US Races This Weekend (Sept. 12–13, 2026): Start Times, Deadlines and a 27-Degree Forecast Spread

Quick answer — Saturday's biggest fields are REVEL Big Cottonwood outside Salt Lake City and the Bar Harbor Bank & Trust Half in Maine at 7 a.m. Sunday belongs to the Erie Marathon at Presque Isle, also 7 a.m., where 68°F and 88% humidity make it the warmest, stickiest start on the board.

Two Septembers ago this same weekend was the quiet one before the fall calendar opened. Not this year: there are marathons on both days, three half marathons starting within five minutes of each other in Washington state, and a forecast that swings 27 degrees depending on which time zone you woke up in.

What races are running this Saturday, Sept. 12?

The Bar Harbor race also sends half marathon walkers off at 6:15 a.m., 45 minutes ahead of the runners.

What about Sunday, Sept. 13?

Forecasts are National Weather Service hourly data for the start hour, pulled Sept. 8. Five days out, expect the temperature to hold within a few degrees and the rain probability to move more than that.

Which entries are about to get more expensive?

Four of the ten step up in price or close online entry before the gun. These are the final published windows on each event's registration page.

• Bar Harbor — last online window is $160 for the half and $45 for the 5K, closing ahead of race day.
• Geist — final online price $116.99 for the half, $81.99 for the 10K, closing the day before.
• Black Squirrel — $110 online, $125 if you enter on race morning.
• Holland Haven — closes the evening before: marathon $159, half $154, 8K $64.

Erie is the outlier. Its price already stepped from $120 to $150 at the start of September, and entry stays open into race morning at the higher rate.

What should you wear at these temperatures?

A useful rule: dress for roughly 15 to 20 degrees warmer than the thermometer says, because that is where your body lands ten minutes in.

Bozeman at 41°F is the only true cold start. That means a long-sleeve base under a singlet, light gloves you can stuff in a waistband, and full-length tights — a pair in the $17 to $45 range does the job as well as a $108 one, and you can compare current prices at our sister site Activewear Deals.

Erie at 68°F with 88% humidity is the opposite problem. Sweat will not evaporate. Singlet, split shorts or a five-inch short, and a plan to take fluid at every aid station rather than every other one.

Everything in the 53°F to 56°F band — Gig Harbor, Salem, Bar Harbor, Bellvue — is close to ideal racing weather. Shorts and a short-sleeve, with a throwaway layer for the corral. Full breakdown in our temperature chart.

Which race is the interesting one?

Erie, for a reason that has nothing to do with the weather. Its own race information calls the course about as flat as they come — "less than a 250-foot total change in elevation for the marathon" — run inside Presque Isle State Park, with aid stations roughly a mile apart carrying water, lemon-lime sports drink and a portable toilet at each one.

What if you have not entered anything?

Three of these still take entries on race morning: Erie, Black Squirrel and Race For A Soldier, where the Sunday half is $100 at the line. Race-day pricing runs $15 to $30 above the online rate, which is the cost of deciding late.

First time doing any of this? Our first race checklist covers the night before and the 90 minutes that matter most.

How accurate is a five-day race forecast?

Temperature at five days is usually within a few degrees. Rain probability is the number that moves — Bozeman's 48% chance is a genuine coin flip and worth re-checking Friday.

Do I need a jacket for a 41-degree start?

Not for the running. For the 40 minutes of standing around before the gun, yes — and something you are willing to abandon at the start line is the standard answer.

Why do the Washington races start five minutes apart?

Race For A Soldier sends the half at 7:50, the 10K at 7:55 and the 5K at 8:00 so the fields separate on a shared early course. Line up in the right group and the first mile is far less crowded.

TL;DR — Ten verified races, Sept. 12–13. Coldest start Bozeman at 41°F, warmest and stickiest Erie at 68°F and 88% humidity. Four entry deadlines fall Wednesday through Saturday. Race-morning entry is still possible at Erie, Black Squirrel and Race For A Soldier.

What is on next weekend, Sept. 18–19?

The Air Force Marathon, and it is a two-day event rather than a Saturday morning. Race weekend runs Sept. 18–19, 2026 at the National Museum of the United States Air Force in Dayton, Ohio.

A Friday evening 5K followed by a Saturday dawn marathon is a genuinely different kit problem: one run at dusk in September warmth, one at 6:30 a.m. when it is 20 degrees cooler. Our what-to-wear coverage and the daily weather page both track that split.

Sources

• Race dates, start times and entry pricing: each event's own registration page, linked in the tables above; eriemarathon.net for Erie; runrevel.com/bcm for Big Cottonwood.
• Forecasts: National Weather Service hourly forecast data for each start location, retrieved Sept. 8, 2026.
• Boston qualifying window dates: Boston Athletic Association.