The Short Answer
On the Endurance Grid calendar, marathons run all year, with peaks in fall and spring. October 2026 held 78, the most of any month since May 16, 2026, and the busiest month listed so far for 2027 is April, with 71. Summer is the quiet stretch, and Florida, Texas, and California lead the winter.
Based on 237 marathons held on the Endurance Grid calendar since May 16, 2026, when our race history begins, and 416 listed ahead, as of November 8, 2026. We don't list every marathon in the US.
Races by Month
Our race history begins on May 16, 2026, so the first column covers the months since then. The second column is what race directors have listed with us so far. Listings fill in as races get closer, so the later months will keep rising.
Month | Held in 2026 | Listed so far, Nov 2026 to Oct 2027 |
|---|---|---|
January | — | 32 in 12 states |
February | — | 41 in 15 states |
March | — | 33 in 20 states |
April | — | 71 in 33 states |
May | 13 in 10 states (from May 16) | 43 in 22 states |
June | 31 in 18 states | 24 in 14 states |
July | 15 in 12 states | 11 in 8 states |
August | 20 in 13 states | 14 in 10 states |
September | 54 in 31 states | 19 in 14 states |
October | 78 in 30 states | 30 in 19 states |
November | 26 in 16 states (through Nov 7) | 51 in 23 states (Nov 8 on) |
December | — | 41 in 20 states |
Fall: The Busiest Stretch
Since our history began, marathons on our calendar jumped from 20 in August to 54 in September and 78 in October, the busiest month so far. September and October each had marathons in 30 or more states. See October races.
Spring: April Leads 2027 So Far
For 2027, April has the most marathons listed so far, with 71 in 33 states, more than twice March's 33. May is next, with 43. See April races.
Summer: The Quiet Stretch
Summer is the slowest season for marathons on our calendar. In 2026, July held 15 and August 20, compared with October's 78.
Winter Marathons
Marathons keep going through the winter. For December 2026 through February 2027, our calendar lists 114 so far, led by Florida (36), Texas (15), and California (9).
Marathons That Also Offer a Half
Of the 416 marathons listed ahead on our calendar, 369 also offer a half marathon. See When Is Half Marathon Season? for the half marathon calendar.
Upcoming Marathons
The Next Marathons on Our Calendar
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