Gorseinon weather in September

In September, Gorseinon sees average daytime highs of 17°C and overnight lows near 11°C, with 90 mm of rain across 12.6 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 18°C in the first days to 16°C by the end. The sky is clear or mostly clear about 13% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 24 min at the start of September to 11 h 24 min by month's end. Set against the rest of the year, September is Gorseinon's 5th-clearest and 9th-windiest month. For the whole year in context, see Gorseinon's year-round climate.

Daytime high
17°
4th warmest
Overnight low
11°
9th coldest
Rainfall
90 mm
12.6 wet days
Daylight
12 h 24 min
5:59 AM – 6:22 PM
Cloud cover
71%
5th clearest
Wind
15 km/h
9th windiest
Solar energy
3.21 kWh/m²
Travel score
4.8
out of 10

Gorseinon is district town in Swansea, Wales.

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 18°C in the first days to 16°C by the end.

A typical September day in Gorseinon reaches about 17°C in the afternoon and slips back to 11°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 19°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11812
21812
31811
41811
51811
61811
71811
81711
91711
101711
111711
121711
131711
141711
151711
161711
171711
181711
191710
201610
211610
221610
231610
241610
251610
261610
271610
281610
291510
301510

How September really feels in Gorseinon

Once humidity and wind are folded in, September averages 0 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
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Gorseinon 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 daysSnow daysDaylight (hours)Travel score
Jan / 12215.90.78.10.9
Feb / 92130.99.61.0
Mar / 8113.30.611.51.8
Apr12° / 7513.10.113.62.9
May15° / 8213.8015.44.0
Jun17° / 11°8513.9016.34.9
Jul19° / 13°9115.1015.95.3
Aug19° / 13°9914.8014.45.2
Sep17° / 11°9012.6012.44.8
Oct14° / 12715.7010.43.3
Nov10° / 12515.90.18.62.0
Dec / 13315.40.47.71.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 13% 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 71%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13070
23070
33070
43169
53169
63169
73169
83169
93268
103169
113169
123169
133070
143070
153070
163169
173070
183070
193070
202971
212872
222872
232773
242773
252575
262575
272575
282575
292575
302575

Chance of precipitation in September

Any precipitation

Gorseinon gets around 90 mm of rain over 12.6 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 43% and peaks near 50% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
139
238
338
438
539
639
739
840
940
1041
1141
1241
1342
1442
1542
1642
1742
1842
1943
2043
2143
2244
2345
2446
2547
2647
2748
2849
2950
3050

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 76% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
166304
267294
368284
469274
569274
670264
771254
872244
972244
1073234
1175223
1275223
1376213
1476213
1577212
1678202
1778202
1879201
1979201
2079201
2179201
2279201
2380200
2480200
2581190
2681190
2782180
2883170
2983170
3084160

Wind in September

Winds average 15 km/h in September.

Across September, daily wind ranges from about 14 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
114light breeze
214light breeze
314light breeze
414light breeze
514light breeze
614light breeze
714light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2215light breeze
2315light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2816light breeze
2916light breeze
3016light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 24 min at the start of September to 11 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 120 minutes over September. Sunrise moves from 5:34 AM to 6:22 AM, and sunset from 6:58 PM to 5:49 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.45:346:58
213.35:366:56
313.35:376:53
413.25:396:51
513.15:416:49
613.15:426:46
713.05:446:44
812.95:456:41
912.95:476:39
1012.85:496:37
1112.75:506:34
1212.75:526:32
1312.65:546:29
1412.55:556:27
1512.55:576:25
1612.45:596:22
1712.36:006:20
1812.36:026:17
1912.26:046:15
2012.16:056:13
2112.16:076:10
2212.06:096:08
2311.96:106:05
2411.86:126:03
2511.86:146:01
2611.76:165:58
2711.66:175:56
2811.66:195:53
2911.56:215:51
3011.46:225:49

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.21 kWh/m².

For context, solar energy here swings from a low near 0.65 kWh/m² to a high of 5.66 kWh/m² in June across the year — September's 3.21 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.9Moderate
23.8Moderate
33.8Moderate
43.7Moderate
53.7Moderate
63.7Moderate
73.6Moderate
83.6Moderate
93.5Moderate
103.5Moderate
113.5Moderate
123.4Moderate
133.4Moderate
143.3Moderate
153.3Moderate
163.2Moderate
173.2Moderate
183.1Moderate
193.1Moderate
203.0Moderate
213.0Moderate
222.9Moderate
232.9Moderate
242.8Moderate
252.7Moderate
262.7Moderate
272.6Moderate
282.6Moderate
292.5Moderate
302.5Moderate
Planning a trip in September

Is September a good time to visit Gorseinon?

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

4.8
Sightseeing
4th-best month of the year
1.0
Beach & pool
4th-best month of the year

September is a reasonable time to visit Gorseinon for sightseeing.

What to pack for Gorseinon in September

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

In September, Gorseinon sees daytime highs around 17°C and nights near 11°C. Worth packing: a warm layer and rain gear. About 13 days see rain.

a warm layerrain gear

Sea temperature near Gorseinon 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 at the nearest coast (about 13 km away) is warmest in August at about 18°C and coldest in February near 8°C.

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

5°10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan8Bracing
Feb8Bracing
Mar8Bracing
Apr9Bracing
May11Bracing
Jun14Bracing
Jul16Cool
Aug18Cool
Sep17Cool
Oct15Cool
Nov12Bracing
Dec10Bracing

UV index in Gorseinon in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Gorseinon peaks around August 13 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowAug 13UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May6High
Jun6High
Jul6High
Aug7High
Sep4Moderate
Oct2Moderate
Nov1Low
Dec1Low
Location & terrain

Where is Gorseinon?

Gorseinon sits at 51.7°N, 4.0°W, 23 m above sea level, in United Kingdom. The nearest listed city is Llanelli, 8.0 km away.

Topography around Gorseinon

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

Within 3 km, the terrain around Gorseinon has only modest variations in elevation — a maximum elevation change of 104 m around an average of 29 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 372 m; within 80 km, large variations in elevation — a maximum elevation change of 878 m.

The land around Gorseinon is covered by grassland (39%) and trees (34%) within 3 km, grassland (38%), trees (29%) and water (21%) within 16 km, and grassland (43%) and water (39%) within 80 km.

3 km
104 m
16 km
372 m
80 km
878 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Llanelli 8.0 km · Swansea 9.0 km · Clydach 10 km · Ammanford 14 km · Briton Ferry 16 km · Neath 16 km · Maesteg 27 km · Carmarthen 28 km

United Kingdom travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type D / G / M
230 V · 50 Hz
Prices
≈ 89% of US
price level, 2025
GDP per capita
$57,602
2025
Happiness
6.7 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1.1
per 100k, 2021
Road deaths
3.2
per 100k/yr, 2019
Income group
High
World Bank
Religion
Christian 60%none 26%Muslim 4%other 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 Gorseinon (51.6693°, -4.0416°, elevation 23 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).