Sant Boi de Llobregat weather in September

In September, Sant Boi de Llobregat sees average daytime highs of 24°C and overnight lows near 20°C, with 86 mm of rain across 9.9 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 2nd-wettest month of the year here.

Highs ease over the month, from about 25°C in the first days to 22°C by the end. The sky is clear or mostly clear about 48% of the time in September, and the air most often feels humid.

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 Sant Boi de Llobregat's 5th-clearest and 9th-windiest month. For the whole year in context, see Sant Boi de Llobregat's year-round climate.

Daytime high
24°
3rd warmest
Overnight low
20°
10th coldest
Rainfall
86 mm
9.9 wet days
Daylight
12 h 18 min
6:38 AM – 6:54 PM
Cloud cover
46%
5th clearest
Wind
12 km/h
9th windiest
Solar energy
4.6 kWh/m²
Travel score
7.1
out of 10

Sant Boi de Llobregat is human settlement in Sant Boi de Llobregat, Baix Llobregat, Àmbit metropolità de Barcelona, 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 25°C in the first days to 22°C by the end.

A typical September day in Sant Boi de Llobregat reaches about 24°C in the afternoon and slips back to 20°C overnight — a 4°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.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12521
22521
32521
42521
52521
62521
72421
82421
92421
102420
112420
122420
132420
142420
152420
162420
172320
182319
192319
202319
212319
222319
232319
242319
252319
262219
272218
282218
292218
302218

Sant Boi de Llobregat weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan13° / 456.79.43.8
Feb13° / 365.810.34.0
Mar14° / 10°40611.74.8
Apr16° / 12°487.613.15.4
May19° / 15°436.614.36.7
Jun23° / 19°294.714.98.0
Jul25° / 22°224.614.78.3
Aug26° / 22°446.413.77.7
Sep24° / 20°869.912.37.1
Oct20° / 16°9410.110.96.5
Nov16° / 12°647.89.75.5
Dec13° / 446.49.14.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 48% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 33%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17228
27030
37030
47030
56931
66931
76931
86832
96832
106832
116733
126733
136733
146634
156634
166634
176634
186634
196535
206535
216535
226535
236436
246436
256436
266535
276535
286535
296535
306535

Chance of precipitation in September

Any precipitation

Sant Boi de Llobregat gets around 86 mm of rain over 9.9 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 33% and peaks near 34% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
130
230
331
432
532
632
733
833
933
1033
1133
1233
1334
1434
1534
1634
1734
1834
1934
2034
2134
2233
2333
2432
2532
2631
2731
2831
2931
3031

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 35% of days. Sticky, muggy-or-worse air turns up on roughly 37% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
129264518
229274516
3310284514
4310294512
5411304510
641130459
751231457
851331446
961431445
1061532435
1171632414
1281733403
1381733393
1491833373
1591934352
16102035342
17102135322
18112236302
19122236282
20122337261
21132438251
22132439231
23132539211
24142540201
25142541191
26152541181
27162542171
28172542161
29182542151
30192541151

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 11 km/h on the calmest days to 12 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
512calm
612calm
712calm
812calm
912calm
1012calm
1112calm
1212calm
1312calm
1412calm
1512calm
1612calm
1712calm
1812calm
1912calm
2012calm
2112calm
2212calm
2312calm
2412calm
2512calm
2612calm
2712calm
2812calm
2912calm
3012calm

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 6:22 AM to 6:53 AM, and sunset from 7:21 PM to 6:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.06:227:21
212.96:237:19
312.96:257:17
412.86:267:16
512.86:277:14
612.76:287:12
712.76:297:10
812.66:307:09
912.66:317:07
1012.66:327:05
1112.56:337:03
1212.56:347:01
1312.46:357:00
1412.46:366:58
1512.36:376:56
1612.36:386:54
1712.26:396:53
1812.26:406:51
1912.16:416:49
2012.16:426:47
2112.06:436:45
2212.06:446:44
2311.96:456:42
2411.96:466:40
2511.86:476:38
2611.86:496:36
2711.86:506:35
2811.76:516:33
2911.76:526:31
3011.66:536:29

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.6 kWh/m².

For context, solar energy here swings from a low near 1.9 kWh/m² to a high of 7.14 kWh/m² in June across the year — September's 4.6 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.3Bright
25.2Bright
35.2Bright
45.1Bright
55.1Bright
65.0Bright
75.0Bright
85.0Bright
94.9Bright
104.9Bright
114.8Bright
124.8Bright
134.7Bright
144.7Bright
154.6Bright
164.6Bright
174.5Bright
184.5Bright
194.5Bright
204.4Bright
214.4Bright
224.3Bright
234.3Bright
244.2Bright
254.2Bright
264.2Bright
274.1Bright
284.1Bright
294.0Bright
304.0Moderate
Planning a trip in September

Is September a good time to visit Sant Boi de Llobregat?

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

7.1
Sightseeing
4th-best month of the year
5.8
Beach & pool
4th-best month of the year

September is one of the better times to visit Sant Boi de Llobregat for general sightseeing.

What to pack for Sant Boi de Llobregat in September

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

In September, Sant Boi de Llobregat sees daytime highs around 24°C and nights near 20°C. Worth packing: light clothes, rain gear and sun protection. About 10 days see rain.

light clothesrain gearsun protection

Sea temperature near Sant Boi de Llobregat in September

The nearest coast averages about 24°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 25 km away) is warmest in August at about 26°C and coldest in February near 13°C.

It's comfortable for a long swim from Jun 8 to Oct 26 — about 4.6 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan14Bracing
Feb13Bracing
Mar14Bracing
Apr15Bracing
May17Cool
Jun21Refreshing
Jul24Warm
Aug26Warm
Sep24Warm
Oct21Refreshing
Nov18Cool
Dec15Cool

UV index in Sant Boi de Llobregat 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 Sant Boi de Llobregat peaks around July 14 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 14UV 9Dec 19UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr7High
May6High
Jun8Very high
Jul9Very high
Aug8Very high
Sep6High
Oct4Moderate
Nov2Moderate
Dec1Low
Location & terrain

Where is Sant Boi de Llobregat?

Sant Boi de Llobregat sits at 41.3°N, 2.0°E, 45 m above sea level, in Spain. The nearest listed city is Sant Joan Despí, 3.0 km away.

Topography around Sant Boi de Llobregat

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Sant Boi de Llobregat.

Within 3 km, the terrain around Sant Boi de Llobregat has significant variations in elevation — a maximum elevation change of 276 m around an average of 42 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 650 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,677 m.

The land around Sant Boi de Llobregat is covered by artificial surfaces (35%) and trees (31%) within 3 km, trees (35%), water (28%) and artificial surfaces (22%) within 16 km, and trees (38%) and water (34%) within 80 km.

3 km
276 m
16 km
650 m
80 km
1,677 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Sant Joan Despí 3.0 km · Viladecans 4.0 km · Cornellà de Llobregat 4.0 km · Sant Feliu de Llobregat 5.0 km · Gavà 5.0 km · El Prat de Llobregat 5.0 km · Sant Just Desvern 5.0 km · L'Hospitalet de Llobregat 6.0 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 Sant Boi de Llobregat (41.3436°, 2.0366°, elevation 45 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).