Sestao weather in September

In September, Sestao sees average daytime highs of 21°C and overnight lows near 15°C, with 65 mm of rain across 11.8 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 22°C in the first days to 20°C by the end. The sky is clear or mostly clear about 30% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Sestao's 2nd-clearest and 9th-windiest month. For the whole year in context, see Sestao's year-round climate.

Daytime high
21°
3rd warmest
Overnight low
15°
10th coldest
Rainfall
65 mm
11.8 wet days
Daylight
12 h 18 min
6:58 AM – 7:15 PM
Cloud cover
56%
2nd clearest
Wind
10 km/h
9th windiest
Solar energy
4.14 kWh/m²
Travel score
6.2
out of 10

Sestao is capital of Sestao Municipality, Spain.

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 22°C in the first days to 20°C by the end.

A typical September day in Sestao reaches about 21°C in the afternoon and slips back to 15°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 17°C and 25°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)
12216
22216
32216
42216
52215
62215
72215
82215
92115
102115
112115
122115
132115
142115
152115
162115
172115
182115
192114
202114
212114
222014
232014
242014
252014
262014
272014
282014
292014
302014

Sestao weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan11° / 11214.819.22.4
Feb12° / 10013.61.510.22.6
Mar13° / 9813.50.611.63.5
Apr15° / 9715.2013.23.8
May17° / 11°8414.2014.55.0
Jun20° / 14°6911.4015.16.0
Jul22° / 16°6010.4014.96.6
Aug23° / 16°5510.3013.86.8
Sep21° / 15°6511.8012.36.2
Oct18° / 12°9713.9010.85.4
Nov14° / 13515.60.19.53.5
Dec12° / 10514.40.48.82.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 20% of September, with mostly cloudy or overcast conditions the remaining 50%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15248
25248
35347
45347
55347
65347
75347
85347
95347
105347
115248
125347
135248
145248
155149
165149
175050
184951
194951
204852
214852
224951
234852
244852
254654
264654
274654
284555
294555
304456

Chance of precipitation in September

Any precipitation

Sestao gets around 65 mm of rain over 11.8 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 40% and peaks near 45% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
134
234
334
435
535
635
736
836
937
1037
1138
1238
1339
1439
1540
1640
1741
1841
1942
2042
2142
2243
2343
2443
2544
2644
2744
2845
2945
3045

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the comfortable band about 38% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
118373510
21938349
32038339
42138329
52338318
62438318
72538307
82638307
92737296
102837296
112937285
123136285
133236275
143336274
153437263
163537253
173638252
183638242
193739222
203839211
213940201
223940201
234041191
244141180
254141170
264241160
274440160
284540150
294739140
304838130

Wind in September

Winds average 10 km/h in September.

Across September, daily wind ranges from about 9 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2410calm
2510calm
2611calm
2711calm
2811calm
2911calm
3011calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours 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 84 minutes over September. Sunrise moves from 6:41 AM to 7:14 AM, and sunset from 7:43 PM to 6:49 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.06:417:43
213.06:427:41
312.96:437:39
412.96:447:38
512.86:457:36
612.86:467:34
712.76:477:32
812.76:487:30
912.66:507:28
1012.66:517:26
1112.56:527:25
1212.56:537:23
1312.46:547:21
1412.46:557:19
1512.36:567:17
1612.36:587:15
1712.26:597:13
1812.27:007:11
1912.17:017:09
2012.17:027:08
2112.07:037:06
2212.07:057:04
2311.97:067:02
2411.97:077:00
2511.87:086:58
2611.87:096:56
2711.77:106:54
2811.77:126:53
2911.67:136:51
3011.67:146:49

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.14 kWh/m².

For context, solar energy here swings from a low near 1.4 kWh/m² to a high of 5.84 kWh/m² in June across the year — September's 4.14 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.6Bright
34.6Bright
44.6Bright
54.5Bright
64.5Bright
74.5Bright
84.4Bright
94.4Bright
104.3Bright
114.3Bright
124.3Bright
134.2Bright
144.2Bright
154.1Bright
164.1Bright
174.0Bright
184.0Bright
194.0Moderate
203.9Moderate
213.9Moderate
223.8Moderate
233.8Moderate
243.8Moderate
253.7Moderate
263.7Moderate
273.6Moderate
283.6Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Is September a good time to visit Sestao?

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

6.2
Sightseeing
3rd-best month of the year
3.7
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Sestao for sightseeing.

What to pack for Sestao in September

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

In September, Sestao sees daytime highs around 21°C and nights near 15°C. Worth packing: rain gear. About 12 days see rain.

rain gear

Sea temperature near Sestao in September

The nearest coast averages about 20°C in September — 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 22°C and coldest in February near 13°C.

It's comfortable for a long swim from Jul 11 to Sep 21 — about 2.4 months when the water holds above 20°C.

10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb13Bracing
Mar13Bracing
Apr13Bracing
May15Cool
Jun18Cool
Jul21Refreshing
Aug22Refreshing
Sep20Refreshing
Oct18Cool
Nov16Cool
Dec14Bracing

UV index in Sestao 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 Sestao peaks around July 15 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 15UV 9Dec 22UV 1
UV index (midday)Level
Jan2Low
Feb2Low
Mar5Moderate
Apr6High
May6High
Jun8Very high
Jul9Very high
Aug8Very high
Sep5High
Oct4Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Sestao?

Sestao sits at 43.3°N, 3.0°W, 65 m above sea level, in Spain. The nearest listed city is Portugalete, 2.0 km away.

Topography around Sestao

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

Within 3 km, the terrain around Sestao has significant variations in elevation — a maximum elevation change of 364 m around an average of 37 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 994 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,676 m.

The land around Sestao is covered by artificial surfaces (52%) and trees (26%) within 3 km, trees (54%) within 16 km, and trees (39%) and water (32%) within 80 km.

3 km
364 m
16 km
994 m
80 km
1,676 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Portugalete 2.0 km · Barakaldo 2.0 km · Leioa 2.0 km · Erandio 3.0 km · Santurtzi 3.0 km · Algorta 4.0 km · Getxo 5.0 km · Bilbao 8.0 km

Spain travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 65% of US
price level, 2025
GDP per capita
$38,627
2025
Happiness
6.5 / 10
World Happiness, 2025
Safe drinking water
99%
of population, 2024
Homicide rate
0.7
per 100k, 2023
Road deaths
3.9
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 540
Religion
Roman Catholic 58%atheist 16%agnostic 11%non-believer 11%

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 Sestao (43.3098°, -3.0072°, elevation 65 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).