A half marathon in September is the perfect dress rehearsal for the Chicago Marathon. You get a real race effort, full logistics practice, and a clear read on your fitness before taper. Plenty of Chicagoland runners use the races below as their final tune up four to six weeks before marathon day.
I used the Chicago 13.1 in June as my primary fitness check in 2024, but a lot of runners want one more race effort closer to marathon day. The September window is the right call. Far enough out to recover, close enough to give you real data on fitness and pacing. The races below are what Chicago area runners actually use. Hidden Gem keeps coming up because it fits the training calendar almost perfectly.
Featured Tune Up: Hidden Gem Half Marathon
Hidden Gem Half Marathon
The Hidden Gem is the go to September half marathon for Chicago Marathon runners. It is designed with marathon training in mind, lands in the sweet spot about four weeks before race day, and has strong community support from start to finish.
Why it works so well as a tune up:
- Perfect timing in the training calendar for most Chicago Marathon plans.
- Honest course that gives a true fitness checkpoint, not a fluke time.
- Excellent volunteers, neighborhood support, and pacing groups.
- Enough hills and turns to make you work without breaking you.
If you only pick one September half marathon before Chicago, most local runners would tell you to make it Hidden Gem.
How to race it
Treat Hidden Gem like a serious workout, not an all out life or death PR attempt. Aim for something around your realistic half marathon effort, but remember the real goal is to arrive at the start line of the marathon healthy and confident.
Other Strong September Half Marathons
If Hidden Gem is full or does not fit your schedule, there are plenty of other races that work well as tune ups. All of these sit in that late summer to early fall window and are used by Chicago Marathon runners every year.
Life Time Chicago Half Marathon
Big city race feel with closed roads, sections of Lake Shore Drive, and a flat, fast course. Great if you want something that feels close to a marathon environment with large crowds and strong support.
Best for: runners who like big race energy, wide roads, and a clear PR style course.
Official siteFox Valley Half Marathon
Scenic course along the Fox River with a calmer, more focused vibe than a big city race. Well organized, steady support, and a great place to lock in marathon pace without distraction.
Best for: runners who prefer quiet paths, consistent pacing, and less crowd chaos.
Official siteSummer Sizzler Chicago Half Marathon
Smaller half marathon used by some runners as an earlier September tune up. Very flat course and a simpler race day experience if you want to avoid big race logistics.
Best for: runners who want an earlier checkpoint or cannot make the mid to late September dates.
RegistrationNaperville Trails Half Marathon
Trail focused half marathon on paths and forest preserve style terrain. Lower key than a city road race and a nice change of scenery if most of your long runs are already on pavement.
Best for: runners who want a softer surface and quieter tune up that still covers the full 13.1 miles.
Event pageHub City Half Marathon
A smaller regional half marathon that some Chicago area runners use when the big names are sold out or the dates do not line up. Expect a simple race day setup and a focus on getting the miles in.
Best for: runners who want a low key, no fuss race to log a race effort.
Event pageCARA Ready to Run 20 Miler
Not a race, but a fully-supported 20-mile training run with a point-to-point course along Chicago's lakefront. Perfect for runners who want to hit that crucial long run distance with aid stations, pacing support, and no pressure to race all-out.
Best for: runners who want the full 20-mile experience with support but without the race day intensity.
Event pageHow to Choose Your Tune Up Race
Pick by timing
- If you want the classic four week out rehearsal, Hidden Gem is the obvious choice.
- If you like a later tune up, Chicago Half often lands two to three weeks before marathon day.
- If you prefer an earlier September checkpoint, Summer Sizzler or Fox Valley can fit better.
Pick by vibe
- Choose Hidden Gem or Chicago Half if you want big energy, crowds, and lots of runners around your pace.
- Choose Fox Valley or Naperville Trails if you want scenic paths and a calmer environment.
- Choose Hub City or other small events if you only care about getting in 13.1 at effort without extra noise.
One good rule of thumb
For a Chicago Marathon tune up, you want a race that is logistically simple for you to reach, likely to go off as planned, and close enough to your goal pace that you can practice nutrition and pacing. The exact brand on the bib matters less than execution.
How to Use a Half Marathon as a Tune Up
Treat it as a full dress rehearsal
- Wear the shoes, socks, shorts, and top you plan to use on marathon day.
- Eat the same breakfast you plan to use before the marathon.
- Practice your gel schedule and water intake exactly as you hope to do later.
Do not bury yourself
- Run hard enough to get real data, but not so hard that you need two full weeks to recover.
- Back off a little if the race is within three weeks of your marathon.
- Take five to seven days of easier running after the race before jumping back into big workouts.
Use the result to adjust expectations
- If the tune up goes well, you can tighten your goal or hold steady with more confidence.
- If it feels rough, adjust your marathon pace target and focus on finishing strong and healthy.
- Either way, the half marathon is information, not a verdict on your season.