Climate and average weather in Viseu
In Viseu, the summers are warm, fairly dry, and clear and the winters are cool and partly cloudy.
Over the course of the year, the temperature in Viseu typically varies from 4°C to 27°C, and is rarely below -1°C or above 33°C. August is the hottest month of the year, while January is the coldest.
Based on the travel score, the best time of year to visit Viseu for warm-weather activities is from late May to early October.
- Hottest
- Aug
- 27°
- Coldest
- Jan
- 4°
- Wettest
- Oct
- 168 mm
- Driest
- Jul
- 19 mm
- Rain / yr
- 1214 mm
- 114 wet days
- Daylight
- 9.1–14.9 h
- shortest–longest
- Elevation
- 469 m
- 40.7°N
- Clearest
- Jul
- 26% cloud
Viseu is city seat of Viseu municipality.
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Viseu weather by month, at a glance
The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.
Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around late May to early October.
Temperature through the year
Daily average highs and lows in Viseu, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 3.2 months, from June 13 to September 18, with daily high temperatures above 23°C. The hottest month of the year in Viseu is August, with an average high of 27°C and low of 15°C.
The cool season lasts 3.6 months, from November 15 to March 4, with daily high temperatures below 14°C. The coldest month of the year in Viseu is January, with an average low of 4°C and high of 11°C.
Days typically run about 9°C warmer than nights, with the widest day–night swing (around 12°C) in July.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 11 | 12 | 15 | 17 | 20 | 23 | 27 | 27 | 24 | 19 | 14 | 11 |
| Avg low (°C) | 4 | 4 | 6 | 7 | 10 | 13 | 15 | 15 | 13 | 10 | 7 | 5 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 11 | 4 |
| Feb | 12 | 4 |
| Mar | 15 | 6 |
| Apr | 17 | 7 |
| May | 20 | 10 |
| Jun | 23 | 13 |
| Jul | 27 | 15 |
| Aug | 27 | 15 |
| Sep | 24 | 13 |
| Oct | 19 | 10 |
| Nov | 14 | 7 |
| Dec | 11 | 5 |
Average hourly temperature in Viseu
A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on August afternoons, near 27°C, and coldest before dawn in January, near 4°C.
Viseu weather by month
Every month at a glance. Click a month for its detailed page.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 11° / 4° | 152 | 11.6 | 0.5 | 9.4 | 2.5 |
| Feb | 12° / 4° | 102 | 9.3 | 0.3 | 10.4 | 3.3 |
| Mar | 15° / 6° | 115 | 10.6 | 0 | 11.7 | 4.5 |
| Apr | 17° / 7° | 118 | 12.8 | 0 | 13.1 | 4.9 |
| May | 20° / 10° | 98 | 11.6 | 0 | 14.2 | 6.1 |
| Jun | 23° / 13° | 40 | 6.2 | 0 | 14.9 | 7.7 |
| Jul | 27° / 15° | 19 | 3.7 | 0 | 14.6 | 8.2 |
| Aug | 27° / 15° | 26 | 4.6 | 0 | 13.6 | 8.0 |
| Sep | 24° / 13° | 66 | 7.1 | 0 | 12.3 | 7.6 |
| Oct | 19° / 10° | 168 | 12.2 | 0 | 10.9 | 5.7 |
| Nov | 14° / 7° | 150 | 12.7 | 0.1 | 9.7 | 3.7 |
| Dec | 11° / 5° | 160 | 11.6 | 0.1 | 9.1 | 2.7 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Viseu gets about 1214 mm of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.
The wetter season lasts 5.2 months, from around Oct 5 to Mar 11, peaking in October at about 46% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jul 21.
October is the wettest month by volume, with 168 mm over about 12 wet days; July is the driest, with 19 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 38 | 33 | 34 | 42 | 37 | 22 | 12 | 14 | 24 | 40 | 41 | 38 |
| Rain days | 12 | 9 | 11 | 13 | 12 | 6 | 4 | 5 | 7 | 12 | 13 | 12 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 38 | 12 |
| Feb | 33 | 9 |
| Mar | 34 | 11 |
| Apr | 42 | 13 |
| May | 37 | 12 |
| Jun | 22 | 6 |
| Jul | 12 | 4 |
| Aug | 14 | 5 |
| Sep | 24 | 7 |
| Oct | 40 | 12 |
| Nov | 41 | 13 |
| Dec | 38 | 12 |
Monthly rainfall
Over a full year, Viseu collects about 1214 mm of rain across 114 wet days — roughly 101 mm in an average month.
