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Spring marathons peak February through April; fall marathons dominate September through November. Summer owns the 5K and 10K circuit, while winter brings trail races and obstacle events. Knowing when races cluster in your region lets you build a training plan that peaks when it matters—not three weeks too early or too late.
Spring Marathon Season (February–April)
Cool, stable temperatures make February through April the fastest window for 26.2-mile efforts. Boston (April), London (April), and Tokyo (March) set the marquee schedule. Regional spring marathons fill 8–12 weeks before race day, with entry deadlines often closing in December or January—so if you’re eyeing a spring race, register by mid-January.
Your training block starts in November or December: 16–20 weeks to build base fitness and hit the start line sharp, not exhausted.
Boston Marathon Qualifier Windows
Boston qualifying standards reset each calendar year and vary by age group. A 40-year-old male needs sub-2:50; a 50-year-old female needs sub-3:20. Run your qualifier between January 1 and September 30, then submit proof by October 1 for the following April’s race. Target a spring or early-summer qualifier so you have time for a second attempt if you miss the cut.
Spring Training Timeline
Count back 18–20 weeks from race day and mark these checkpoints:
- Weeks 1–6: Build to 30–35 miles per week
- Weeks 7–12: Add tempo runs; long runs reach 12–16 miles
- Weeks 13–16: Peak with 18–20 mile long runs
- Weeks 17–20: Taper—cut volume 20–30% while keeping pace work intact
Summer 5K and 10K Circuit (May–August)
May through August is peak short-race season. Road races, track meets, and summer series run almost every weekend in most metro areas. Entry fees land between $25–$50, and most local 5Ks accept registrations the morning of the race.
If you’re building toward a fall marathon, use summer 5K and 10K races as controlled tempo efforts—one race every 4–6 weeks keeps your aerobic system sharp without wrecking your long-run progression. Keep long runs under 12 miles in July and August; save 16-mile-plus efforts for September.
Track Season (June–August)
Local track meets run weekly in most regions from June through August. Entry costs $5–$15. Racing 5K or 10K on a track teaches pacing discipline and produces accurate times in controlled conditions—useful data before you commit to a fall road marathon.
Summer Training Volume
Runners not targeting a fall marathon should maintain 25–35 miles per week with one long run of 8–12 miles. Heat adds physiological load, so reduce pace by 20–30 seconds per mile when temperatures exceed 75°F and humidity tops 60%. Run before 6 a.m. or after 7 p.m. to avoid peak heat.
Fall Marathon Season (September–November)
Fall rivals spring for both race volume and fast times. Chicago (October), New York City (November), and Marine Corps (October) anchor the calendar. These races use lottery or time-based entry and sell out within hours of opening—check race websites each November for the following fall’s entry window. Regional fall marathons (under 5,000 runners) typically fill 8–10 weeks ahead; register by August to be safe.
Your training block starts in June or July. Summer 5K and 10K races serve as speed-work checkpoints before you shift to marathon-pace long runs in August and September.
Fall Training Timeline
- Weeks 1–6: Build to 35–40 miles per week
- Weeks 7–12: Long runs reach 14–18 miles; add marathon-pace segments
- Weeks 13–16: Peak with 18–22 mile long runs
- Weeks 17–20: Taper—cut volume 20–30%, keep pace work sharp
Heat and Humidity Strategies
July and August training happens in peak heat. Reduce pace by 20–30 seconds per mile on days above 75°F; focus on effort, not splits. Hydrate 16–20 ounces every 20 minutes on runs over 60 minutes. These aren’t optional adjustments—heat stress at high training volume is a direct path to overtraining.
Winter Trail and Obstacle Racing (December–February)
Winter suits runners recovering from fall marathons. A trail 5K or 10K in December keeps you active without the impact load of road training. Trail races range from 5K to 50+ miles and fill 4–8 weeks ahead. Obstacle races—Tough Mudder, Spartan Race—run year-round but concentrate November through January.
