Saint Peter Port weather in September

In September, Saint Peter Port sees average daytime highs of 17°C and overnight lows near 15°C, with 57 mm of rain across 9.4 wet days and about 12.4 hours of daylight. It is the 2nd-warmest and 7th-wettest month of the year here.

Day-to-day highs hold fairly steady near 17°C through the month. The sky is clear or mostly clear about 31% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 18 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Saint Peter Port's 4th-clearest and 7th-windiest month. For the whole year in context, see Saint Peter Port's year-round climate.

Daytime high: 17°; 2nd warmest
Overnight low: 15°; 11th coldest
Rainfall: 57 mm; 9.4 wet days
Daylight: 12 h 24 min; 5:54 AM – 6:15 PM
Cloud cover: 58%; 4th clearest
Wind: 26 km/h; 7th windiest
Solar energy: 3.76 kWh/m²
Travel score: 5.5; out of 10

Saint Peter Port is parish, port, and capital of Guernsey in the Channel Islands.

Density: 2,537/km²; people per km²

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

← August Saint Peter Port 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

Day-to-day highs hold fairly steady near 17°C through the month.

A typical September day in Saint Peter Port reaches about 17°C in the afternoon and slips back to 15°C overnight — a 1°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 18°C. Set against its neighbours, September runs on par with August and about 2°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)	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	17	16	16	16
Avg low (°C)	16	16	16	16	16	16	16	16	16	16	16	16	16	16	16	15	15	15	15	15	15	15	15	15	15	15	15	15	15	15

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

Saint Peter Port weather by month

How September compares with the rest of the year at a glance. September is the 2nd-warmest and 7th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	10° / 8°	98	15.7	8.4	1.8
Feb	9° / 7°	74	13.3	9.8	1.7
Mar	10° / 8°	58	11.5	11.5	2.0
Apr	11° / 9°	50	9.7	13.4	2.6
May	13° / 11°	45	7.9	15.1	3.6
Jun	15° / 13°	42	7.5	16	4.7
Jul	17° / 15°	36	6.9	15.6	5.7
Aug	17° / 16°	50	8.6	14.2	5.9
Sep	17° / 15°	57	9.4	12.4	5.5
Oct	15° / 14°	107	15	10.5	4.1
Nov	13° / 11°	121	17.7	8.9	2.8
Dec	11° / 9°	121	17	8	2.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 31% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 51%. Skies tend to cloud over as the month goes on.

	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 (%)	56	56	56	55	55	54	54	53	53	51	51	51	51	50	50	49	49	49	48	48	48	47	47	46	45	44	43	43	41	41
Cloudier (%)	44	44	44	45	45	46	46	47	47	49	49	49	49	50	50	51	51	51	52	52	52	53	53	54	55	56	57	57	59	59

	Clearer (%)	Cloudier (%)
1	56	44
2	56	44
3	56	44
4	55	45
5	55	45
6	54	46
7	54	46
8	53	47
9	53	47
10	51	49
11	51	49
12	51	49
13	51	49
14	50	50
15	50	50
16	49	51
17	49	51
18	49	51
19	48	52
20	48	52
21	48	52
22	47	53
23	47	53
24	46	54
25	45	55
26	44	56
27	43	57
28	43	57
29	41	59
30	41	59

Chance of precipitation in September

Any precipitation

Saint Peter Port gets around 57 mm of rain over 9.4 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 32% 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	28	28	29	29	29	30	31	31	32	33	34	35	36	37	38	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	28
12	28
13	29
14	29
15	29
16	30
17	31
18	31
19	32
20	33
21	34
22	35
23	36
24	37
25	38
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 50% 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 (%)	36	38	39	40	41	42	43	44	45	46	47	48	49	50	51	51	52	53	53	54	54	55	54	55	55	56	57	57	59	60
Comfortable (%)	48	47	46	45	44	43	42	41	40	40	39	38	38	38	38	38	38	38	38	38	38	38	39	39	39	39	38	38	37	36
Humid (%)	15	15	15	15	15	15	15	15	14	14	14	13	13	12	11	11	10	9	9	8	8	7	7	6	6	5	5	5	4	4

	Dry (%)	Comfortable (%)	Humid (%)
1	36	48	15
2	38	47	15
3	39	46	15
4	40	45	15
5	41	44	15
6	42	43	15
7	43	42	15
8	44	41	15
9	45	40	14
10	46	40	14
11	47	39	14
12	48	38	13
13	49	38	13
14	50	38	12
15	51	38	11
16	51	38	11
17	52	38	10
18	53	38	9
19	53	38	9
20	54	38	8
21	54	38	8
22	55	38	7
23	54	39	7
24	55	39	6
25	55	39	6
26	56	39	5
27	57	38	5
28	57	38	5
29	59	37	4
30	60	36	4

Wind in September

Winds average 26 km/h in September.

