Brest weather in September

In September, Brest sees average daytime highs of 18°C and overnight lows near 13°C, with 52 mm of rain across 9.6 wet days and about 12.4 hours of daylight. It is the 3rd-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 19°C in the first days to 17°C by the end. The sky is clear or mostly clear about 24% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 12 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Brest's 1st-clearest and 9th-windiest month. For the whole year in context, see Brest's year-round climate.

Daytime high: 18°; 3rd warmest
Overnight low: 13°; 10th coldest
Rainfall: 52 mm; 9.6 wet days
Daylight: 12 h 18 min; 7:02 AM – 7:23 PM
Cloud cover: 61%; 1st clearest
Wind: 17 km/h; 9th windiest
Solar energy: 3.93 kWh/m²
Travel score: 5.8; out of 10

Brest is port city in the Finistère department, Brittany, France.

Air quality: Good; PM2.5 7.5 µg/m³ · 2019
Density: 2,927/km²; people per km²

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

← August Brest year-round climate October →Best places to visit in September

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 19°C in the first days to 17°C by the end.

A typical September day in Brest reaches about 18°C in the afternoon and slips back to 13°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 21°C. Set against its neighbours, September runs about 1°C cooler than August and about 3°C warmer than October.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°C)	19	19	19	19	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	17	17	17	17	17	17	17	17	17	17	17
Avg low (°C)	14	14	14	14	14	14	14	14	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	12	12	12

	Avg high (°C)	Avg low (°C)
1	19	14
2	19	14
3	19	14
4	19	14
5	18	14
6	18	14
7	18	14
8	18	14
9	18	13
10	18	13
11	18	13
12	18	13
13	18	13
14	18	13
15	18	13
16	18	13
17	18	13
18	18	13
19	18	13
20	17	13
21	17	13
22	17	13
23	17	13
24	17	13
25	17	13
26	17	13
27	17	13
28	17	12
29	17	12
30	17	12

Brest 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.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	10° / 7°	99	15.3	8.6	1.8
Feb	10° / 6°	79	13.3	9.9	1.8
Mar	11° / 7°	64	12.6	11.6	2.5
Apr	13° / 8°	66	11.9	13.4	3.2
May	15° / 10°	59	10.6	15	4.4
Jun	17° / 13°	47	9.7	15.8	5.5
Jul	19° / 14°	45	10.1	15.5	6.1
Aug	19° / 14°	53	10	14.1	6.1
Sep	18° / 13°	52	9.6	12.4	5.8
Oct	15° / 11°	92	14.1	10.6	4.1
Nov	12° / 9°	96	14.9	9	2.9
Dec	11° / 7°	106	15.3	8.2	2.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 24% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 21% of September, with mostly cloudy or overcast conditions the remaining 55%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	47	47	47	48	48	48	47	46	47	47	46	45	45	45	45	45	45	44	45	45	44	44	44	43	43	43	42	41	41	40
Cloudier (%)	53	53	53	52	52	52	53	54	53	53	54	55	55	55	55	55	55	56	55	55	56	56	56	57	57	57	58	59	59	60

	Clearer (%)	Cloudier (%)
1	47	53
2	47	53
3	47	53
4	48	52
5	48	52
6	48	52
7	47	53
8	46	54
9	47	53
10	47	53
11	46	54
12	45	55
13	45	55
14	45	55
15	45	55
16	45	55
17	45	55
18	44	56
19	45	55
20	45	55
21	44	56
22	44	56
23	44	56
24	43	57
25	43	57
26	43	57
27	42	58
28	41	59
29	41	59
30	40	60

Chance of precipitation in September

Any precipitation

Brest gets around 52 mm of rain over 9.6 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 43% on the wettest days. The odds climb toward the end of the month.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	26	26	26	26	26	26	27	27	28	28	29	30	30	31	31	32	33	33	34	35	35	36	37	38	39	40	41	42	43	43

	Rain chance (%)
1	26
2	26
3	26
4	26
5	26
6	26
7	27
8	27
9	28
10	28
11	29
12	30
13	30
14	31
15	31
16	32
17	33
18	33
19	34
20	35
21	35
22	36
23	37
24	38
25	39
26	40
27	41
28	42
29	43
30	43

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 56% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Dry (%)	41	42	44	45	46	48	49	51	52	53	54	55	56	57	58	59	59	60	60	61	61	61	62	62	62	62	62	64	65	65
Comfortable (%)	49	48	47	46	44	43	42	40	39	38	37	36	36	35	34	34	34	34	34	34	34	34	34	34	34	34	34	33	32	32
Humid (%)	10	9	9	9	9	9	9	9	9	9	9	9	8	8	8	7	7	6	6	5	5	5	4	4	4	4	4	3	3	3