Targeting a winter ultramarathon? Start training 20–24 weeks out. Plan for 30–40 miles per week with one 15–30 mile long run every two weeks. Lower weekly mileage than road marathon prep, but the long-run demands are higher.
Ultramarathon Calendar
50K and 50-mile races cluster September through April. Western States 100 (June) is lottery-based and highly competitive; Badwater 135 (July) is the most extreme desert race on the domestic calendar. Most regional ultras accept entries 8–12 weeks ahead. A 50K training block requires 40–50 miles per week with one 20–30 mile run every two weeks for roughly six months.
Qualifying Races and Championship Windows
U.S. Olympic Marathon Trials (next: 2028) requires sub-2:19 for men and sub-2:45 for women, run within a specific qualifying window set by USA Track & Field. NCAA and high school cross-country seasons run September through November, with state and national championships in November and December. Track and field qualifying windows for national championships close in June (outdoor) and February (indoor).
Register for spring races by January and fall races by August to avoid sold-out fields and secure your preferred start time.
Regional Race Calendars and Registration Tips
Running USA (runningusa.org), Active.com, and local running clubs publish regional calendars. Build a simple spreadsheet: 3–5 target races, their registration deadlines, and the date you need to start training. Work backward from race day to set your base-building start date.
Entry Fee Ranges
| Race Type | Typical Entry Fee |
|---|---|
| Local 5K | $25–$50 |
| Half marathon | $50–$120 |
| Marathon (regional) | $100–$250 |
| Marathon (major city) | $200–$300 |
| Ultramarathon | $150–$400 |
| Trail race | $60–$200 |
| Obstacle race | $80–$150 |
Training Plan Alignment
New to racing? Start with a beginner 5K training plan—expect 8–12 weeks of focused work before your first race. Before committing to a full marathon block, run a 12-week half marathon plan first. The half marathon reveals pacing gaps and injury risk before you’re 18 weeks deep in marathon prep.
Building Your Personal Race Calendar
One A-race per season—the one you’ll peak for. Schedule B-races 8–12 weeks before your A-race to test fitness under pressure. Schedule C-races 4–6 weeks out as speed work or low-stakes efforts. This structure prevents burnout and keeps training purposeful.
A sample 2024 calendar: January 5K (C-race) → March half marathon (B-race) → April marathon (A-race) → June 10K (C-race) → August 5K (speed work) → October marathon (A-race) → December trail 5K (recovery).
Allow 2–3 weeks of easy running between races when racing every 4–6 weeks. DNF rates spike when runners toe the line fatigued—skipping a race is always cheaper than an injury that wipes out the next training block.
Frequently asked questions
When should I register for a marathon?
Register 8–12 weeks before race day for regional marathons under 5,000 runners. For Boston, Chicago, or NYC, register the moment entry opens—spots fill within hours to days. Check race websites in August for fall marathons and November for spring marathons.
Can I race a 5K while training for a marathon?
Yes. A 5K every 4–6 weeks during marathon training functions as a tempo workout and fitness check. Keep 5K races at least 10–12 weeks before your marathon so they don’t cut into peak training weeks. Treat them as hard efforts, not all-out races.
What’s the best time to run a Boston Marathon qualifying race?
Run your qualifier between January 1 and September 30. Spring and early summer (March–June) give you time for a second attempt if you miss the standard. Submit proof by October 1 for entry into the following April’s race.
How many weeks before a marathon should I start training?
Start 16–20 weeks out. Beginners should use 20 weeks; experienced runners can work with 16. Plan for 6–8 weeks of base building, 8–10 weeks of speed and long-run work, then a 4-week taper.
When do summer 5K and 10K races fill up?
Local summer 5Ks rarely fill—most accept entries race morning. Popular summer series or track meets may close 2–4 weeks ahead. Check Active.com or your local running club calendar 6–8 weeks before the race you want.
Casey is a certified strength coach and trail runner who tests gear by breaking it.
