Saint-Louis weather in September

In September, Saint-Louis sees average daytime highs of 30°C and overnight lows near 27°C, with 52 mm of rain across 7.2 wet days and about 12.1 hours of daylight. It is the 2nd-warmest and 2nd-wettest month of the year here.

Day-to-day highs hold fairly steady near 30°C through the month. The sky is clear or mostly clear about 42% of the time in September, and the air most often feels miserable.

Daylight stretches from about 12 h 18 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Saint-Louis's 11th-clearest and 12th-windiest month. For the whole year in context, see Saint-Louis's year-round climate.

Daytime high
30°
2nd warmest
Overnight low
27°
12th coldest
Rainfall
52 mm
7.2 wet days
Daylight
12 h 06 min
6:58 AM – 7:03 PM
Cloud cover
52%
11th clearest
Wind
16 km/h
12th windiest
Solar energy
6.09 kWh/m²
Travel score
5.6
out of 10

Saint-Louis is city and regional capital in Senegal.

Founded
1659

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 30°C through the month.

A typical September day in Saint-Louis reaches about 30°C in the afternoon and slips back to 27°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 31°C. Set against its neighbours, September runs about 1°C warmer than August and on par with October.

25°28°30°33°35°151015202530
Avg high (°C)Avg low (°C)
12926
22926
32926
42927
52927
62927
72927
82927
92927
102927
112927
123027
133027
143027
153027
163027
173027
183027
193027
203027
213027
223027
233027
243027
253027
263027
273027
283027
293027
303027

How September really feels in Saint-Louis

Once humidity and wind are folded in, September averages 30 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
30
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Saint-Louis weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan25° / 19°30.211.28.7
Feb25° / 19°10.211.58.8
Mar25° / 20°0011.99.1
Apr25° / 20°0012.39.2
May25° / 21°0012.79.1
Jun27° / 23°10.312.98.7
Jul28° / 25°11212.97.6
Aug29° / 26°577.812.55.9
Sep30° / 27°527.212.15.6
Oct30° / 26°132.111.66.1
Nov29° / 24°00.111.36.8
Dec27° / 21°20.311.18.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 42% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 42%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14852
24753
34852
45050
55050
65149
75248
85347
95446
105446
115545
125644
135644
145743
155743
165941
175941
185941
196040
206139
216139
226238
236337
246337
256436
266634
276733
286832
296931
307030

Chance of precipitation in September

Any precipitation

Saint-Louis gets around 52 mm of rain over 7.2 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 23% and peaks near 31% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
131
231
331
431
530
629
729
828
927
1027
1126
1226
1325
1424
1524
1623
1723
1822
1922
2021
2121
2220
2319
2419
2518
2617
2716
2815
2915
3014

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the miserable band about 76% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
102278
202179
302179
402080
502080
601981
701981
801981
901981
1012079
1112079
1212079
1312079
1412178
1512178
1612178
1712277
1812277
1912376
2012376
2112475
2222573
2322573
2422672
2522771
2622870
2722969
2823068
2933166
3033265

Wind in September

Winds average 16 km/h in September, the calmest month.

Across September, daily wind ranges from about 16 km/h on the calmest days to 16 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
116light breeze
216light breeze
316light breeze
416light breeze
516light breeze
616light breeze
716light breeze
816light breeze
916light breeze
1016light breeze
1116light breeze
1216light breeze
1316light breeze
1416light breeze
1516light breeze
1616light breeze
1716light breeze
1816light breeze
1916light breeze
2016light breeze
2116light breeze
2216light breeze
2316light breeze
2416light breeze
2516light breeze
2616light breeze
2716light breeze
2816light breeze
2916light breeze
3016light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 18 min at the start of September to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 24 minutes over September. Sunrise moves from 6:56 AM to 6:59 AM, and sunset from 7:15 PM to 6:51 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.36:567:15
212.36:567:14
312.36:567:14
412.36:577:13
512.36:577:12
612.26:577:11
712.26:577:10
812.26:577:10
912.26:577:09
1012.26:577:08
1112.26:577:07
1212.26:577:06
1312.16:577:05
1412.16:577:05
1512.16:587:04
1612.16:587:03
1712.16:587:02
1812.16:587:01
1912.06:587:00
2012.06:587:00
2112.06:586:59
2212.06:586:58
2312.06:586:57
2412.06:586:56
2511.96:586:55
2611.96:596:55
2711.96:596:54
2811.96:596:53
2911.96:596:52
3011.96:596:51

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.09 kWh/m².

