The Big Half
London, United Kingdom · Expected Sunday 5 September 2027Date to be confirmed
Difficulty Calculator
Adjusted Time
1:42:37
Time difference: -2.4 minutes compared to an average road half marathon.
Course Details
Typical Race-Day Weather
Average for this date over the last 8 years.
How hard is The Big Half?
On our difficulty model, The Big Half plays about 2 minutes faster than an average road half marathon for a 1:30 runner. It ranks #529 hardest of 634 half marathons we analyse, and #97 of 111 in United Kingdom. Use the calculator above to see the exact adjusted time for your own goal pace.
What will you run at The Big Half?
Estimated finish times on this course versus the same effort on an average road half marathon, based on its elevation, surface, and expected race-day temperature.
| Average-course time | On The Big Half | Difference |
|---|---|---|
| 1:30:00 | 1:27:42 | −02:18 |
| 1:45:00 | 1:42:37 | −02:23 |
| 2:00:00 | 1:57:31 | −02:29 |
| 2:15:00 | 2:12:24 | −02:36 |
| 2:30:00 | 2:27:17 | −02:43 |
| 2:45:00 | 2:42:09 | −02:51 |
| 3:00:00 | 2:57:01 | −02:59 |
Use the calculator above for your exact goal time. Want a prediction from your own training? Try the marathon time predictor.
The Big Half 2027 Course Analysis
The Big Half is a half marathon held in London, United Kingdom. The next edition is expected on Sunday 5 September 2027, following the pattern of previous editions (the 1st Sunday of September). The organisers have not confirmed it yet. The course is run on road surface with 37m of total climbing, with its high point near 12m above sea level. For registration and full race details, visit the official The Big Half website.
Climbing
At 37m of total climbing, it is flatter than 89% of the 634 half marathons we rate. That makes it one of the flatter courses we track, well suited to an even pace.
Race-day weather
Over the last 4 years this September date has averaged a high of 20°C and a low of 12°C. That is warmer than 54% of the half marathons we track.
On 5 September over the last 4 years, the high ranged from 17°C (2020) to 24°C (2021). It stayed dry on all of them.
| 5 September | High | Low | Rain | Wind |
|---|---|---|---|---|
| 2026 | 22°C | 13°C | dry | 10 km/h |
| 2021 | 24°C | 13°C | dry | 11 km/h |
| 2020 | 17°C | 11°C | dry | 17 km/h |
| 2019 | 17°C | 12°C | dry | 20 km/h |
Daily weather for the race location (Open-Meteo archive). Wind is the day's peak.
Looking for an easier marathon or a tougher challenge? You can also compare The Big Half against other half marathons to find the right race for your goals.
Half marathons of similar difficulty
If The Big Half fits your goal, these courses play out about the same on our difficulty model.
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