Viseu weather in September

In September, Viseu sees average daytime highs of 31°C and overnight lows near 24°C, with 27 mm of rain across 9.3 wet days and about 12 hours of daylight. It is the 4th-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 31°C through the month. The sky is clear or mostly clear about 59% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 hours at the start of September to 12 hours by month's end. Set against the rest of the year, September is Viseu's 1st-clearest and 1st-windiest month. For the whole year in context, see Viseu's year-round climate.

Daytime high
31°
4th warmest
Overnight low
24°
9th coldest
Rainfall
27 mm
9.3 wet days
Daylight
12 hours
5:59 AM – 5:59 PM
Cloud cover
40%
1st clearest
Wind
14 km/h
1st windiest
Solar energy
6.22 kWh/m²
Travel score
4.8
out of 10

Viseu is human settlement in Brazil.

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 31°C through the month.

A typical September day in Viseu reaches about 31°C in the afternoon and slips back to 24°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 30°C and 32°C. Set against its neighbours, September runs on par with August and on par with October.

20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13124
23124
33124
43124
53124
63124
73124
83124
93124
103124
113124
123124
133124
143124
153124
163124
173124
183124
193124
203124
213124
223124
233124
243124
253124
263124
273124
283124
293124
303124

How September really feels in Viseu

Once humidity and wind are folded in, September averages 30 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
30
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Viseu weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 24°25626.712.13.1
Feb29° / 24°36926.9122.9
Mar29° / 23°47830.3122.8
Apr29° / 24°49129.4122.8
May30° / 24°32028.511.93.0
Jun30° / 23°16025.111.93.3
Jul30° / 23°11623.911.93.6
Aug30° / 24°5018.3124.2
Sep31° / 24°279.3124.8
Oct31° / 24°216.1124.9
Nov31° / 24°297.212.14.6
Dec31° / 24°7916.112.13.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 59% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 29% of September, with mostly cloudy or overcast conditions the remaining 12%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18911
29010
39010
49010
59010
69010
79010
89010
99010
109010
119010
129010
139010
148911
158911
168911
178812
188812
198812
208713
218713
228713
238713
248713
258713
268614
278614
288614
298515
308515

Chance of precipitation in September

Any precipitation

Viseu gets around 27 mm of rain over 9.3 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 31% and peaks near 47% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
147
246
345
443
542
641
740
838
937
1036
1135
1234
1333
1432
1531
1630
1729
1828
1927
2026
2125
2224
2323
2422
2521
2621
2720
2820
2920
3019

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the oppressive band about 98% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
1955
2955
3964
4964
5973
6973
7973
8973
9973
10973
11982
12982
13982
14982
15982
16982
17982
18982
19982
20991
21991
22991
23991
24991
25991
26991
27991
28991
29991
30991

Wind in September

Winds average 14 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 13 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
514light breeze
614light breeze
714light breeze
814light breeze
914light breeze
1014light breeze
1114light breeze
1214light breeze
1314light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1814light breeze
1914light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 hours at the start of September to 12 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 0 minutes over September. Sunrise moves from 6:05 AM to 5:54 AM, and sunset from 6:04 PM to 5:54 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.06:056:04
212.06:056:03
312.06:046:03
412.06:046:03
512.06:036:02
612.06:036:02
712.06:036:02
812.06:026:01
912.06:026:01
1012.06:026:01
1112.06:016:00
1212.06:016:00
1312.06:006:00
1412.06:005:59
1512.05:595:59
1612.05:595:59
1712.05:595:58
1812.05:585:58
1912.05:585:58
2012.05:575:57
2112.05:575:57
2212.05:575:57
2312.05:565:56
2412.05:565:56
2512.05:555:56
2612.05:555:55
2712.05:555:55
2812.05:545:55
2912.05:545:54
3012.05:545:54

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.22 kWh/m².

For context, solar energy here swings from a low near 4.28 kWh/m² to a high of 6.36 kWh/m² in October across the year — September's 6.22 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.0Intense
26.1Intense
36.1Intense
46.1Intense
56.1Intense
66.1Intense
76.1Intense
86.1Intense
96.1Intense
106.1Intense
116.2Intense
126.2Intense
136.2Intense
146.2Intense
156.2Intense
166.2Intense
176.2Intense
186.2Intense
196.3Intense
206.3Intense
216.3Intense
226.3Intense
236.3Intense
246.3Intense
256.3Intense
266.3Intense
276.3Intense
286.3Intense
296.3Intense
306.4Intense
Planning a trip in September

Hazard calendar for Viseu

In seasonPeak

None of Viseu's seasonal hazards are active in September. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Viseu's monsoon runs January–May, when most of the year's rain falls.

Monsoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Viseu?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

4.8
Sightseeing
2nd-best month of the year
7.0
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Viseu for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Viseu in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Viseu sees daytime highs around 31°C and nights near 24°C. Pack light clothes and sun protection. Worth having: rain gear. About 9 days see rain.

light clothessun protectionrain gear

Sea temperature near Viseu in September

The nearest coast averages about 28°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 31 km away) is warmest in May at about 29°C and coldest in September near 28°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan28Tropical
Feb28Tropical
Mar28Tropical
Apr29Tropical
May29Tropical
Jun29Tropical
Jul28Tropical
Aug28Warm
Sep28Warm
Oct28Warm
Nov28Tropical
Dec28Tropical

UV index in Viseu in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Viseu peaks around March 17 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 19 at about 10 (extreme).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 17UV 15Jul 19UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar15Extreme
Apr14Extreme
May12Extreme
Jun11Extreme
Jul10Extreme
Aug11Extreme
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec11Extreme

Air quality in Viseu in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Viseu is worst in February — around 19 µg/m³ PM2.5 (moderate), about 2.9× the cleanest month (July, 7 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateFeb 2019 µg/m³Jul 127 µg/m³
PM2.5 (µg/m³)Level
Jan16Moderate
Feb19Moderate
Mar19Moderate
Apr14Moderate
May8Good
Jun7Good
Jul7Good
Aug8Good
Sep10Good
Oct12Good
Nov18Moderate
Dec18Moderate
Location & terrain

Where is Viseu?

Viseu sits at 1.2°S, 46.1°W, 13 m above sea level, in Brazil. The nearest listed city is Carutapera, 13 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 47 m around an average of 13 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 89 m; within 80 km, only modest variations in elevation — a maximum elevation change of 180 m.

The land around Viseu is covered by trees (41%) and grassland (22%) within 3 km, trees (36%) and mangroves (34%) within 16 km, and trees (35%) and water (34%) within 80 km.

3 km
47 m
16 km
89 m
80 km
180 m
treesgrasslandartificial surfaceswaterwetlandmangroves
September weather nearby: Carutapera 13 km · Cândido Mendes 54 km · Augusto Corrêa 58 km · Bragança 71 km · Cachoeira do Piriá 77 km · Tracuateua 86 km · Santa Luzia do Pará 92 km · Maracaçumé 96 km

Brazil travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / N
127 / 220 V · 60 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$10,713
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
89%
of population, 2024
Homicide rate
19.3
per 100k, 2023
Road deaths
16
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 482
Religion
Roman Catholic 57%Evangelical 27%none 9%other 4%

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 (-1.1967°, -46.14°, elevation 13 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. 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).