Clarendon Marathon

Clarendon Marathon 2026 Course Analysis

Clarendon Marathon is a full marathon held in Winchester, United Kingdom, scheduled for Sunday 31 May 2026. The course is run on road surface with 794m of total elevation gain, reaching a maximum altitude of 170m above sea level. For registration and full race details, visit the official Clarendon Marathon website.

Elevation Profile

This is a very challenging course with 794m of total elevation gain — significantly more than the average road marathon. The route ranges from 29m to 170m above sea level (141m range). Hill training is essential, and runners should expect a significantly slower time compared to a flat course.

Expected Race Day Weather

Based on historical weather data for May, the expected race day conditions are as follows. Near-ideal running temperatures are expected, ranging from 10°C to 16°C. This temperature range is widely considered optimal for marathon performance, allowing efficient heat dissipation without cold-related issues. There is a low chance of rain (3%), so dry conditions are likely.

Surface Type: Road

Clarendon Marathon is run on road surfaces, which provide the fastest and most predictable conditions for marathon running. Road courses allow for consistent pacing and are typically the best choice for runners targeting a personal best time.

How Difficult Is Clarendon Marathon?

Our difficulty rating for Clarendon 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 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 Clarendon Marathon against other marathons to find the right race for your goals.