For context, solar energy here swings from a low near 5 kWh/m² to a high of 7.37 kWh/m² in May across the year — September's 6.09 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.9Bright
25.9Bright
35.9Bright
45.9Bright
55.9Bright
66.0Bright
76.0Bright
86.0Bright
96.0Intense
106.0Intense
116.0Intense
126.1Intense
136.1Intense
146.1Intense
156.1Intense
166.1Intense
176.1Intense
186.2Intense
196.2Intense
206.2Intense
216.2Intense
226.2Intense
236.2Intense
246.2Intense
256.2Intense
266.2Intense
276.2Intense
286.2Intense
296.2Intense
306.2Intense
Planning a trip in September

Hazard calendar for Saint-Louis

In seasonPeak

In September, Saint-Louis sits inside its atlantic hurricane and dust season. The full year is below, with each hazard's peak months called out.

Saint-Louis sits in the Atlantic hurricane belt; the season peaks August–October.

Saint-Louis sees dust haze year-round, heaviest in June.

Atlantic hurricane
Dust
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Saint-Louis?

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

5.6
Sightseeing
12th-best month of the year
7.5
Beach & pool
11th-best month of the year

September is a reasonable time to visit Saint-Louis for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Saint-Louis in September

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

In September, Saint-Louis sees daytime highs around 30°C and nights near 27°C. Pack light clothes and sun protection. About 7 days see rain.

light clothessun protection

Sea temperature near Saint-Louis in September

The nearest coast averages about 28°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 19 km away) is warmest in September at about 28°C and coldest in February near 19°C.

It's comfortable for a long swim from May 3 to Jan 11 — about 8.4 months when the water holds above 20°C.

20°25°30°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan20Cool
Feb19Cool
Mar19Cool
Apr19Cool
May21Refreshing
Jun24Refreshing
Jul26Warm
Aug28Warm
Sep28Tropical
Oct28Warm
Nov25Warm
Dec22Refreshing

UV index in Saint-Louis in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 11 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Saint-Louis peaks around March 18 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 7 (very high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highExtremeVery highMar 18UV 12Dec 15UV 7
UV index (midday)Level
Jan8Very high
Feb11Extreme
Mar13Extreme
Apr11Extreme
May12Extreme
Jun10Extreme
Jul10Very high
Aug11Extreme
Sep11Extreme
Oct9Very high
Nov8Very high
Dec7High

Air quality in Saint-Louis in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Saint-Louis is worst in January — around 99 µg/m³ PM2.5 (unhealthy), about 3.3× the cleanest month (August, 30 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0306090120JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyPoorPoorModeratePoorUnhealthyJan 2199 µg/m³Aug 2031 µg/m³
PM2.5 (µg/m³)Level
Jan99Unhealthy
Feb97Unhealthy
Mar70Unhealthy
Apr50Poor
May46Poor
Jun61Unhealthy
Jul42Poor
Aug30Moderate
Sep35Moderate
Oct51Poor
Nov54Poor
Dec90Unhealthy
Location & terrain

Where is Saint-Louis?

Saint-Louis sits at 16.0°N, 16.5°W, 8 m above sea level, in Senegal. The nearest listed city is Louga, 53 km away.

LougaKébémerRossoRichard-TollMékhéMboroDaganaTivaouane

Topography around Saint-Louis

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

Within 3 km, the terrain around Saint-Louis has only modest variations in elevation — a maximum elevation change of 9 m around an average of 1 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 26 m; within 80 km, only modest variations in elevation — a maximum elevation change of 57 m.

The land around Saint-Louis is covered by water (34%), artificial surfaces (27%) and wetland (22%) within 3 km, water (47%) and grassland (26%) within 16 km, and grassland (39%) and water (35%) within 80 km.

3 km
9 m
16 km
26 m
80 km
57 m
shrubsgrasslandcroplandartificial surfacesbare terrainwaterwetlandmangroves
September weather nearby: Louga 53 km · Kébémer 73 km · Rosso 92 km · Richard-Toll 98 km · Mékhé 102 km · Mboro 106 km · Dagana 108 km · Tivaouane 124 km

Senegal travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / D / E / K
230 V · 50 Hz
Prices
≈ 36% of US
price level, 2025
GDP per capita
$1,955
2025
Happiness
4.8 / 10
World Happiness, 2025
Safe drinking water
27%
of population, 2024
Homicide rate
0.3
per 100k, 2015
Road deaths
23.5
per 100k/yr, 2019
Income group
Lower middle
World Bank
English
Very low
EF EPI 442
Religion
Muslim 97%Christian 3%

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 Saint-Louis (16.0179°, -16.4896°, elevation 8 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).