	Dry (%)	Comfortable (%)	Humid (%)
1	41	49	10
2	42	48	9
3	44	47	9
4	45	46	9
5	46	44	9
6	48	43	9
7	49	42	9
8	51	40	9
9	52	39	9
10	53	38	9
11	54	37	9
12	55	36	9
13	56	36	8
14	57	35	8
15	58	34	8
16	59	34	7
17	59	34	7
18	60	34	6
19	60	34	6
20	61	34	5
21	61	34	5
22	61	34	5
23	62	34	4
24	62	34	4
25	62	34	4
26	62	34	4
27	62	34	4
28	64	33	3
29	65	32	3
30	65	32	3

Wind in September

Winds average 17 km/h in September.

Across September, daily wind ranges from about 17 km/h on the calmest days to 19 km/h at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (km/h)	17	17	17	17	17	17	17	17	17	17	17	17	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	18	19	19
Feels	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze

	Wind speed (km/h)	Feels
1	17	light breeze
2	17	light breeze
3	17	light breeze
4	17	light breeze
5	17	light breeze
6	17	light breeze
7	17	light breeze
8	17	light breeze
9	17	light breeze
10	17	light breeze
11	17	light breeze
12	17	light breeze
13	18	light breeze
14	18	light breeze
15	18	light breeze
16	18	light breeze
17	18	light breeze
18	18	light breeze
19	18	light breeze
20	18	light breeze
21	18	light breeze
22	18	light breeze
23	18	light breeze
24	18	light breeze
25	18	light breeze
26	18	light breeze
27	18	light breeze
28	18	light breeze
29	19	light breeze
30	19	light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 12 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 102 minutes over September. Sunrise moves from 6:40 AM to 7:22 AM, and sunset from 7:55 PM to 6:52 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	13.2	13.2	13.1	13.1	13.0	12.9	12.9	12.8	12.8	12.7	12.6	12.6	12.5	12.5	12.4	12.3	12.3	12.2	12.2	12.1	12.0	12.0	11.9	11.9	11.8	11.7	11.7	11.6	11.6	11.5
Sunrise (AM)	6:40	6:42	6:43	6:45	6:46	6:47	6:49	6:50	6:52	6:53	6:55	6:56	6:58	6:59	7:00	7:02	7:03	7:05	7:06	7:08	7:09	7:11	7:12	7:13	7:15	7:16	7:18	7:19	7:21	7:22
Sunset (PM)	7:55	7:53	7:51	7:49	7:47	7:44	7:42	7:40	7:38	7:36	7:34	7:31	7:29	7:27	7:25	7:23	7:21	7:18	7:16	7:14	7:12	7:10	7:07	7:05	7:03	7:01	6:59	6:57	6:54	6:52

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.2	6:40	7:55
2	13.2	6:42	7:53
3	13.1	6:43	7:51
4	13.1	6:45	7:49
5	13.0	6:46	7:47
6	12.9	6:47	7:44
7	12.9	6:49	7:42
8	12.8	6:50	7:40
9	12.8	6:52	7:38
10	12.7	6:53	7:36
11	12.6	6:55	7:34
12	12.6	6:56	7:31
13	12.5	6:58	7:29
14	12.5	6:59	7:27
15	12.4	7:00	7:25
16	12.3	7:02	7:23
17	12.3	7:03	7:21
18	12.2	7:05	7:18
19	12.2	7:06	7:16
20	12.1	7:08	7:14
21	12.0	7:09	7:12
22	12.0	7:11	7:10
23	11.9	7:12	7:07
24	11.9	7:13	7:05
25	11.8	7:15	7:03
26	11.7	7:16	7:01
27	11.7	7:18	6:59
28	11.6	7:19	6:57
29	11.6	7:21	6:54
30	11.5	7:22	6:52

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.93 kWh/m².

For context, solar energy here swings from a low near 0.89 kWh/m² to a high of 6.38 kWh/m² in June across the year — September's 3.93 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	4.6	4.6	4.5	4.5	4.4	4.4	4.3	4.3	4.3	4.2	4.2	4.1	4.1	4.0	4.0	3.9	3.9	3.8	3.8	3.7	3.6	3.6	3.5	3.5	3.4	3.3	3.3	3.2	3.2	3.1
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	4.6	Bright
2	4.6	Bright
3	4.5	Bright
4	4.5	Bright
5	4.4	Bright
6	4.4	Bright
7	4.3	Bright
8	4.3	Bright
9	4.3	Bright
10	4.2	Bright
11	4.2	Bright
12	4.1	Bright
13	4.1	Bright
14	4.0	Bright
15	4.0	Moderate
16	3.9	Moderate
17	3.9	Moderate
18	3.8	Moderate
19	3.8	Moderate
20	3.7	Moderate
21	3.6	Moderate
22	3.6	Moderate
23	3.5	Moderate
24	3.5	Moderate
25	3.4	Moderate
26	3.3	Moderate
27	3.3	Moderate
28	3.2	Moderate
29	3.2	Moderate
30	3.1	Moderate

Planning a trip in September

Is September a good time to visit Brest?

