20-Week Chicago Marathon Training Plan

Chicago, ILOctober 11, 2026

Start around May 24, 2026. The calendar below gives each phase a real date, then the course guidance shows where to make the build specific to Chicago Marathon.

Chicago is the flat, fast American major: a single loop out of Grant Park through more than two dozen neighborhoods, wall-to-wall crowds, and a course where world records have fallen. If you have a time goal, this is a course that will let you chase it.

Race day
October 11, 2026
Start window
May 24, 2026
Runway
20 weeks
Course
a flat loop through 29 neighborhoods
Plan choice
Current training

Does this window fit your starting point?

Use the longer window to make the early build calmer, not to add five months of hard training. The plan should begin close to your current load, hold most running easy, and delay the biggest race-specific work until the middle of the cycle.

  • You want a longer foundation phase before marathon-specific training.
  • Your current mileage is steady but below the load you expect to carry later.
  • You prefer gradual long-run growth with regular step-back weeks.
  • You can sustain a five-month routine without turning every week into a peak week.

The 20-week Chicago Marathon calendar

These dates define the job of each phase. Your current mileage, recent longest run, experience, goal, and available days still decide the actual workouts inside them.

Foundation

Weeks 1–6

May 25, 2026–Jul 5, 2026

Set the routine, grow easy volume gradually, and finish each week with enough control to repeat it.

Build

Weeks 7–13

Jul 6, 2026–Aug 23, 2026

Extend the long run, introduce race-specific terrain, and keep recovery weeks on the calendar.

Peak

Weeks 14–17

Aug 24, 2026–Sep 20, 2026

Complete the most demanding race rehearsals and settle fueling, pacing, shoes, and clothing before taper begins.

Taper

Weeks 18–20

Sep 21, 2026–Oct 11, 2026

Reduce the load, keep familiar running in the week, and let the work from the previous four months show up on race day.

Make the window specific to Chicago Marathon.

Build general durability first. Add the race's hills, flat sustained running, downhill exposure, heat, or humidity in layers after the weekly rhythm is stable, then make the final long runs the most course-specific.

Read the full race guide

How to train for Chicago

Flat and fast means rhythm. Chicago rewards long runs with sustained goal-pace segments; the ability to lock a number and hold it for an hour-plus is the entire skill. Stride’s time-goal builds put that work in your week at the right dose for your volume history.

It’s an October race, so you’ll build through summer heat and race in (usually) cool air, though Chicago Octobers have served up everything from 35°F to 80°F. Train by effort, plan clothing for a range, and rehearse fueling at goal pace, because a flat course lets you run fast enough to make your stomach the limiter.

Let your current training decide the actual plan.

Current mileage, recent longest run, marathon experience, goal, and available days determine which plans rank first. After you choose and subscribe, Stride dates every workout through October 11, 2026.

Build My Plan

20-week Chicago Marathon plan questions, answered.

When should I start a 20-week Chicago Marathon plan?

The 2026 Chicago Marathon is scheduled for October 11, 2026, so the 20-week window opens around May 24, 2026. Treat that as the outside edge of the window, then line week one up with the plan's normal weekly rhythm.

Is a 20-week plan long enough for the Chicago Marathon?

Use the longer window to make the early build calmer, not to add five months of hard training. The plan should begin close to your current load, hold most running easy, and delay the biggest race-specific work until the middle of the cycle. The course does not change the opening load you can handle, so choose from your current mileage and recent longest run before adding race-specific terrain.

How should I prepare for the Chicago Marathon course in 20 weeks?

Build general durability first. Add the race's hills, flat sustained running, downhill exposure, heat, or humidity in layers after the weekly rhythm is stable, then make the final long runs the most course-specific. Flat and fast means rhythm. Chicago rewards long runs with sustained goal-pace segments; the ability to lock a number and hold it for an hour-plus is the entire skill. Stride’s time-goal builds put that work in your week at the right dose for your volume history.

What if the 20-week Chicago Marathon window has already started?

Do not double weeks or cram missed mileage into the remaining calendar. Use your current mileage, recent longest run, experience, goal, and available days to choose a plan that can enter at an appropriate point while preserving the taper.

How long do I need to train for the Chicago Marathon?

Most Stride marathon plans run 12 to 20 weeks depending on your base and goal. Get matched in the app and every week from today to race day in Grant Park gets mapped, long runs, step-back weeks, and taper included.

Is Chicago a good marathon for a PR or a BQ?

One of the best in the world. The course is flat, the crowds carry you, and October in Chicago is usually cool. If you pace evenly and your buildup included real goal-pace work, Chicago will give you everything your fitness has.

Put the 20-week window against your actual race.

Each page counts back from race day, maps the 4 phases to real dates, and applies the window to that course and its typical conditions.