It doesn’t fall evenly. October is the wettest month with 168 mm, while July is the driest at just 19 mm. The three wettest months alone bring about 40% of the year’s total, and some of the cold-season precipitation falls as snow.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 152 | 102 | 115 | 118 | 98 | 40 | 19 | 26 | 66 | 168 | 150 | 160 |
| Rain days | 12 | 9 | 11 | 13 | 12 | 6 | 4 | 5 | 7 | 12 | 13 | 12 |
| Snow days | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Rainfall (mm) | Rain days | Snow days | |
|---|---|---|---|
| Jan | 152 | 12 | 1 |
| Feb | 102 | 9 | 0 |
| Mar | 115 | 11 | 0 |
| Apr | 118 | 13 | 0 |
| May | 98 | 12 | 0 |
| Jun | 40 | 6 | 0 |
| Jul | 19 | 4 | 0 |
| Aug | 26 | 5 | 0 |
| Sep | 66 | 7 | 0 |
| Oct | 168 | 12 | 0 |
| Nov | 150 | 13 | 0 |
| Dec | 160 | 12 | 0 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Viseu, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.
The clearer part of the year begins around June 3 and lasts for 4.1 months, ending around October 6. The clearest month is July, when the sky is clear, mostly clear, or partly cloudy 82% of the time on average.
The cloudier part of the year begins around October 7 and lasts for 7.9 months, ending around June 2. The cloudiest month is November, when it is overcast or mostly cloudy 60% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 43 | 46 | 46 | 43 | 47 | 62 | 82 | 81 | 67 | 45 | 40 | 41 |
| Cloudier (%) | 57 | 54 | 54 | 57 | 53 | 38 | 18 | 19 | 33 | 55 | 60 | 59 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 43 | 57 |
| Feb | 46 | 54 |
| Mar | 46 | 54 |
| Apr | 43 | 57 |
| May | 47 | 53 |
| Jun | 62 | 38 |
| Jul | 82 | 18 |
| Aug | 81 | 19 |
| Sep | 67 | 33 |
| Oct | 45 | 55 |
| Nov | 40 | 60 |
| Dec | 41 | 59 |
Daylight, sunrise and sunset
Hours of daylight through the year, with sunrise and sunset times.
The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 12, brings about 14 h 54 min of light; the shortest, around January 1, only 9 h 06 min — a swing of roughly 5 h 48 min.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 9.4 | 10.4 | 11.7 | 13.1 | 14.2 | 14.9 | 14.6 | 13.6 | 12.3 | 10.9 | 9.7 | 9.1 |
| Sunrise (AM) | 7:59 | 7:35 | 6:51 | 5:59 | 5:20 | 5:05 | 5:18 | 5:47 | 6:18 | 6:50 | 7:26 | 7:55 |
| Sunset (PM) | 5:23 | 5:58 | 6:31 | 7:04 | 7:36 | 7:59 | 7:57 | 7:25 | 6:34 | 5:44 | 5:08 | 5:01 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 9.4 | 7:59 | 5:23 |
| Feb | 10.4 | 7:35 | 5:58 |
| Mar | 11.7 | 6:51 | 6:31 |
| Apr | 13.1 | 5:59 | 7:04 |
| May | 14.2 | 5:20 | 7:36 |
| Jun | 14.9 | 5:05 | 7:59 |
| Jul | 14.6 | 5:18 | 7:57 |
| Aug | 13.6 | 5:47 | 7:25 |
| Sep | 12.3 | 6:18 | 6:34 |
| Oct | 10.9 | 6:50 | 5:44 |
| Nov | 9.7 | 7:26 | 5:08 |
| Dec | 9.1 | 7:55 | 5:01 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Viseu averages about 12 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 7 and 23 days.
The sunnier stretch runs 4.0 months, from around Jun 7 to Oct 5. The sunniest month is July, with roughly 21 sunny days (bright).
The greyest month is May, down near 9 sunny days — about 57% fewer than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 10 | 10 | 10 | 8 | 9 | 15 | 22 | 21 | 16 | 10 | 9 | 10 |
| Sky | Mixed | Mixed | Mixed | Mixed | Mixed | Mixed | Bright | Bright | Bright | Mixed | Mixed | Mixed |
| Sunny days | Sky | |
|---|---|---|
| Jan | 10 | Mixed |
| Feb | 10 | Mixed |
| Mar | 10 | Mixed |
| Apr | 8 | Mixed |
| May | 9 | Mixed |
| Jun | 15 | Mixed |
| Jul | 22 | Bright |
| Aug | 21 | Bright |
| Sep | 16 | Bright |
| Oct | 10 | Mixed |
| Nov | 9 | Mixed |
| Dec | 10 | Mixed |
Humidity comfort
Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.
Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.
In Viseu, the air stays dry or comfortable essentially all year. Even in July, the muggiest month, it feels humid or worse only about 12% of the time — humidity is not something you need to plan around here.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 100 | 100 | 100 | 99 | 87 | 62 | 37 | 39 | 63 | 79 | 95 | 100 |
| Comfortable (%) | 0 | 0 | 0 | 1 | 12 | 33 | 50 | 49 | 33 | 19 | 5 | 0 |
| Humid (%) | 0 | 0 | 0 | 0 | 1 | 5 | 12 | 12 | 4 | 2 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | |
|---|---|---|---|
| Jan | 100 | 0 | 0 |
| Feb | 100 | 0 | 0 |
| Mar | 100 | 0 | 0 |
| Apr | 99 | 1 | 0 |
| May | 87 | 12 | 1 |
| Jun | 62 | 33 | 5 |
| Jul | 37 | 50 | 12 |
| Aug | 39 | 49 | 12 |
| Sep | 63 | 33 | 4 |
| Oct | 79 | 19 | 2 |
| Nov | 95 | 5 | 0 |
| Dec | 100 | 0 | 0 |
Wind
Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.
This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.
Wind in Viseu is steady company: average speeds sit near 9 km/h — calm — in every month of the year, with no meaningful windy or calm season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 10 | 10 | 10 | 10 | 9 | 9 | 8 | 8 | 8 | 9 | 10 | 10 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 10 | calm |
| Feb | 10 | calm |
| Mar | 10 | calm |
| Apr | 10 | calm |
| May | 9 | calm |
| Jun | 9 | calm |
| Jul | 8 | calm |
| Aug | 8 | calm |
| Sep | 8 | calm |
| Oct | 9 | calm |
| Nov | 10 | calm |
| Dec | 10 | calm |
Hazard calendar for Viseu
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
Viseu's rainy season runs October–May, when most of the year's rain falls.
Best time to visit Viseu
To characterize how pleasant the weather is in Viseu throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around late September, Viseu is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.
Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.
The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit Viseu for general outdoor tourist activities is from late May to early October, with a peak score in the third week of July.
The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Travel score (0–10) | 2.5 | 3.3 | 4.5 | 4.9 | 6.1 | 7.7 | 8.2 | 8.0 | 7.6 | 5.7 | 3.7 | 2.7 |
| Rating | poor | poor | fair | fair | good | ideal | ideal | ideal | ideal | good | fair | poor |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 2.5 | poor |
| Feb | 3.3 | poor |
| Mar | 4.5 | fair |
| Apr | 4.9 | fair |
| May | 6.1 | good |
| Jun | 7.7 | ideal |
| Jul | 8.2 | ideal |
| Aug | 8.0 | ideal |
| Sep | 7.6 | ideal |
| Oct | 5.7 | good |
| Nov | 3.7 | fair |
| Dec | 2.7 | poor |
The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Viseu for hot-weather activities is from late June to mid September, with a peak score in the last week of July.
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
What to pack for Viseu, by month
Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.
For a warm-season trip around August (highs near 27°C), the essentials are light clothes and sun protection. In the cold season around January (highs near 11°C), pack a warm layer and rain gear.
In August, Viseu sees daytime highs around 27°C and nights near 15°C. Pack sun protection. Worth having: light clothes. About 5 days see rain.
UV index (midday) in Viseu by month
Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.
Under clear skies, the midday UV index in Viseu peaks around July 13 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 | 7 | 7 | 9 | 9 | 9 | 6 | 5 | 2 | 2 |
| Level | Low | Moderate | High | High | High | Very high | Very high | Very high | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 3 | Moderate |
| Mar | 5 | High |
| Apr | 7 | High |
| May | 7 | High |
| Jun | 9 | Very high |
| Jul | 9 | Very high |
| Aug | 9 | Very high |
| Sep | 6 | High |
| Oct | 5 | Moderate |
| Nov | 2 | Moderate |
| Dec | 2 | Low |
Average hourly UV index in Viseu
Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.
