Fall Equinox 2025 Marathon. The fall equinox marathon, taking place on september 22, 2025, in fort collins, co, features a scenic and challenging course through the buckhorn and poudre river. But we consider the sun to be rising when the lip of it just comes.
The fall equinox is on sunday september 22, 2025 to saturday october 5, 2025. One of the best races in colorado!