Ílhavo weather in September

In September, Ílhavo sees average daytime highs of 23°C and overnight lows near 16°C, with 48 mm of rain across 5.6 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 24°C in the first days to 22°C by the end. The sky is clear or mostly clear about 58% of the time in September, and the air most often feels humid.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Ílhavo's 3rd-clearest and 12th-windiest month. For the whole year in context, see Ílhavo's year-round climate.

Daytime high
23°
3rd warmest
Overnight low
16°
10th coldest
Rainfall
48 mm
5.6 wet days
Daylight
12 h 18 min
6:21 AM – 6:37 PM
Cloud cover
38%
3rd clearest
Wind
13 km/h
12th windiest
Solar energy
5.01 kWh/m²
Travel score
7.9
out of 10

Ílhavo is city seat of Ílhavo municipality.

Air quality
Good
PM10 23.2 µg/m³ · 2019

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 24°C in the first days to 22°C by the end.

A typical September day in Ílhavo reaches about 23°C in the afternoon and slips back to 16°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 27°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12417
22417
32417
42417
52417
62417
72417
82417
92416
102416
112316
122316
132316
142316
152316
162316
172316
182316
192316
202316
212216
222216
232216
242216
252216
262216
272215
282215
292215
302215

Ílhavo weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan14° / 11911.69.43.9
Feb15° / 83910.44.4
Mar17° / 10°889.711.75.4
Apr18° / 11°9210.7135.7
May20° / 13°72914.26.6
Jun22° / 16°244.714.87.9
Jul24° / 17°102.214.68.9
Aug24° / 17°153.113.68.7
Sep23° / 16°485.612.37.9
Oct20° / 14°13211.410.96.2
Nov16° / 11°13312.59.75.0
Dec14° / 12911.29.14.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 58% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 28%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18119
28119
38119
48119
58020
68020
77822
87822
97723
107723
117624
127525
137426
147426
157327
167228
177129
187030
197030
206931
216832
226733
236733
246733
256535
266535
276535
286436
296436
306436

Chance of precipitation in September

Any precipitation

Ílhavo gets around 48 mm of rain over 5.6 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 19% and peaks near 25% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
111
211
311
412
512
612
713
813
914
1015
1116
1217
1318
1419
1519
1620
1721
1822
1922
2023
2123
2224
2324
2424
2525
2625
2725
2825
2925
3025

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the humid band about 42% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
11033552
21034542
31034542
41134532
51135522
61235512
71236502
81237492
91337482
101338472
111439462
121439452
131440442
141541432
151542422
161643401
171643391
181744381
191744371
201845361
211845361
221946351
231946341
241946341
252047331
262047321
272147311
282247301
292347291
302447281

Wind in September

Winds average 13 km/h in September, the calmest month.

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
114light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1313light breeze
1413light breeze
1513light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3014light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 min at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over September. Sunrise moves from 6:06 AM to 6:35 AM, and sunset from 7:03 PM to 6:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.96:067:03
212.96:077:01
312.96:086:59
412.86:096:58
512.86:106:56
612.76:116:54
712.76:126:53
812.66:136:51
912.66:146:49
1012.56:156:47
1112.56:166:46
1212.46:176:44
1312.46:186:42
1412.46:196:40
1512.36:206:39
1612.36:216:37
1712.26:226:35
1812.26:236:33
1912.16:246:32
2012.16:256:30
2112.06:266:28
2212.06:276:26
2311.96:286:25
2411.96:296:23
2511.96:306:21
2611.86:316:19
2711.86:326:18
2811.76:336:16
2911.76:346:14
3011.66:356:13

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.01 kWh/m².

For context, solar energy here swings from a low near 1.8 kWh/m² to a high of 7.33 kWh/m² in July across the year — September's 5.01 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.8Bright
25.8Bright
35.7Bright
45.7Bright
55.6Bright
65.5Bright
75.5Bright
85.4Bright
95.4Bright
105.3Bright
115.3Bright
125.2Bright
135.1Bright
145.1Bright
155.0Bright
165.0Bright
174.9Bright
184.8Bright
194.8Bright
204.7Bright
214.7Bright
224.6Bright
234.6Bright
244.5Bright
254.5Bright
264.4Bright
274.4Bright
284.3Bright
294.3Bright
304.3Bright
Planning a trip in September

Hazard calendar for Ílhavo

In seasonPeak

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

Ílhavo's rainy season runs October–May, when most of the year's rain falls.

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

Is September a good time to visit Ílhavo?

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

7.9
Sightseeing
3rd-best month of the year
6.0
Beach & pool
3rd-best month of the year

September is one of the better times to visit Ílhavo for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Ílhavo in September

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

In September, Ílhavo sees daytime highs around 23°C and nights near 16°C. Worth packing: light clothes and sun protection. About 6 days see rain.

light clothessun protection

Sea temperature near Ílhavo in September

The nearest coast averages about 18°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 17 km away) is warmest in August at about 18°C and coldest in February near 14°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

12°14°16°18°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan14Bracing
Feb14Bracing
Mar14Bracing
Apr15Bracing
May16Cool
Jun17Cool
Jul18Cool
Aug18Cool
Sep18Cool
Oct17Cool
Nov16Cool
Dec15Bracing

UV index in Ílhavo in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Ílhavo peaks around July 11 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 9Dec 20UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7High
Jun9Very high
Jul9Very high
Aug8Very high
Sep5High
Oct4Moderate
Nov2Moderate
Dec2Low

Air quality in Ílhavo 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 Ílhavo is worst in October — around 19 µg/m³ PM2.5 (moderate), about 2.8× the cleanest month (November, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodOct 1119 µg/m³Nov 237 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb9Good
Mar11Good
Apr10Good
May8Good
Jun12Good
Jul8Good
Aug14Moderate
Sep17Moderate
Oct19Moderate
Nov7Good
Dec7Good
Location & terrain

Where is Ílhavo?

Ílhavo sits at 40.6°N, 8.7°W, 13 m above sea level, in Portugal. The nearest listed city is Vilar, 4.0 km away.

Topography around Ílhavo

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Ílhavo.

Within 3 km, the terrain around Ílhavo has only modest variations in elevation — a maximum elevation change of 55 m around an average of 14 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 126 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,365 m.

The land around Ílhavo is covered by grassland (23%), trees (21%) and artificial surfaces (20%) within 3 km, water (31%) and trees (30%) within 16 km, and trees (46%) and water (27%) within 80 km.

3 km
55 m
16 km
126 m
80 km
1,365 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Vilar 4.0 km · Aveiro 5.0 km · Ovar 29 km · São João da Madeira 37 km · Feira 38 km · Eiras 45 km · Espinho 45 km · São Paulo de Frades 46 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
Catholic 68%not applicable 13%no religion 12%no response 2%

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 Ílhavo (40.6019°, -8.6702°, 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).