelo.
Within 3 km, the terrain around Viana do Castelo has significant variations in elevation — a maximum elevation change of 300 m around an average of 29 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 793 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,517 m.
The land around Viana do Castelo is covered by water (37%), trees (23%) and artificial surfaces (22%) within 3 km, water (47%) and trees (29%) within 16 km, and trees (38%), water (32%) and grassland (22%) within 80 km.
Portugal travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type C / E / F
- 230 V · 50 Hz
- Prices
- ≈ 60% of US
- price level, 2025
- GDP per capita
- $32,082
- 2025
- Happiness
- 6.0 / 10
- World Happiness, 2025
- Safe drinking water
- 95%
- of population, 2024
- Homicide rate
- 0.7
- per 100k, 2022
- Road deaths
- 8.2
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Very high
- EF EPI 612
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Viana do Castelo (41.6932°, -8.8329°, elevation 12 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).