River Thames Half Marathon

River Thames Half Marathon 2026 Course Analysis

River Thames Half Marathon is a half marathon held in Walton-on-Thames, United Kingdom, scheduled for Sunday 28 June 2026. The course is run on mixed surface with 23m of total elevation gain, reaching a maximum altitude of 22m above sea level. For registration and full race details, visit the official River Thames Half Marathon website.

Elevation Profile

This is a very flat course with only 23m of total elevation gain across the full distance. The course ranges from 7m to 22m above sea level — a 15m elevation range that makes it one of the flatter races available. Runners targeting a personal best will appreciate the minimal climbing.

Expected Race Day Weather

Based on historical weather data for June, the expected race day conditions are as follows. Near-ideal running temperatures are expected, ranging from 5°C to 11°C. This temperature range is widely considered optimal for marathon performance, allowing efficient heat dissipation without cold-related issues. There is a high chance of rain (70%). Runners should prepare for wet conditions, including appropriate footwear and clothing choices.

Surface Type: Mixed

River Thames Half Marathon features a mixed-surface course, combining sections of road with unpaved terrain such as gravel paths, parkland, or boardwalks. Mixed courses add variety but also introduce some unpredictability in footing. Runners should expect slightly slower times compared to a pure road marathon, and road-trail hybrid shoes may be the best footwear option.

How Difficult Is River Thames Half Marathon?

Our difficulty rating for River Thames Half Marathon is calculated using a model that combines elevation gain, temperature impact, and surface type. Use the difficulty calculator above to enter your target finish time and see exactly how many minutes this course would add or subtract compared to a perfectly flat, cool, road-based half marathon. Faster runners and slower runners are affected differently by the same course conditions, so the difficulty is personalised to your pace.

Looking for an easier marathon or a tougher challenge? You can also compare River Thames Half Marathon against other half marathons to find the right race for your goals.