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

5.8

Sightseeing

3rd-best month of the year

1.8

Beach & pool

3rd-best month of the year

September is a reasonable time to visit Brest for sightseeing.

What to pack for Brest in September

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

In September, Brest sees daytime highs around 18°C and nights near 13°C. Worth packing: rain gear. About 10 days see rain.

rain gear

Sea temperature near Brest in September

The nearest coast averages about 15°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 16°C and coldest in February near 10°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Sea temperature (°C)	11	10	10	11	13	14	15	16	15	15	14	12
Comfort	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Cool	Cool	Cool	Bracing	Bracing	Bracing

	Sea temperature (°C)	Comfort
Jan	11	Bracing
Feb	10	Bracing
Mar	10	Bracing
Apr	11	Bracing
May	13	Bracing
Jun	14	Bracing
Jul	15	Cool
Aug	16	Cool
Sep	15	Cool
Oct	15	Bracing
Nov	14	Bracing
Dec	12	Bracing

UV index in Brest 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 Brest peaks around August 14 at about 7 (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 7 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	1	1	3	5	6	7	6	7	5	3	1	1
Level	Low	Low	Moderate	Moderate	High	High	High	High	Moderate	Moderate	Low	Low

	UV index (midday)	Level
Jan	1	Low
Feb	1	Low
Mar	3	Moderate
Apr	5	Moderate
May	6	High
Jun	7	High
Jul	6	High
Aug	7	High
Sep	5	Moderate
Oct	3	Moderate
Nov	1	Low
Dec	1	Low

Location & terrain

Where is Brest?

Brest sits at 48.4°N, 4.5°W, 49 m above sea level, in France. The nearest listed city is Landerneau, 19 km away.

Topography around Brest

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

Within 3 km, the terrain around Brest has only modest variations in elevation — a maximum elevation change of 109 m around an average of 39 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 182 m; within 80 km, significant variations in elevation — a maximum elevation change of 384 m.

The land around Brest is covered by artificial surfaces (46%), water (28%) and trees (22%) within 3 km, trees (27%), water (25%) and cropland (21%) within 16 km, and water (56%) within 80 km.

3 km

109 m

artificial surfaces 46%

16 km

182 m

trees 27%

80 km

384 m

water 56%

treesgrasslandcroplandartificial surfaceswater

← August Brest year-round climate October →Best places to visit in September

September weather nearby: Landerneau 19 km · Douarnenez 35 km · Quimper 52 km · Morlaix 53 km · Concarneau 71 km · Lannion 85 km · Ploemeur 107 km · Lorient 109 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

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 Brest (48.3903°, -4.4863°, elevation 49 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).

	Avg high (°C)	Avg low (°C)
1	19	14
2	19	14
3	19	14
4	19	14
5	18	14
6	18	14
7	18	14
8	18	14
9	18	13
10	18	13
11	18	13
12	18	13
13	18	13
14	18	13
15	18	13
16	18	13
17	18	13
18	18	13
19	18	13
20	17	13
21	17	13
22	17	13
23	17	13
24	17	13
25	17	13
26	17	13
27	17	13
28	17	12
29	17	12
30	17	12

	Clearer (%)	Cloudier (%)
1	47	53
2	47	53
3	47	53
4	48	52
5	48	52
6	48	52
7	47	53
8	46	54
9	47	53
10	47	53
11	46	54
12	45	55
13	45	55
14	45	55
15	45	55
16	45	55
17	45	55
18	44	56
19	45	55
20	45	55
21	44	56
22	44	56
23	44	56
24	43	57
25	43	57
26	43	57
27	42	58
28	41	59
29	41	59
30	40	60

	Rain chance (%)
1	26
2	26
3	26
4	26
5	26
6	26
7	27
8	27
9	28
10	28
11	29
12	30
13	30
14	31
15	31
16	32
17	33
18	33
19	34
20	35
21	35
22	36
23	37
24	38
25	39
26	40
27	41
28	42
29	43
30	43

