Mizuno Swansea Half Marathon weather.
Typically 7°C on race morning; rain in 2 of the last 10 years. Race morning (07:00 to 11:00 local time) in Swansea on race day in each of the last 10 years; the 2027 race is on 21 Mar 2027.
- Typical
- 7°C (45°F)
- race-morning average
- Coolest
- -1°C (30°F)
- lowest reading, 07:00–11:00
- Warmest
- 11°C (52°F)
- highest reading, 07:00–11:00
- Wet years
- 2 of 10
- rain, drizzle or worse
- Humidity
- 77%
- typical
- Wind
- 19 km/h
- typical, at 10 m
Race morning, 07:00–11:00
Year by year
| Race day | Average | Low–high | Humidity | Wind | Rain | Conditions |
|---|---|---|---|---|---|---|
| 22 Mar 2026 | 8°C (46°F) | 4°C (40°F)–11°C (53°F) | 68% | 2 km/h | 0.0 mm | Clear |
| 23 Mar 2025 | 9°C (48°F) | 8°C (46°F)–11°C (51°F) | 90% | 22 km/h | 0.0 mm | Overcast |
| 24 Mar 2024 | 7°C (45°F) | 6°C (42°F)–9°C (49°F) | 75% | 21 km/h | 0.0 mm | Partly cloudy |
| 19 Mar 2023 | 5°C (42°F) | 3°C (38°F)–8°C (47°F) | 85% | 9 km/h | 0.0 mm | Overcast |
| 20 Mar 2022 | 6°C (43°F) | 5°C (41°F)–8°C (47°F) | 58% | 23 km/h | 0.0 mm | Clear |
| 21 Mar 2021 | 9°C (48°F) | 8°C (46°F)–10°C (51°F) | 83% | 11 km/h | 0.0 mm | Overcast |
| 22 Mar 2020 | 5°C (40°F) | 3°C (37°F)–7°C (45°F) | 71% | 18 km/h | 0.0 mm | Mainly clear |
| 24 Mar 2019 | 6°C (44°F) | 4°C (40°F)–9°C (48°F) | 78% | 12 km/h | 0.0 mm | Clear |
| 18 Mar 2018 | -1°C (31°F) | -1°C (30°F)–0°C (33°F) | 71% | 27 km/h | 1.3 mm | Light snow |
| 19 Mar 2017 | 10°C (51°F) | 10°C (50°F)–11°C (52°F) | 87% | 31 km/h | 0.3 mm | Light drizzle |
Each row is the race's date that year where we know it, else the same weekday nearest its usual date. Temperatures and humidity are averaged over 07:00 to 11:00 local time, rain is the total over those hours, and conditions are the commonest over the morning. The half marathon starts at 09:00.
Kit and pacing
What it means
Good racing weather
Around 7°C is close to ideal for a fast time. Shorts and a vest are enough once you're moving; bring a throwaway layer for the wait in the start pen.
It can be cold
The coolest morning here dropped to -1°C. Pack gloves and a throwaway layer even if the forecast looks kind.
Expect wind
Wind was 19 km/h on a typical morning here. Run in a group on exposed stretches, and aim for even effort rather than even splits: time lost into a headwind isn't all won back with it behind you.
The weather varies a lot
Race mornings here have ranged by 11°C from year to year. Pack for both, and settle your kit and pacing from the forecast in the last few days.
General guidance from past years' numbers. Check the forecast in race week.
Weather data by Open-Meteo.com, from its historical weather archive (CC BY 4.0).