Llanfairpwllgwyngyll weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Poor
Best time to visit: April – August
What is the weather like in Llanfairpwllgwyngyll in September?
In September, Llanfairpwllgwyngyll is mild: daytime highs average 16 °C, and nights cool down to about 12 °C. The sea averages 15.6 °C – swimming is only for the hardy. Expect around 5 hours of sunshine a day. Rain is frequent, with about 13 rainy days and 83 mm in total. All in all, September is not an ideal month for a holiday in Llanfairpwllgwyngyll.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 17 | 14 | 5 |
| Day | 18° | 16° | 14° |
| Night | 13° | 12° | 10° |
| Sea | 16° | 16° | 14° |
| Sun | 6 h | 5 h | 4 h |
| Rain days | 14 | 13 | 16 |
More details for September
- Daylight
- 12 h 47 min06:49 – 19:36
- UV index
- 3 · moderateclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 25 km/haverage daily peakAll months
- Cloud cover
- 71 %on averageAll months
- Hot days
- 0 days30 °C or more
- Time zone
- UTC+1Europe/London
How the score comes together
- Temperatureweight 35 %0 %
- Seaweight 25 %0 %
- Sunshineweight 20 %33 %
- Few rainy daysweight 20 %34 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in September
- Sunscreen
- A jumper for the evenings
- Rain jacket or umbrella
Llanfairpwllgwyngyll in September: quick answers
Is Llanfairpwllgwyngyll hot in September?
No. In September, Llanfairpwllgwyngyll is mild: daytime highs average 16 °C and nights drop to about 12 °C.
Can you swim in Llanfairpwllgwyngyll in September?
Only if you don't mind cold water: in September the sea averages just 15.6 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Llanfairpwllgwyngyll in September?
Rain is frequent, with about 13 rainy days and 83 mm in total.
Llanfairpwllgwyngyll month by month
The whole year in LlanfairpwllgwyngyllAll destinations: United KingdomWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences