Semi Marathon Nantes

Semi Marathon Nantes 2025 Course Analysis

Semi Marathon Nantes is a full marathon held in Nantes, France, scheduled for Saturday 26 April 2025. The course is run on road surface with 361m of total elevation gain, reaching a maximum altitude of 125m above sea level. For registration and full race details, visit the official Semi Marathon Nantes website.

Elevation Profile

This is a hilly course with 361m of total elevation gain. The route climbs from -15m to as high as 125m above sea level — a substantial 140m elevation range. Runners should train on hills and plan for a more conservative pacing strategy, especially on the climbs.

Expected Race Day Weather

Based on historical weather data for April, the expected race day conditions are as follows. Near-ideal running temperatures are expected, ranging from 11°C to 15°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 (85%). Runners should prepare for wet conditions, including appropriate footwear and clothing choices.

Surface Type: Road

Semi Marathon Nantes 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 Semi Marathon Nantes?

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