The usually brisk October air that frames Twin Cities marathon weekend gave way to something more like midsummer as near-90 degree heat greeted thousands of runners on the first day of the races. Participants in the 10-mile and half-marathon events said they struggled with conditions that race organizers and medical staff characterized as exceptional for the region and time of year.

“It felt like July out there — the sun was relentless,” said Hannah Peterson, 27, who completed the half marathon. “We went out fast because it felt fine at the start, but by mile eight the heat was beating everyone down.” Race volunteers handed out extra ice and towels as medical tents filled with runners suffering from dizziness, nausea and cramps.

Organizers said they had prepared heat protocols after weekend forecasts indicated an unusual heat wave, adding additional hydration and cooling stations along the course and expanding medical staffing. “We activated our heat contingency plan and increased supplies and personnel,” a race official said. “Our priority was keeping people safe while allowing the event to continue.”

Medical teams reported treating multiple cases of heat-related illness, providing IV hydration and on-site cooling for several runners before returning them to their families or transferring to local hospitals as needed. Emergency responders and volunteer medics coordinated with city services to ensure rapid response in high-traffic areas, and officials urged recreational participants to scale back goals and seek aid if they felt off.

Beyond immediate medical concerns, the heat posed logistical and economic challenges. Marathon weekend draws tens of thousands of spectators and contributes millions to the local economy through hotels, restaurants and retail. Hot weather can dampen spectator turnout, shorten stays and affect hospitality revenue, even as it demands more municipal resources and emergency readiness. “We prepare for large crowds, but not necessarily for a sustained surge in EMS calls tied to heat,” a Minneapolis public safety official said.

The event also highlighted broader industry trends. Race directors across the country have increasingly incorporated climate-flexible planning — from adjusting start times to creating more aggressive cooling and communication strategies — as unusually high temperatures and volatile weather patterns become more common. Insurance costs for events are rising, and some organizers are exploring staggered starts, stricter medical-clearance checks and contingency refunds to manage liability and participant safety.

Public-health experts say the incident in the Twin Cities mirrors a nationwide reality: the window of comfortable outdoor-season weather is shrinking. “Organized sports and mass-participation events must adapt to a higher baseline of heat risk,” said a University of Minnesota sports medicine specialist. “This isn’t just about elite performance; it’s about equitable access to safe recreation for all ages and abilities.”

For many runners, the day was a test of grit; for organizers and city officials, it was a rehearsal for future extremes. As the rest of marathon weekend proceeds, officials pledged to review response data and participant feedback, with an eye toward long-term changes in scheduling and infrastructure. The heat in early October was a clear reminder that climate variability is now an operational factor for community traditions once governed chiefly by the calendar.