A Memorial Day 10K at 5,300 feet that finishes inside Folsom Field. Dry mountain air, strong sun, and a wide swing between the start and finish.
By Brett Heimlich, part-time runner.
Plan for about 49°F (9°C) at the 07:00 start, feeling like 45°F (7°C), with 79% humidity and 5 mph wind, warming to roughly 61°F (16°C) by the finish. It rained on 7 of the last 10 race days. Wear: Long Sleeve Tech Shirt, Capris or Light Tights, Running Cap, Waterproof Jacket.
49°F (9°C)
61°F (16°C)
7 of 10 years
41° to 54°F
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Conditions at the 07:00 start on the race's usual date each year (memorial Day (last Monday of May)). Years when the race was cancelled or moved still show that date's weather. Source: Open-Meteo ERA5 archive.
| Year | Start temp | Feels like | Finish | Humidity | Wind | Rain | Sky |
|---|---|---|---|---|---|---|---|
| 2025 | 47°F (8°C) | 44°F | 55°F | 95% | 4 mph | 0.57 in | Overcast |
| 2024 | 51°F (11°C) | 45°F | 69°F | 56% | 7 mph | – | Clear |
| 2023 | 52°F (11°C) | 49°F | 70°F | 71% | 3 mph | – | Clear |
| 2022 | 49°F (9°C) | 43°F | 56°F | 56% | 5 mph | 0.12 in | Drizzle |
| 2021 | 47°F (8°C) | 45°F | 50°F | 89% | 2 mph | 0.08 in | Drizzle |
| 2020 | 41°F (5°C) | 37°F | 54°F | 88% | 4 mph | – | Clear |
| 2019 | 46°F (8°C) | 43°F | 57°F | 83% | 3 mph | 0.31 in | Overcast |
| 2018 | 54°F (12°C) | 52°F | 60°F | 95% | 5 mph | 0.18 in | Mostly clear |
| 2017 | 49°F (9°C) | 44°F | 61°F | 73% | 5 mph | 0.16 in | Clear |
| 2016 | 49°F (9°C) | 44°F | 73°F | 82% | 7 mph | 0.06 in | Clear |
Coldest start: 41°F (5°C) in 2020. Warmest: 54°F (12°C) in 2018. Wettest: 0.57 in in 2025.
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
Light Gloves
Thin running gloves
Headband
Ear coverage without overheating
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 49°F (9°C) (feels like 45°F (7°C)) with 79% humidity and 5 mph wind, warming to about 61°F (16°C) by the finish. It rained measurably on 7 of those 10 race days. The coldest start was 41°F (5°C) in 2020; the warmest was 54°F (12°C) in 2018.
For a typical 49°F (9°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 Bolder Boulder is usually held on memorial Day (last Monday of May). The next expected date is Monday, May 31, 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.
Get a what-to-wear call for the live forecast at your exact location, free, no signup.
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