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Boston Marathon

Monday, April 19, 2027 · Boston, USA

Updated May 2026

Unidirectional point-to-point with severe net negative elevation drop. The first half's 1,275ft descent destroys quadriceps via eccentric loading; the Newton Hills at miles 16-21 — including Heartbreak Hill — arrive precisely when glycogen is depleted.

Kenyan Running Difficulty Index10.0 / 10How the course actually runs
Kenyan Running Elite Field Index9.5 / 10How deep the field around you is

The score breakdown

The Kenyan Running Difficulty Index combines four weighted factors. The heaviest weight (35%) is on Tactical Brutality. That is what a Kenyan coach watches first: where the field actually blows up.

Topographic Stress (30% weight)12.1 / 30
Atmospheric Stress (20% weight)14.5 / 20
Course Friction (15% weight)4.5 / 15
Tactical Brutality (35% weight)30.0 / 35
  • Highest KR Difficulty in the set.
  • Atmospheric Stress is high due to historic weather variability (38°F to 87°F across last decade).
  • Tactical Brutality near cap because the combination of quad damage + Newton Hills + late-stage timing punishes most pacing strategies.

Score confidence: preliminary. Computed from public course, weather, and prize data; calibration against 5K split data and coach review is in progress.

Course profile

Elevation gain
248m / 815ft
Elevation loss
388m / 1275ft
Highest point
141m
Surface
paved smooth
Late-stage climbs (after mile 18)
Heartbreak Hill at miles 20-21 (after preceding rollers from mile 16). Final 5 miles roll downward on damaged quads.
Profile notes
Opening 4 miles drop 267ft (eccentric loading). Newton Hills mile 16-21. Net downhill but mathematically NOT a fast course due to quad damage timing.

Race day

Date
Monday, April 19, 2027
Field size
32,000
Entry
Competitive time standards by age/gender. From 2027 registrations: qualifying times from courses with net downhill drop ≥1,500ft incur an index penalty (+5 minutes for 1,500–2,999ft drops; +10 minutes for 3,000–5,999ft drops); courses dropping ≥6,000ft are disallowed.
Time limit
6 hours

Weather (historical)

Median temp
14.5°C
Temp range
3°C to 30°C
Humidity
72% at start
Wind
Variable; recent editions have shown 15 km/h E/NE headwind
Notable weather events
  • 2018: severe rain, snow, upper-30s temperatures
  • 2012: intense heat reaching 87°F

Prize money

Total purse
$1,284,500 (2026/2027)
Winner
$150K
Course record bonus
$50K
Notes
Course is ineligible for World Record status due to net downhill exceeding regulatory limits. Highest total purse among the listed races.

Course records

Men's record2:01:52John Korir (KEN), 2026
Women's record2:17:22Sharon Lokedi (KEN), 2025

Recent winners

Top East African winners (Kenya, Ethiopia, Eritrea, Uganda) across the last 10 verified editions: 9 men, 9 women.

YearMen's winnerTimeWomen's winnerTime
2026John Korir (KEN)2:01:52Sharon Lokedi (KEN)2:18:51
2025John Korir (KEN)2:04:45Sharon Lokedi (KEN)2:17:22
2024Sisay Lemma (ETH)2:06:17Hellen Obiri (KEN)2:22:37
2023Evans Chebet (KEN)2:05:54Hellen Obiri (KEN)2:21:38
2022Evans Chebet (KEN)2:06:51Peres Jepchirchir (KEN)2:21:01
2021Benson Kipruto (KEN)2:09:51Edna Kiplagat (KEN)2:25:09
2019Lawrence Cherono (KEN)2:07:57Worknesh Degefa (ETH)2:23:31
2018Yuki Kawauchi (JPN)2:15:58Desiree Linden (USA)2:39:54
2017Geoffrey Kirui (KEN)2:09:37Edna Kiplagat (KEN)2:21:52
2016Lemi Berhanu Hayle (ETH)2:12:45Atsede Bayisa (ETH)2:29:19

Training for Boston Marathon?

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