Daily rainfall, frost and wind for Swansea against the 10-year average — the starting point for any weather delay conversation on site.
Weather delay record
SA1 1NW · 1 Sept 2025 – 30 Sept 2025
Rainfall over this period was 163% of the 10-year average for the same calendar window at this location. Conditions were materially wetter than typical for the time of year. 1 day had gusts at or above 47 mph.
Rainfall vs 10-yr avg
163%
246 mm vs 151 mm typical
Rain days >5mm
15
typical: 9.4
Frost days
0
typical: 0.0
High-wind days
1
gusts ≥ 47 mph
Daily record
| Date | Rain (mm) | Min °C | Max °C | Gust (mph) | Flags |
|---|---|---|---|---|---|
| 1 Sept 2025 | 11.1 | 13.6 | 17.4 | 31 | wet |
| 2 Sept 2025 | 4.7 | 12.8 | 18.9 | 24 | |
| 3 Sept 2025 | 16.6 | 14.5 | 18.3 | 34 | wet |
| 4 Sept 2025 | 10.9 | 12.7 | 16.8 | 26 | wet |
| 5 Sept 2025 | 0.7 | 11.1 | 18.5 | 20 | |
| 6 Sept 2025 | 0.4 | 14.3 | 20.4 | 40 | |
| 7 Sept 2025 | 23.7 | 13.9 | 19.4 | 37 | wet |
| 8 Sept 2025 | 15.4 | 11.7 | 16.7 | 27 | wet |
| 9 Sept 2025 | 12.0 | 12.4 | 16.4 | 32 | wet |
| 10 Sept 2025 | 7.2 | 13.4 | 16.4 | 32 | wet |
| 11 Sept 2025 | 14.2 | 11.4 | 15.4 | 43 | wet |
| 12 Sept 2025 | 12.5 | 11.5 | 15.7 | 33 | wet |
| 13 Sept 2025 | 13.4 | 10.8 | 15.1 | 33 | wet |
| 14 Sept 2025 | 26.6 | 11.6 | 17.7 | 42 | wet |
| 15 Sept 2025 | 4.0 | 13.0 | 16.4 | 51 | wind |
| 16 Sept 2025 | 2.7 | 12.1 | 16.2 | 33 | |
| 17 Sept 2025 | 24.4 | 13.1 | 17.2 | 40 | wet |
| 18 Sept 2025 | 9.9 | 16.3 | 17.8 | 34 | wet |
| 19 Sept 2025 | 3.0 | 15.4 | 18.0 | 28 | |
| 20 Sept 2025 | 19.8 | 10.6 | 17.5 | 43 | wet |
| 21 Sept 2025 | 0.3 | 8.6 | 14.4 | 21 | |
| 22 Sept 2025 | 0.0 | 6.1 | 15.2 | 17 | |
| 23 Sept 2025 | 0.0 | 6.4 | 15.5 | 16 | |
| 24 Sept 2025 | 0.0 | 7.6 | 16.4 | 15 | |
| 25 Sept 2025 | 0.0 | 8.7 | 17.3 | 19 | |
| 26 Sept 2025 | 0.0 | 8.2 | 15.6 | 19 | |
| 27 Sept 2025 | 12.0 | 12.0 | 16.4 | 29 | wet |
| 28 Sept 2025 | 0.1 | 8.3 | 16.5 | 21 | |
| 29 Sept 2025 | 0.0 | 7.2 | 15.3 | 10 | |
| 30 Sept 2025 | 0.1 | 10.3 | 15.0 | 18 |
15 days with rainfall over 5 mm in this period.
Data: ERA5 reanalysis via Open-Meteo, taken at the nearest model grid point to the postcode — not a Met Office station record. Baselines are the mean of the same calendar months over the previous 10 years at this location. Whether conditions meet a contractual test (e.g. JCT “exceptionally adverse weather” or an NEC 1-in-10-year event) is a matter for the contract — this is a factual weather record, not advice.
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