Arrentela weather in September

In September, Arrentela sees average daytime highs of 23°C and overnight lows near 18°C, with 25 mm of rain across 3.6 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 64% 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 Arrentela's 4th-clearest and 12th-windiest month. For the whole year in context, see Arrentela's year-round climate.

Daytime high
23°
3rd warmest
Overnight low
18°
10th coldest
Rainfall
25 mm
3.6 wet days
Daylight
12 h 12 min
6:23 AM – 6:38 PM
Cloud cover
33%
4th clearest
Wind
15 km/h
12th windiest
Solar energy
5.37 kWh/m²
Travel score
8.5
out of 10

Arrentela is human settlement in Portugal.

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 Arrentela reaches about 23°C in the afternoon and slips back to 18°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 21°C and 26°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)
12418
22418
32418
42418
52418
62418
72418
82418
92418
102418
112418
122418
132418
142418
152318
162318
172318
182317
192317
202317
212317
222317
232317
242317
252317
262317
272317
282217
292217
302217

Arrentela 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° / 10°638.49.64.6
Feb15° / 10°486.610.54.9
Mar17° / 12°48711.75.9
Apr18° / 13°457.4136.3
May20° / 15°355.114.17.3
Jun23° / 17°81.514.68.7
Jul25° / 18°10.414.49.4
Aug25° / 18°30.613.59.2
Sep23° / 18°253.612.38.5
Oct21° / 16°708.1116.9
Nov17° / 13°748.89.95.9
Dec15° / 11°779.19.44.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 64% 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 21%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18812
28713
38713
48614
58515
68515
78515
88317
98317
108218
118218
128119
138119
148119
158020
168020
177921
187822
197723
207624
217624
227525
237525
247426
257327
267228
277228
287129
297030
307030

Chance of precipitation in September

Any precipitation

Arrentela gets around 25 mm of rain over 3.6 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 11% and peaks near 17% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%151015202530
Rain chance (%)
14
24
34
44
55
65
76
86
97
108
119
1210
1310
1411
1512
1613
1713
1814
1915
2015
2116
2216
2317
2417
2517
2617
2717
2817
2917
3017

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 43% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1738505
2838495
3838495
4838485
5938485
6938475
7938475
81038475
91038465
101138465
111138465
121138455
131238455
141338445
151338445
161438435
171438435
181538424
191539424
201539414
211540414
221640404
231641394
241641384
251642374
261742364
271843354
281943344
292043334
302143324

Wind in September

Winds average 15 km/h in September, the calmest month.

Across September, daily wind ranges from about 15 km/h on the calmest days to 15 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2215light breeze
2315light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2915light breeze
3015light 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 6:10 AM to 6:36 AM, and sunset from 7:03 PM to 6:15 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.96:107:03
212.86:117:01
312.86:126:59
412.86:126:58
512.76:136:56
612.76:146:55
712.66:156:53
812.66:166:51
912.56:176:50
1012.56:186:48
1112.56:196:46
1212.46:206:45
1312.46:216:43
1412.36:216:41
1512.36:226:40
1612.26:236:38
1712.26:246:36
1812.26:256:35
1912.16:266:33
2012.16:276:32
2112.06:286:30
2212.06:296:28
2311.96:306:27
2411.96:316:25
2511.96:326:23
2611.86:336:22
2711.86:336:20
2811.76:346:18
2911.76:356:17
3011.66:366:15

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.37 kWh/m².

For context, solar energy here swings from a low near 2.08 kWh/m² to a high of 7.69 kWh/m² in July across the year — September's 5.37 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.2Intense
26.1Intense
36.1Intense
46.0Intense
56.0Bright
65.9Bright
75.9Bright
85.8Bright
95.8Bright
105.7Bright
115.6Bright
125.6Bright
135.5Bright
145.5Bright
155.4Bright
165.3Bright
175.3Bright
185.2Bright
195.2Bright
205.1Bright
215.0Bright
225.0Bright
234.9Bright
244.9Bright
254.8Bright
264.8Bright
274.7Bright
284.7Bright
294.6Bright
304.6Bright
Planning a trip in September

Is September a good time to visit Arrentela?

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

8.5
Sightseeing
4th-best month of the year
6.7
Beach & pool
3rd-best month of the year

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

What to pack for Arrentela in September

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

In September, Arrentela sees daytime highs around 23°C and nights near 18°C. Worth packing: light clothes and sun protection. About 4 days see rain.

light clothessun protection

Sea temperature near Arrentela in September

The nearest coast averages about 19°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 24 km away) is warmest in September at about 19°C and coldest in February near 15°C.

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

14°16°18°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan15Cool
Feb15Bracing
Mar15Bracing
Apr15Cool
May16Cool
Jun18Cool
Jul18Cool
Aug19Cool
Sep19Cool
Oct18Cool
Nov17Cool
Dec16Cool

UV index in Arrentela in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Arrentela peaks around July 15 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 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 highHighModerateJul 15UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar6High
Apr8Very high
May7Very high
Jun9Very high
Jul9Very high
Aug9Very high
Sep6High
Oct5High
Nov3Moderate
Dec2Low
Location & terrain

Where is Arrentela?

Arrentela sits at 38.6°N, 9.1°W, 30 m above sea level, in Portugal. The nearest listed city is Amora, 1.0 km away.

Topography around Arrentela

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

Within 3 km, the terrain around Arrentela has only modest variations in elevation — a maximum elevation change of 53 m around an average of 17 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 248 m; within 80 km, large variations in elevation — a maximum elevation change of 651 m.

The land around Arrentela is covered by artificial surfaces (32%) and grassland (28%) within 3 km, water (30%), grassland (27%) and artificial surfaces (20%) within 16 km, and water (39%) and grassland (32%) within 80 km.

3 km
53 m
16 km
248 m
80 km
651 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Amora 1.0 km · Corroios 5.0 km · Barreiro 5.0 km · Laranjeiro 6.0 km · Lavradio 6.0 km · Piedade 7.0 km · Almada 8.0 km · Charneca de Caparica 8.0 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 Arrentela (38.625°, -9.1015°, elevation 30 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).