Across September, daily wind ranges from about 24 km/h on the calmest days to 28 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)	24	24	24	25	25	25	25	25	25	26	26	26	26	26	26	26	26	26	26	26	26	27	27	27	27	27	27	27	28	28
Feels	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy

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

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 18 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 108 minutes over September. Sunrise moves from 5:31 AM to 6:15 AM, and sunset from 6:49 PM to 5:44 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)	13.3	13.2	13.2	13.1	13.0	13.0	12.9	12.9	12.8	12.7	12.7	12.6	12.5	12.5	12.4	12.4	12.3	12.2	12.2	12.1	12.0	12.0	11.9	11.9	11.8	11.7	11.7	11.6	11.5	11.5
Sunrise (AM)	5:31	5:33	5:34	5:36	5:37	5:39	5:40	5:42	5:43	5:45	5:46	5:48	5:49	5:51	5:52	5:54	5:55	5:57	5:58	6:00	6:01	6:03	6:04	6:06	6:07	6:09	6:10	6:12	6:13	6:15
Sunset (PM)	6:49	6:46	6:44	6:42	6:40	6:38	6:35	6:33	6:31	6:29	6:27	6:24	6:22	6:20	6:18	6:15	6:13	6:11	6:09	6:06	6:04	6:02	6:00	5:57	5:55	5:53	5:51	5:48	5:46	5:44

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.3	5:31	6:49
2	13.2	5:33	6:46
3	13.2	5:34	6:44
4	13.1	5:36	6:42
5	13.0	5:37	6:40
6	13.0	5:39	6:38
7	12.9	5:40	6:35
8	12.9	5:42	6:33
9	12.8	5:43	6:31
10	12.7	5:45	6:29
11	12.7	5:46	6:27
12	12.6	5:48	6:24
13	12.5	5:49	6:22
14	12.5	5:51	6:20
15	12.4	5:52	6:18
16	12.4	5:54	6:15
17	12.3	5:55	6:13
18	12.2	5:57	6:11
19	12.2	5:58	6:09
20	12.1	6:00	6:06
21	12.0	6:01	6:04
22	12.0	6:03	6:02
23	11.9	6:04	6:00
24	11.9	6:06	5:57
25	11.8	6:07	5:55
26	11.7	6:09	5:53
27	11.7	6:10	5:51
28	11.6	6:12	5:48
29	11.5	6:13	5:46
30	11.5	6:15	5:44

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.76 kWh/m².

For context, solar energy here swings from a low near 0.8 kWh/m² to a high of 6.39 kWh/m² in June across the year — September's 3.76 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)	4.5	4.5	4.4	4.4	4.3	4.3	4.2	4.2	4.1	4.1	4.0	4.0	3.9	3.9	3.8	3.7	3.7	3.6	3.6	3.5	3.5	3.4	3.3	3.3	3.2	3.1	3.1	3.0	3.0	2.9
Level	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	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	4.5	Bright
2	4.5	Bright
3	4.4	Bright
4	4.4	Bright
5	4.3	Bright
6	4.3	Bright
7	4.2	Bright
8	4.2	Bright
9	4.1	Bright
10	4.1	Bright
11	4.0	Bright
12	4.0	Moderate
13	3.9	Moderate
14	3.9	Moderate
15	3.8	Moderate
16	3.7	Moderate
17	3.7	Moderate
18	3.6	Moderate
19	3.6	Moderate
20	3.5	Moderate
21	3.5	Moderate
22	3.4	Moderate
23	3.3	Moderate
24	3.3	Moderate
25	3.2	Moderate
26	3.1	Moderate
27	3.1	Moderate
28	3.0	Moderate
29	3.0	Moderate
30	2.9	Moderate

Planning a trip in September

Hazard calendar for Saint Peter Port

In seasonPeak

In September, Saint Peter Port sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

Saint Peter Port's rainy season runs September–March, when most of the year's rain falls.

Rainy season

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Is September a good time to visit Saint Peter Port?

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

5.5

Sightseeing

3rd-best month of the year

1.3

Beach & pool

2nd-best month of the year

September is a reasonable time to visit Saint Peter Port for sightseeing.

What to pack for Saint Peter Port in September

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

In September, Saint Peter Port sees daytime highs around 17°C and nights near 15°C. Worth packing: a warm layer, rain gear and a windbreaker. About 9 days see rain.

a warm layerrain geara windbreaker

Sea temperature near Saint Peter Port in September

The nearest coast averages about 17°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 September at about 17°C and coldest in March near 9°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)	10	10	9	10	12	14	16	17	17	16	14	12
Comfort	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Cool	Cool	Cool	Cool	Bracing	Bracing

	Sea temperature (°C)	Comfort
Jan	10	Bracing
Feb	10	Bracing
Mar	9	Bracing
Apr	10	Bracing
May	12	Bracing
Jun	14	Bracing
Jul	16	Cool
Aug	17	Cool
Sep	17	Cool
Oct	16	Cool
Nov	14	Bracing
Dec	12	Bracing

UV index in Saint Peter Port 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 Saint Peter Port peaks around August 12 at about 6 (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 6 months of the year.

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

Location & terrain

Where is Saint Peter Port?

Saint Peter Port sits at 49.5°N, 2.5°W, 10 m above sea level, in Guernsey. The nearest listed city is Saint Helier, 43 km away.