The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
UV falls off far faster than brightness as the sun drops, so even in July the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 5.5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV ≥ 3 (h/day) | 0 | 0 | 5 | 6.5 | 7.5 | 8.5 | 8.5 | 7.5 | 6 | 4.5 | 0 | 0 |
| UV ≥ 6 (h/day) | 0 | 0 | 0 | 2.5 | 3.5 | 5.5 | 5.5 | 4.5 | 0 | 0 | 0 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 0 | 0 |
| Feb | 0 | 0 |
| Mar | 5 | 0 |
| Apr | 6.5 | 2.5 |
| May | 7.5 | 3.5 |
| Jun | 8.5 | 5.5 |
| Jul | 8.5 | 5.5 |
| Aug | 7.5 | 4.5 |
| Sep | 6 | 0 |
| Oct | 4.5 | 0 |
| Nov | 0 | 0 |
| Dec | 0 | 0 |
Air quality in Viseu by month
Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.
Air quality in Viseu is worst in October — around 29 µg/m³ PM2.5 (moderate), about 3.9× the cleanest month (November, 7 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 9 | 10 | 13 | 11 | 8 | 21 | 9 | 24 | 23 | 29 | 7 | 7 |
| Level | Good | Good | Moderate | Good | Good | Moderate | Good | Moderate | Moderate | Moderate | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 9 | Good |
| Feb | 10 | Good |
| Mar | 13 | Moderate |
| Apr | 11 | Good |
| May | 8 | Good |
| Jun | 21 | Moderate |
| Jul | 9 | Good |
| Aug | 24 | Moderate |
| Sep | 23 | Moderate |
| Oct | 29 | Moderate |
| Nov | 7 | Good |
| Dec | 7 | Good |
Growing season
Viseu is mild enough that a frost-free day stays more likely than not even in midwinter. Nights are reliably above freezing from about February 10 to December 17 (311 days); outside that window a hard frost is an occasional risk.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 87 | 91 | 98 | 99 | 100 | 100 | 100 | 100 | 100 | 100 | 97 | 91 |
| Frost nights | 31 | 10 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 15 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 87 | 31 |
| Feb | 91 | 10 |
| Mar | 98 | 0 |
| Apr | 99 | 0 |
| May | 100 | 0 |
| Jun | 100 | 0 |
| Jul | 100 | 0 |
| Aug | 100 | 0 |
| Sep | 100 | 0 |
| Oct | 100 | 0 |
| Nov | 97 | 0 |
| Dec | 91 | 15 |
Growing degree days
Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Viseu banks about 1,537 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 0 | 0 | 20 | 58 | 146 | 243 | 326 | 335 | 250 | 141 | 18 | 0 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 0 |
| Feb | 0 |
| Mar | 20 |
| Apr | 58 |
| May | 146 |
| Jun | 243 |
| Jul | 326 |
| Aug | 335 |
| Sep | 250 |
| Oct | 141 |
| Nov | 18 |
| Dec | 0 |
Solar energy
Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.
Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.
Viseu receives about 4.4 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 1.6 and 7.3 kWh/m².
The brighter stretch of the year lasts 6.0 months, from around Mar 24 to Sep 23. The brightest month is July, averaging about 7.2 kWh/m² (intense).
The dimmest month is December, down near 1.7 kWh/m² — roughly 77% less than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 1.9 | 2.9 | 4.1 | 5.1 | 6.1 | 7.0 | 7.3 | 6.5 | 4.9 | 3.2 | 2.1 | 1.7 |
| Level | Dim | Moderate | Bright | Bright | Intense | Intense | Intense | Intense | Bright | Moderate | Moderate | Dim |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 1.9 | Dim |
| Feb | 2.9 | Moderate |
| Mar | 4.1 | Bright |
| Apr | 5.1 | Bright |
| May | 6.1 | Intense |
| Jun | 7.0 | Intense |
| Jul | 7.3 | Intense |
| Aug | 6.5 | Intense |
| Sep | 4.9 | Bright |
| Oct | 3.2 | Moderate |
| Nov | 2.1 | Moderate |
| Dec | 1.7 | Dim |
Where is Viseu?
Viseu sits at 40.7°N, 7.9°W, 469 m above sea level, in Portugal. The nearest listed city is Arouca, 41 km away.
Topography around Viseu
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Viseu.
Within 3 km, the terrain around Viseu has only modest variations in elevation — a maximum elevation change of 165 m around an average of 466 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 814 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,993 m.
The land around Viseu is covered by trees (45%) and artificial surfaces (35%) within 3 km, trees (56%) and grassland (36%) within 16 km, and trees (48%) and grassland (41%) 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 Viseu (40.6617°, -7.909°, elevation 469 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. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).