YMCA Famous Idaho Potato Marathon weather.
Typically 11°C on race morning; rain in 2 of the last 10 years. Race morning (07:00 to 11:00 local time) in Boise on race day in each of the last 10 years; the 2027 race is on 15 May 2027.
- Typical
- 11°C (52°F)
- race-morning average
- Coolest
- 2°C (36°F)
- lowest reading, 07:00–11:00
- Warmest
- 22°C (72°F)
- highest reading, 07:00–11:00
- Wet years
- 2 of 10
- rain, drizzle or worse
- Humidity
- 54%
- typical
- Wind
- 9 km/h
- typical, at 10 m
Race morning, 07:00–11:00
Year by year
| Race day | Average | Low–high | Humidity | Wind | Rain | Conditions |
|---|---|---|---|---|---|---|
| 16 May 2026 | 11°C (53°F) | 10°C (49°F)–13°C (56°F) | 42% | 19 km/h | 0.0 mm | Mainly clear |
| 17 May 2025 | 12°C (54°F) | 10°C (50°F)–14°C (58°F) | 62% | 14 km/h | 0.3 mm | Overcast |
| 18 May 2024 | 11°C (51°F) | 5°C (41°F)–16°C (60°F) | 42% | 4 km/h | 0.0 mm | Partly cloudy |
| 13 May 2023 | 17°C (62°F) | 11°C (51°F)–22°C (71°F) | 41% | 7 km/h | 0.0 mm | Clear |
| 14 May 2022 | 11°C (52°F) | 10°C (50°F)–13°C (56°F) | 74% | 8 km/h | 1.3 mm | Drizzle |
| 15 May 2021 | 14°C (58°F) | 11°C (52°F)–18°C (65°F) | 45% | 4 km/h | 0.0 mm | Overcast |
| 16 May 2020 | 12°C (54°F) | 6°C (43°F)–17°C (63°F) | 46% | 19 km/h | 0.0 mm | Overcast |
| 18 May 2019 | 10°C (50°F) | 8°C (47°F)–13°C (55°F) | 79% | 10 km/h | 0.0 mm | Mainly clear |
| 12 May 2018 | 11°C (52°F) | 8°C (47°F)–14°C (56°F) | 66% | 6 km/h | 0.7 mm | Overcast |
| 13 May 2017 | 6°C (43°F) | 2°C (36°F)–10°C (50°F) | 70% | 12 km/h | 0.1 mm | Clear |
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 marathon starts at 07:00.
Kit and pacing
What it means
Good racing weather
Around 11°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.
Have a warm-day plan
In the warmest of these years it reached 22°C by late morning. Decide in advance how much you'd slow down if the forecast is warm, rather than on the course.
It can be cold
The coolest morning here dropped to 2°C. Pack gloves and a throwaway layer even if the forecast looks kind.
The weather varies a lot
Race mornings here have ranged by 10°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).