Downtown Indianapolis out to a full lap of the Indianapolis Motor Speedway and back. Early May in Indiana swings from chilly and wet to warm and humid, sometimes with storms.
Plan for about 54°F (12°C) at the 07:00 start, feeling like 50°F (10°C), with 76% humidity and 7 mph wind, warming to roughly 59°F (15°C) by the finish. It rained on 3 of the last 10 race days. Wear: Long Sleeve Tech Shirt, Capris or Light Tights, Running Cap, Waterproof Jacket.
Feels like 50°F (10°C) at the start · finish 59°F (15°C) · rain 3 of 10 · start air from 41°F (5°C) to 61°F (16°C)
Conditions at the 07:00 start on the race's usual date each year (first Saturday of May). Years when the race was cancelled or moved still show that date's weather. Source: Open-Meteo ERA5 archive.
Bar: air temperature from start to finish · dot: feels-like effective temperature · ≫ windy (15+ mph) · rain · shaded: PR band 40–50°F
| Year | Start temp | Feels like | Finish | Humidity | Wind | Rain | Sky |
|---|---|---|---|---|---|---|---|
| 2025 | 55°F (13°C) | 54°F | 57°F | 92% | 5 mph | 0.16 in | Overcast |
| 2024 | 61°F (16°C) | 62°F | 68°F | 94% | 6 mph | 0.05 in | Clear |
| 2023 | 57°F (14°C) | 52°F | 61°F | 65% | 7 mph | – | Overcast |
| 2022 | 52°F (11°C) | 45°F | 56°F | 64% | 12 mph | – | Mostly clear |
| 2021 | 41°F (5°C) | 34°F | 49°F | 65% | 6 mph | – | Clear |
| 2020 | 57°F (14°C) | 51°F | 65°F | 60% | 10 mph | – | Mostly clear |
| 2019 | 53°F (12°C) | 51°F | 53°F | 96% | 7 mph | 0.31 in | Drizzle |
| 2018 | 56°F (13°C) | 54°F | 64°F | 78% | 4 mph | – | Overcast |
| 2017 | 44°F (7°C) | 38°F | 50°F | 77% | 7 mph | – | Overcast |
| 2016 | 60°F (16°C) | 56°F | 67°F | 67% | 10 mph | – | Overcast |
Coldest start: 41°F (5°C) in 2021. Warmest: 61°F (16°C) in 2024. Wettest: 0.31 in in 2019.
The time estimates apply published temperature–performance curves to this race's ten-year weather history. Performance peaks at an effective race temperature of roughly 40 to 50°F and degrades faster the warmer it gets and the slower you run (Ely et al., 2007; El Helou et al., 2012). Wind adds a cost that grows with the square of the wind speed (Pugh, 1971), split into head and tail components on point-to-point courses. Shorter races are penalised less. This is a model, not a prediction; your training and the course matter more.
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Built from the 10-year average start conditions by the same engine as the live tool. Treat optional items as corral-only layers you can shed.
Long Sleeve Tech Shirt
Breathable moisture-wicking fabric
Waterproof Jacket
Breathable rain protection
Capris or Light Tights
3/4 length for moderate warmth
Running Cap
Keep rain out of eyes
Trail or Waterproof Shoes
Better grip and water resistance
✓ Worn by the author
Compression tight for 40 to 55°F, works under shorts
$78
✓ Worn by the author
Fast-drying micromesh tee for warm-weather miles
$75
Packable wind shell for cool morning miles
$115
✓ Worn by the author
Thin, ribbed quarter sock that keeps grit out
$36
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Over 2016 to 2025 the start averaged 54°F (12°C) (feels like 50°F (10°C)) with 76% humidity and 7 mph wind, warming to about 59°F (15°C) by the finish. It rained measurably on 3 of those 10 race days. The coldest start was 41°F (5°C) in 2021; the warmest was 61°F (16°C) in 2024.
For a typical 54°F (12°C) start: Long Sleeve Tech Shirt, Capris or Light Tights, Running Cap, Waterproof Jacket. Dress for about 15°F warmer than the start temperature, since the race itself adds that much, and plan to shed anything you only need in the corral.
The 500 Festival Mini-Marathon is usually held on first Saturday of May. The next expected date is Saturday, May 1, 2027. Confirm on the official site, since dates occasionally move.
The live forecast on this page comes from Open-Meteo and unlocks 16 days before the race. Forecasts inside 7 days are reliable for temperature within a few degrees; rain timing firms up in the last 2 to 3 days. Until then, the 10-year history above is the best planning guide.
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