Mont-de-Marsan weather in September

In September, Mont-de-Marsan sees average daytime highs of 25°C and overnight lows near 14°C, with 50 mm of rain across 8.3 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 11th-wettest month of the year here.

Highs ease over the month, from about 27°C in the first days to 23°C by the end. The sky is clear or mostly clear about 35% of the time in September, and the air most often feels dry.

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 Mont-de-Marsan's 2nd-clearest and 10th-windiest month. For the whole year in context, see Mont-de-Marsan's year-round climate.

Daytime high
25°
4th warmest
Overnight low
14°
9th coldest
Rainfall
50 mm
8.3 wet days
Daylight
12 h 18 min
6:47 AM – 7:05 PM
Cloud cover
53%
2nd clearest
Wind
8 km/h
10th windiest
Solar energy
4.24 kWh/m²
Travel score
7.0
out of 10
Air quality
Good
PM2.5 7.6 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 27°C in the first days to 23°C by the end.

A typical September day in Mont-de-Marsan reaches about 25°C in the afternoon and slips back to 14°C overnight — a 12°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 31°C. Set against its neighbours, September runs about 3°C cooler than August and about 5°C warmer than October.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
12815
22715
32715
42715
52715
62714
72714
82714
92614
102614
112614
122614
132614
142614
152514
162513
172513
182513
192513
202513
212413
222413
232413
242413
252413
262412
272412
282312
292312
302312

Mont-de-Marsan weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan11° / 66119.12.6
Feb13° / 529.510.23.4
Mar16° / 5610.711.65.1
Apr19° / 7412.213.25.7
May22° / 12°7211.914.56.3
Jun26° / 15°599.215.26.7
Jul29° / 16°457.814.96.2
Aug29° / 16°517.713.86.1
Sep25° / 14°508.312.37.0
Oct21° / 11°6210.210.86.3
Nov15° / 7411.59.54.2
Dec12° / 68118.82.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% 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 48%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15644
25743
35743
45743
55743
65644
75644
85545
95545
105545
115446
125446
135347
145347
155347
165248
175149
185149
195149
205149
215050
225050
235050
245050
254852
264852
274753
284852
294654
304654

Chance of precipitation in September

Any precipitation

Mont-de-Marsan gets around 50 mm of rain over 8.3 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 29% and peaks near 32% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
123
224
324
425
525
626
726
827
928
1029
1129
1230
1330
1430
1531
1631
1730
1830
1930
2030
2130
2230
2330
2430
2530
2631
2731
2831
2932
3032

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 47% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
13627289
23828278
33928267
44029247
54130236
64230235
74231225
84332214
94333204
104333204
114434193
124434193
134435192
144535182
154535182
164635171
174735171
184835161
194935151
205035150
215135140
225135140
235235130
245334130
255334130
265334130
275433130
285632120
295632120
305731120

Wind in September

Winds average 8 km/h in September.

Across September, daily wind ranges from about 8 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm

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 6:30 AM to 7:04 AM, and sunset from 7:34 PM to 6:39 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.16:307:34
213.06:317:32
313.06:327:30
412.96:337:28
512.96:357:26
612.86:367:24
712.86:377:22
812.76:387:21
912.76:397:19
1012.66:407:17
1112.66:427:15
1212.56:437:13
1312.56:447:11
1412.46:457:09
1512.36:467:07
1612.36:477:05
1712.26:497:03
1812.26:507:01
1912.16:516:59
2012.16:526:58
2112.06:536:56
2212.06:546:54
2311.96:566:52
2411.96:576:50
2511.86:586:48
2611.86:596:46
2711.77:006:44
2811.77:026:42
2911.67:036:40
3011.67:046:39

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.24 kWh/m².

For context, solar energy here swings from a low near 1.32 kWh/m² to a high of 6.06 kWh/m² in June across the year — September's 4.24 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.9Bright
34.8Bright
44.8Bright
54.7Bright
64.7Bright
74.6Bright
84.6Bright
94.5Bright
104.5Bright
114.4Bright
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 Mont-de-Marsan?

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

7.0
Sightseeing
1st-best month of the year
6.4
Beach & pool
4th-best month of the year

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

What to pack for Mont-de-Marsan in September

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

In September, Mont-de-Marsan sees daytime highs around 25°C and nights near 14°C. Worth packing: light clothes and rain gear. About 8 days see rain.

light clothesrain gear

Sea temperature near Mont-de-Marsan in September

The nearest coast averages about 21°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 70 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 3 to Sep 23 — about 2.7 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb12Bracing
Mar12Bracing
Apr14Bracing
May16Cool
Jun19Cool
Jul21Refreshing
Aug22Refreshing
Sep21Refreshing
Oct18Cool
Nov16Cool
Dec14Bracing

UV index in Mont-de-Marsan 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 Mont-de-Marsan peaks around July 17 at about 8 (very high) — sunscreen, a hat and midday shade are essential. 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 highHighModerateLowJul 17UV 8Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr6High
May6High
Jun7Very high
Jul8Very high
Aug8Very high
Sep5Moderate
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Mont-de-Marsan?

Mont-de-Marsan sits at 43.9°N, 0.5°W, 51 m above sea level, in France. The nearest listed city is Dax, 49 km away.

Topography around Mont-de-Marsan

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Mont-de-Marsan.

Within 3 km, the terrain around Mont-de-Marsan has only modest variations in elevation — a maximum elevation change of 73 m around an average of 61 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 128 m; within 80 km, large variations in elevation — a maximum elevation change of 637 m.

The land around Mont-de-Marsan is covered by trees (42%) and artificial surfaces (41%) within 3 km, trees (58%) and cropland (20%) within 16 km, and trees (49%), cropland (25%) and grassland (21%) within 80 km.

3 km
73 m
16 km
128 m
80 km
637 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Dax 49 km · Pau 65 km · Tarbes 86 km · Marmande 86 km · Bayonne 90 km · Auch 91 km · Anglet 93 km · Gujan-Mestras 95 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 Mont-de-Marsan (43.8902°, -0.4971°, elevation 51 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).