Marathon race-morning weather, coolest to warmest.

What the table shows

The coolest typical start is Philadelphia’s: 41°F with a 32°F dew point at 7am, a score of 73. Columbus (79) and Colfax (81) come next. Each race is read at its own start time, so an early gun counts in its favor.

Seven of the 24 start above 100 on a typical morning, the point where I start adjusting pace: Honolulu, Rock 'n' Roll San Diego, Grandma's, Rock 'n' Roll Nashville, OC, San Francisco and Flying Pig. For those, plan on a warm race and be pleasantly surprised, not the other way around.

The biggest change over the morning is Columbus’s: a typical score of 79 at the start and 95 three hours later. A runner finishing in four hours races in different weather than one finishing in three, so the later column is the one to read if you’re out there longer.

The warmest race morning in the table was the Honolulu Marathon in 2025: 74°F with a 71°F dew point at the start, a score of 145.

Cool and flat: Columbus, CIM, Detroit, Houston, Eugene, Twin Cities and Jersey City sit in the cooler half here and the flatter half of the course elevation comparison. If the goal is a fast time, that’s where I’d start looking.

How I measured them

Every race morning comes from a long-record NOAA/FAA weather station near the course (ASOS, via the Iowa Environmental Mesonet): the reading nearest each race’s first-wave start and three hours later, on every race morning since 2000, or since the race began. The typical start is the median of those mornings. Each race is read at its own start time, because that is the weather its runners actually start in, so an early gun is part of why a race ranks cool. The score adds the air temperature to the dew point, both in Fahrenheit, the same as my heat pace calculator: 100 or less needs no pace adjustment, and the bands above it are on every race page. A station can sit a few miles from the course, so treat a single morning as close, not exact. Each race’s page has every morning, hour by hour.