	Dry (%)	Comfortable (%)	Humid (%)
1	41	49	10
2	42	48	9
3	44	47	9
4	45	46	9
5	46	44	9
6	48	43	9
7	49	42	9
8	51	40	9
9	52	39	9
10	53	38	9
11	54	37	9
12	55	36	9
13	56	36	8
14	57	35	8
15	58	34	8
16	59	34	7
17	59	34	7
18	60	34	6
19	60	34	6
20	61	34	5
21	61	34	5
22	61	34	5
23	62	34	4
24	62	34	4
25	62	34	4
26	62	34	4
27	62	34	4
28	64	33	3
29	65	32	3
30	65	32	3

	Avg high (°C)	Avg low (°C)
1	19	14
2	19	14
3	19	14
4	19	14
5	18	14
6	18	14
7	18	14
8	18	14
9	18	13
10	18	13
11	18	13
12	18	13
13	18	13
14	18	13
15	18	13
16	18	13
17	18	13
18	18	13
19	18	13
20	17	13
21	17	13
22	17	13
23	17	13
24	17	13
25	17	13
26	17	13
27	17	13
28	17	12
29	17	12
30	17	12

	Clearer (%)	Cloudier (%)
1	47	53
2	47	53
3	47	53
4	48	52
5	48	52
6	48	52
7	47	53
8	46	54
9	47	53
10	47	53
11	46	54
12	45	55
13	45	55
14	45	55
15	45	55
16	45	55
17	45	55
18	44	56
19	45	55
20	45	55
21	44	56
22	44	56
23	44	56
24	43	57
25	43	57
26	43	57
27	42	58
28	41	59
29	41	59
30	40	60

	Rain chance (%)
1	26
2	26
3	26
4	26
5	26
6	26
7	27
8	27
9	28
10	28
11	29
12	30
13	30
14	31
15	31
16	32
17	33
18	33
19	34
20	35
21	35
22	36
23	37
24	38
25	39
26	40
27	41
28	42
29	43
30	43

	Dry (%)	Comfortable (%)	Humid (%)
1	41	49	10
2	42	48	9
3	44	47	9
4	45	46	9
5	46	44	9
6	48	43	9
7	49	42	9
8	51	40	9
9	52	39	9
10	53	38	9
11	54	37	9
12	55	36	9
13	56	36	8
14	57	35	8
15	58	34	8
16	59	34	7
17	59	34	7
18	60	34	6
19	60	34	6
20	61	34	5
21	61	34	5
22	61	34	5
23	62	34	4
24	62	34	4
25	62	34	4
26	62	34	4
27	62	34	4
28	64	33	3
29	65	32	3
30	65	32	3

	Avg high (°C)	Avg low (°C)
1	19	14
2	19	14
3	19	14
4	19	14
5	18	14
6	18	14
7	18	14
8	18	14
9	18	13
10	18	13
11	18	13
12	18	13
13	18	13
14	18	13
15	18	13
16	18	13
17	18	13
18	18	13
19	18	13
20	17	13
21	17	13
22	17	13
23	17	13
24	17	13
25	17	13
26	17	13
27	17	13
28	17	12
29	17	12
30	17	12

	Clearer (%)	Cloudier (%)
1	47	53
2	47	53
3	47	53
4	48	52
5	48	52
6	48	52
7	47	53
8	46	54
9	47	53
10	47	53
11	46	54
12	45	55
13	45	55
14	45	55
15	45	55
16	45	55
17	45	55
18	44	56
19	45	55
20	45	55
21	44	56
22	44	56
23	44	56
24	43	57
25	43	57
26	43	57
27	42	58
28	41	59
29	41	59
30	40	60

	Rain chance (%)
1	26
2	26
3	26
4	26
5	26
6	26
7	27
8	27
9	28
10	28
11	29
12	30
13	30
14	31
15	31
16	32
17	33
18	33
19	34
20	35
21	35
22	36
23	37
24	38
25	39
26	40
27	41
28	42
29	43
30	43

	Dry (%)	Comfortable (%)	Humid (%)
1	41	49	10
2	42	48	9
3	44	47	9
4	45	46	9
5	46	44	9
6	48	43	9
7	49	42	9
8	51	40	9
9	52	39	9
10	53	38	9
11	54	37	9
12	55	36	9
13	56	36	8
14	57	35	8
15	58	34	8
16	59	34	7
17	59	34	7
18	60	34	6
19	60	34	6
20	61	34	5
21	61	34	5
22	61	34	5
23	62	34	4
24	62	34	4
25	62	34	4
26	62	34	4
27	62	34	4
28	64	33	3
29	65	32	3
30	65	32	3