Daily rainfall, frost and wind for Portsmouth against the 10-year average — the starting point for any weather delay conversation on site.
Weather delay record
PO1 2EG · 1 Sept 2025 – 30 Sept 2025
Rainfall over this period was 101% of the 10-year average for the same calendar window at this location. Conditions were broadly in line with typical for the time of year. 2 days had gusts at or above 47 mph.
Rainfall vs 10-yr avg
101%
84 mm vs 83 mm typical
Rain days >5mm
3
typical: 5.1
Frost days
0
typical: 0.0
High-wind days
2
gusts ≥ 47 mph
Daily record
| Date | Rain (mm) | Min °C | Max °C | Gust (mph) | Flags |
|---|---|---|---|---|---|
| 1 Sept 2025 | 4.7 | 15.3 | 19.0 | 34 | |
| 2 Sept 2025 | 7.4 | 14.2 | 19.0 | 36 | wet |
| 3 Sept 2025 | 29.9 | 16.0 | 19.5 | 53 | wet · wind |
| 4 Sept 2025 | 4.5 | 14.2 | 18.8 | 38 | |
| 5 Sept 2025 | 0.2 | 12.0 | 19.7 | 22 | |
| 6 Sept 2025 | 0.0 | 14.3 | 20.3 | 34 | |
| 7 Sept 2025 | 0.1 | 16.2 | 22.0 | 30 | |
| 8 Sept 2025 | 0.5 | 13.9 | 18.4 | 27 | |
| 9 Sept 2025 | 2.7 | 13.2 | 18.5 | 28 | |
| 10 Sept 2025 | 12.5 | 14.1 | 17.3 | 33 | wet |
| 11 Sept 2025 | 0.5 | 13.3 | 17.2 | 43 | |
| 12 Sept 2025 | 1.8 | 12.2 | 16.9 | 40 | |
| 13 Sept 2025 | 4.3 | 12.3 | 17.0 | 36 | |
| 14 Sept 2025 | 3.7 | 9.7 | 17.9 | 45 | |
| 15 Sept 2025 | 0.6 | 14.3 | 17.3 | 51 | wind |
| 16 Sept 2025 | 0.3 | 12.8 | 17.7 | 32 | |
| 17 Sept 2025 | 3.2 | 13.7 | 17.9 | 47 | |
| 18 Sept 2025 | 1.3 | 16.0 | 19.0 | 36 | |
| 19 Sept 2025 | 0.0 | 14.6 | 21.2 | 19 | |
| 20 Sept 2025 | 3.2 | 13.2 | 19.3 | 43 | |
| 21 Sept 2025 | 0.1 | 9.0 | 15.0 | 30 | |
| 22 Sept 2025 | 0.0 | 7.8 | 15.7 | 26 | |
| 23 Sept 2025 | 0.0 | 6.7 | 16.2 | 23 | |
| 24 Sept 2025 | 0.0 | 9.5 | 16.9 | 27 | |
| 25 Sept 2025 | 0.0 | 9.0 | 17.7 | 28 | |
| 26 Sept 2025 | 0.3 | 8.6 | 14.2 | 19 | |
| 27 Sept 2025 | 0.9 | 10.9 | 15.6 | 29 | |
| 28 Sept 2025 | 1.5 | 11.2 | 17.0 | 20 | |
| 29 Sept 2025 | 0.0 | 8.9 | 17.8 | 12 | |
| 30 Sept 2025 | 0.0 | 8.2 | 17.3 | 13 |
3 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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