Chicago's spring kickoff, a flat 8K through the Loop from Grant Park. Late March by the lake can be anything from snow flurries to a sunny 60°F.
Plan for about 38°F (3°C) at the 08:00 start, feeling like 29°F (-2°C), with 71% humidity and 11 mph wind, warming to roughly 38°F (3°C) by the finish. It rained on 5 of the last 10 race days. Wear: Long Sleeve Base Layer, Running Tights, Running Gloves, Beanie or Ear Warmers, Running Cap.
Feels like 29°F (-2°C) at the start · finish 38°F (3°C) · rain 5 of 10 · start air from 25°F (-4°C) to 52°F (11°C)
Conditions at the 08:00 start on the race's usual date each year (fourth Sunday of March). 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 | 39°F (4°C) | 30°F | 39°F | 62% | 11 mph | 0.29 in | Overcast |
| 2024 | 34°F (1°C) | 24°F | 34°F | 64% | 12 mph | – | Overcast |
| 2023 | 39°F (4°C) | 34°F | 39°F | 74% | 2 mph | – | Overcast |
| 2022 | 25°F (-4°C) | 12°F | 25°F | 50% | 16 mph | – | Clear |
| 2021 | 39°F (4°C) | 27°F | 39°F | 71% | 20 mph | – | Overcast |
| 2020 | 32°F (0°C) | 21°F | 32°F | 64% | 12 mph | 0.21 in | Overcast |
| 2019 | 42°F (6°C) | 38°F | 42°F | 86% | 2 mph | 0.24 in | Overcast |
| 2018 | 29°F (-2°C) | 17°F | 29°F | 56% | 14 mph | – | Mostly clear |
| 2017 | 52°F (11°C) | 48°F | 52°F | 97% | 10 mph | 0.66 in | Rain |
| 2016 | 44°F (7°C) | 38°F | 44°F | 83% | 7 mph | 0.27 in | Overcast |
Coldest start: 25°F (-4°C) in 2022. Warmest: 52°F (11°C) in 2017. Wettest: 0.66 in in 2017.
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.
Advertisement
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 Base Layer
Lightweight thermal top
Running Vest or Light Jacket
Extra warmth for core
Running Tights
Full-length compression tights
Running Gloves
Touchscreen-compatible warmth
Beanie or Ear Warmers
Head and ear protection
Running Cap
Keep rain out of eyes
Trail or Waterproof Shoes
Better grip and water resistance
Wool Running Socks
Warm and moisture-wicking
✓ Worn by the author
Grid-fleece quarter zip for 25 to 40°F starts
$128
✓ Worn by the author
Compression tight for 40 to 55°F, works under shorts
$78
Touchscreen-compatible, windproof, and packable
$55
Warm, itch-free merino blend for cold runs
$38
✓ Worn by the author
Thin, ribbed quarter sock that keeps grit out
$36
As an Amazon Associate, we earn from qualifying purchases. Some links may earn a commission at no extra cost to you.
Over 2016 to 2025 the start averaged 38°F (3°C) (feels like 29°F (-2°C)) with 71% humidity and 11 mph wind, warming to about 38°F (3°C) by the finish. It rained measurably on 5 of those 10 race days. The coldest start was 25°F (-4°C) in 2022; the warmest was 52°F (11°C) in 2017.
For a typical 38°F (3°C) start: Long Sleeve Base Layer, Running Tights, Running Gloves, Beanie or Ear Warmers, Running Cap. 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 Bank of America Shamrock Shuffle is usually held on fourth Sunday of March. The next expected date is Sunday, March 28, 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.
Check your live running weatherAdvertisement