National Cycle Network Route 4, stage 3: Bath → Pontypridd
On stage 3 (Bath → Pontypridd, 129 km) the best month is September: 77% of days were dry with highs of 10–30 °C, and riding Pontypridd → Bath meant an average tailwind of 3.7 km/h (ERA5 2006–2025, 9:00–18:00).
← National Cycle Network Route 4 (Whole route)
Weather by month
| Month | Good days | Rain days ≥ 1 mm | Rain, mm | Avg high | Days ≥ 30 °C | Days < 10 °C | Daylight, h |
|---|---|---|---|---|---|---|---|
| January | 16% | 25% | 77 | 8 °C | 0% | 74% | 8.3 † |
| February | 23% | 24% | 66 | 8 °C | 0% | 68% | 9.9 † |
| March | 41% | 26% | 66 | 10 °C | 0% | 46% | 11.7 |
| April | 67% | 24% | 52 | 13 °C | 0% | 13% | 13.8 |
| May | 71% | 29% | 74 | 16 °C | 0% | 1% | 15.6 |
| June | 75% | 25% | 67 | 19 °C | 0% | 0% | 16.6 |
| July | 73% | 26% | 73 | 21 °C | 1% | 0% | 16.2 |
| August | 73% | 26% | 75 | 20 °C | 1% | 0% | 14.6 |
| September | 77% | 23% | 67 | 18 °C | 0% | 0% | 12.6 |
| October | 72% | 26% | 88 | 15 °C | 0% | 3% | 10.6 † |
| November | 46% | 27% | 89 | 11 °C | 0% | 33% | 8.8 † |
| December | 23% | 26% | 89 | 9 °C | 0% | 60% | 7.8 † |
Best months are all months within 3 percentage points of the best one. † less than 11 hours of daylight — long stages get tight.
Wind by month
| Month | Wind Bath → Pontypridd, km/h | Headwind > 15 km/h, Bath → Pontypridd | Headwind > 15 km/h, Pontypridd → Bath | Better way |
|---|---|---|---|---|
| January | −4.5 | 22% | 7% | Pontypridd → Bath |
| February | −3.5 | 23% | 10% | Pontypridd → Bath |
| March | −2.2 | 19% | 12% | Pontypridd → Bath |
| April | −0.7 | 15% | 12% | either |
| May | −2.8 | 20% | 8% | Pontypridd → Bath |
| June | −3.7 | 19% | 6% | Pontypridd → Bath |
| July | −6.3 | 25% | 4% | Pontypridd → Bath |
| August | −6.1 | 25% | 4% | Pontypridd → Bath |
| September | −3.7 | 19% | 6% | Pontypridd → Bath |
| October | −2.5 | 18% | 9% | Pontypridd → Bath |
| November | −3.4 | 19% | 8% | Pontypridd → Bath |
| December | −4.4 | 22% | 7% | Pontypridd → Bath |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 244–269 | NW | −3.1 |
| 269–297 | N | +1.2 |
| 297–322 | SW | −5.7 |
| 322–347 | W | −5.4 |
| 347–373 | W | −5.7 |
Other stages
- London → Reading 116 km
- Reading → Bath 128 km
- Bath → Pontypridd 129 km
- Pontypridd → Carmarthen 126 km
- Carmarthen → Fishguard 147 km
How to read the numbers
Wind is the 10 m wind of a 25-km grid cell, daytime hours 9:00–18:00 local solar time; at saddle height in a sheltered valley it is weaker, on a coast or ridge stronger. A positive value is a tailwind. ERA5 slightly over-counts days with ≥ 1 mm of rain (by about 5–7 percentage points) and underestimates daily highs by 1–2 °C. Good day = less than 1 mm of rain between 9:00 and 18:00 (riding hours, local solar time) and a high between 10 and 30 °C; rain at night or in the evening does not spoil it.