
Kielder, United Kingdom · Sunday 5 October 2025
The Kielder Half Marathon takes place in Kielder Water and Forest Park, located in the Northumberland National Park in northern England. Known for its remote and tranquil setting, the course takes runners through dense woodlands, along the shore of Kielder Water, and over rolling hills. The route offers spectacular views of the Kielder Reservoir and the surrounding mountains, providing a truly scenic and peaceful environment for runners. The course is challenging, with a series of inclines and t
Adjusted Time
2:24:09
Time difference: +39.2 minutes compared to a flat, road, temperate course.
Kielder Half Marathon is a half marathon held in Kielder, United Kingdom, scheduled for Sunday 5 October 2025. The course is run on trail surface with 252m of total elevation gain, reaching a maximum altitude of 250m above sea level. For registration and full race details, visit the official Kielder Half Marathon website.
With 252m of elevation gain, this is a moderately undulating course. The route ranges from 192m to 250m above sea level (58m total range). While not completely flat, the elevation changes are manageable for most runners and shouldn't significantly impact pacing strategy.
Based on historical weather data for October, the expected race day conditions are as follows. Near-ideal running temperatures are expected, ranging from 8°C to 12°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 (55%). Runners should prepare for wet conditions, including appropriate footwear and clothing choices.
Kielder Half Marathon is a trail race, meaning the course includes unpaved surfaces such as dirt, gravel, or forest paths. Trail surfaces are inherently slower than road courses due to uneven footing, technical sections, and often steeper gradients. Trail-specific shoes with good grip are recommended, and runners should expect a finish time 10-20% slower than their equivalent road marathon time.
Our difficulty rating for Kielder 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 Kielder Half Marathon against other half marathons to find the right race for your goals.
Bungay, United Kingdom
Southampton, United Kingdom
Omagh, United Kingdom
Bakewell, United Kingdom
Boston, United Kingdom
Ashford, United Kingdom