Gujan-Mestras weather in September

In September, Gujan-Mestras sees average daytime highs of 23°C and overnight lows near 15°C, with 63 mm of rain across 9 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 24°C in the first days to 21°C by the end. The sky is clear or mostly clear about 38% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 13 h 06 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Gujan-Mestras's 3rd-clearest and 10th-windiest month. For the whole year in context, see Gujan-Mestras's year-round climate.

Daytime high
23°
4th warmest
Overnight low
15°
9th coldest
Rainfall
63 mm
9 wet days
Daylight
12 h 18 min
6:49 AM – 7:08 PM
Cloud cover
50%
3rd clearest
Wind
10 km/h
10th windiest
Solar energy
4.25 kWh/m²
Travel score
7.0
out of 10

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 21°C by the end.

A typical September day in Gujan-Mestras reaches about 23°C in the afternoon and slips back to 15°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 19°C and 28°C. Set against its neighbours, September runs about 3°C cooler than August and about 4°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12516
22516
32516
42416
52416
62416
72416
82416
92416
102415
112415
122315
132315
142315
152315
162315
172315
182315
192315
202215
212214
222214
232214
242214
252214
262214
272114
282114
292114
302114

Gujan-Mestras weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan10° / 7211.592.3
Feb11° / 529.410.12.8
Mar14° / 5410.711.64.2
Apr17° / 661213.25.0
May20° / 13°7011.614.66.0
Jun23° / 16°639.315.37.0
Jul25° / 18°467.8157.3
Aug26° / 18°53813.97.3
Sep23° / 15°63912.37.0
Oct19° / 12°7310.610.75.9
Nov14° / 8812.59.43.7
Dec11° / 7711.88.72.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% 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 44%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16139
26139
36139
46139
56139
66139
76040
86139
96040
106040
115941
125842
135842
145743
155743
165644
175644
185644
195545
205545
215446
225446
235347
245347
255149
265149
275050
284951
294951
304753

Chance of precipitation in September

Any precipitation

Gujan-Mestras gets around 63 mm of rain over 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 31% and peaks near 33% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
125
226
326
426
526
627
727
828
929
1030
1130
1231
1331
1432
1532
1633
1733
1833
1933
2033
2133
2233
2333
2433
2533
2633
2733
2833
2933
3033

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 41% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
122382812
223382711
324392710
425392610
52639259
62740258
72840258
82940247
92940246
103040246
113041245
123141245
133140244
143240244
153340243
163440243
173440232
183540232
193641222
203641211
213741211
223742201
233742201
243742201
253743191
263843191
273842181
283942181
294042171
304142161

Wind in September

Winds average 10 km/h in September.

Across September, daily wind ranges from about 10 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
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2410calm
2510calm
2610calm
2710calm
2810calm
2910calm
3011calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 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 90 minutes over September. Sunrise moves from 6:31 AM to 7:07 AM, and sunset from 7:37 PM to 6:40 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.16:317:37
213.06:327:35
313.06:347:33
412.96:357:31
512.96:367:29
612.86:377:27
712.86:397:25
812.76:407:23
912.76:417:21
1012.66:427:19
1112.66:437:18
1212.56:457:16
1312.56:467:14
1412.46:477:12
1512.46:487:10
1612.36:497:08
1712.36:517:06
1812.26:527:04
1912.16:537:02
2012.16:547:00
2112.06:566:58
2212.06:576:56
2311.96:586:54
2411.96:596:52
2511.87:006:50
2611.87:026:48
2711.77:036:46
2811.77:046:44
2911.67:056:42
3011.67:076:40

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.25 kWh/m².

For context, solar energy here swings from a low near 1.25 kWh/m² to a high of 6.27 kWh/m² in June across the year — September's 4.25 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
15.0Bright
24.9Bright
34.9Bright
44.8Bright
54.8Bright
64.7Bright
74.7Bright
84.6Bright
94.6Bright
104.5Bright
114.5Bright
124.4Bright
134.3Bright
144.3Bright
154.2Bright
164.2Bright
174.1Bright
184.1Bright
194.0Bright
204.0Moderate
213.9Moderate
223.9Moderate
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 Gujan-Mestras?

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

7.0
Sightseeing
3rd-best month of the year
5.4
Beach & pool
4th-best month of the year

September is one of the better times to visit Gujan-Mestras for general sightseeing.

What to pack for Gujan-Mestras in September

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

In September, Gujan-Mestras sees daytime highs around 23°C and nights near 15°C. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

Sea temperature near Gujan-Mestras 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 at the nearest coast (about 24 km away) is warmest in August at about 22°C and coldest in February near 12°C.

It's comfortable for a long swim from Jul 7 to Sep 18 — about 2.4 months when the water holds above 20°C.

10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingcomfortable to swim
Sea temperature (°C)Comfort
Jan12Bracing
Feb12Bracing
Mar12Bracing
Apr13Bracing
May16Cool
Jun18Cool
Jul21Refreshing
Aug22Refreshing
Sep20Refreshing
Oct18Cool
Nov16Cool
Dec14Bracing

UV index in Gujan-Mestras 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 Gujan-Mestras peaks around July 18 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 1 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 highModerateLowJul 18UV 8Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr6High
May6High
Jun7Very high
Jul8Very high
Aug7Very high
Sep5Moderate
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Gujan-Mestras?

Gujan-Mestras sits at 44.6°N, 1.1°W, 5 m above sea level, in France. The nearest listed city is La Teste-de-Buch, 6.0 km away.

Topography around Gujan-Mestras

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

Within 3 km, the terrain around Gujan-Mestras has only modest variations in elevation — a maximum elevation change of 26 m around an average of 6 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 96 m; within 80 km, only modest variations in elevation — a maximum elevation change of 149 m.

The land around Gujan-Mestras is covered by water (28%), trees (27%) and artificial surfaces (27%) within 3 km, trees (49%) and water (23%) within 16 km, and trees (44%), water (26%) and grassland (20%) within 80 km.

3 km
26 m
16 km
96 m
80 km
149 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: La Teste-de-Buch 6.0 km · Cestas 33 km · Gradignan 39 km · Pessac 39 km · Saint-Médard-en-Jalles 40 km · Mérignac 41 km · Talence 42 km · Villenave-d'Ornon 43 km

France travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / E
230 V · 50 Hz
Prices
≈ 77% of US
price level, 2025
GDP per capita
$48,986
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1.3
per 100k, 2023
Road deaths
5.1
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 539
Religion
Roman Catholic 47%none 33%Muslim 4%Protestant 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 Gujan-Mestras (44.636°, -1.0681°, elevation 5 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).