Topography around Saint Peter Port

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

Within 3 km, the terrain around Saint Peter Port has only modest variations in elevation — a maximum elevation change of 105 m around an average of 24 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 108 m; within 80 km, only modest variations in elevation — a maximum elevation change of 191 m.

The land around Saint Peter Port is covered by water (41%) and trees (25%) within 3 km, water (91%) within 16 km, and water (88%) within 80 km.

3 km

105 m

water 41%

16 km

108 m

water 91%

80 km

191 m

water 88%

treesgrasslandcroplandartificial surfaceswater

← August Saint Peter Port year-round climate October →Best places to visit in September

September weather nearby: Saint Helier 43 km · Octeville 67 km · Équeurdreville-Hainneville 67 km · Cherbourg 69 km · Tourlaville 73 km · Saint-Malo 98 km · Lannion 105 km · Saint-Brieuc 106 km

Guernsey travel facts

Power plugs: Type G; 230 V · 50 Hz

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 Peter Port (49.4598°, -2.5353°, elevation 10 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	17	16
2	17	16
3	17	16
4	17	16
5	17	16
6	17	16
7	17	16
8	17	16
9	17	16
10	17	16
11	17	16
12	17	16
13	17	16
14	17	16
15	17	16
16	17	15
17	17	15
18	17	15
19	17	15
20	17	15
21	17	15
22	17	15
23	17	15
24	17	15
25	17	15
26	17	15
27	17	15
28	16	15
29	16	15
30	16	15

	Clearer (%)	Cloudier (%)
1	56	44
2	56	44
3	56	44
4	55	45
5	55	45
6	54	46
7	54	46
8	53	47
9	53	47
10	51	49
11	51	49
12	51	49
13	51	49
14	50	50
15	50	50
16	49	51
17	49	51
18	49	51
19	48	52
20	48	52
21	48	52
22	47	53
23	47	53
24	46	54
25	45	55
26	44	56
27	43	57
28	43	57
29	41	59
30	41	59

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

	Dry (%)	Comfortable (%)	Humid (%)
1	36	48	15
2	38	47	15
3	39	46	15
4	40	45	15
5	41	44	15
6	42	43	15
7	43	42	15
8	44	41	15
9	45	40	14
10	46	40	14
11	47	39	14
12	48	38	13
13	49	38	13
14	50	38	12
15	51	38	11
16	51	38	11
17	52	38	10
18	53	38	9
19	53	38	9
20	54	38	8
21	54	38	8
22	55	38	7
23	54	39	7
24	55	39	6
25	55	39	6
26	56	39	5
27	57	38	5
28	57	38	5
29	59	37	4
30	60	36	4

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

	Clearer (%)	Cloudier (%)
1	56	44
2	56	44
3	56	44
4	55	45
5	55	45
6	54	46
7	54	46
8	53	47
9	53	47
10	51	49
11	51	49
12	51	49
13	51	49
14	50	50
15	50	50
16	49	51
17	49	51
18	49	51
19	48	52
20	48	52
21	48	52
22	47	53
23	47	53
24	46	54
25	45	55
26	44	56
27	43	57
28	43	57
29	41	59
30	41	59

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

	Dry (%)	Comfortable (%)	Humid (%)
1	36	48	15
2	38	47	15
3	39	46	15
4	40	45	15
5	41	44	15
6	42	43	15
7	43	42	15
8	44	41	15
9	45	40	14
10	46	40	14
11	47	39	14
12	48	38	13
13	49	38	13
14	50	38	12
15	51	38	11
16	51	38	11
17	52	38	10
18	53	38	9
19	53	38	9
20	54	38	8
21	54	38	8
22	55	38	7
23	54	39	7
24	55	39	6
25	55	39	6
26	56	39	5
27	57	38	5
28	57	38	5
29	59	37	4
30	60	36	4

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

	Clearer (%)	Cloudier (%)
1	56	44
2	56	44
3	56	44
4	55	45
5	55	45
6	54	46
7	54	46
8	53	47
9	53	47
10	51	49
11	51	49
12	51	49
13	51	49
14	50	50
15	50	50
16	49	51
17	49	51
18	49	51
19	48	52
20	48	52
21	48	52
22	47	53
23	47	53
24	46	54
25	45	55
26	44	56
27	43	57
28	43	57
29	41	59
30	41	59

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

	Dry (%)	Comfortable (%)	Humid (%)
1	36	48	15
2	38	47	15
3	39	46	15
4	40	45	15
5	41	44	15
6	42	43	15
7	43	42	15
8	44	41	15
9	45	40	14
10	46	40	14
11	47	39	14
12	48	38	13
13	49	38	13
14	50	38	12
15	51	38	11
16	51	38	11
17	52	38	10
18	53	38	9
19	53	38	9
20	54	38	8
21	54	38	8
22	55	38	7
23	54	39	7
24	55	39	6
25	55	39	6
26	56	39	5
27	57	38	5
28	57	38	5
29	59	37	4
30	60	36	4