BestRaces| Distances | 15K |
| Surface | trail |
| Field size | 194 runners |
| USATF certified | N/A (trail) |
| Boston qualifier | No |
From the race's RunSignup listing, with field size from its posted results, last updated September 23, 2026.
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Race-day weather
What the weather did on January 30 in each of the last 5 years, measured at Weldon Spring Nws, 14.3 miles from Foristell.
| Year | High | Low | Rain |
|---|---|---|---|
| 2026 | 27°F | 7°F | none |
| 2025 | 56°F | 35°F | 0.23 in |
| 2024 | 55°F | 28°F | none |
| 2023 | 27°F | 17°F | 0.06 in |
| 2022 | 47°F | 11°F | none |
Daily highs and lows, not start-line temperatures: most races start in the cool of the morning, closer to the low. Source: NOAA National Centers for Environmental Information, GHCN-Daily.
Stay near Foristell
Hotels and rentals in and around Foristell, MO.
Preset to race weekend, Jan 29 – 31.
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Race Pace Analyzer beta
Build your Castlewood Cup splits
This one already knows the course. Give it your goal time and it gives you every split to the finish, adjusted for this race's terrain and its usual race-morning temperature, plus a fueling plan and a check on whether the goal fits your fitness. It's free, and there's nothing to sign up for.
- Already loaded
- 15K
- Trail underfoot
- ≈20°F on January race mornings
| Mile | Split | Elapsed |
|---|
Training paces for this goal
The everyday paces that build the fitness behind your goal, worked out from your target with the Daniels VDOT model. Save these for your next training block.
Treat these as a guide. Run easy days by feel, and adjust for heat, hills and how your legs feel that day.
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Beta. The splits are exact math on your goal time. The terrain and weather notes are estimates from this race's listing, not a forecast.
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