The best time to walk Hadrian’s Wall path is between May and October, when average temperatures are 10.5 °C to 15 °C. See the chart below for average temperatures and rainfall of the Hadrian’s Wall route.   With 100,000 visitors per year, the Hadrian’s Wall route is well worn and muddy when wet in patches. Therefore, it many walkers choose to give the trail time to recover over winter.   I have run Hadrian’s Wall in August, when it gets popular with tourists and extremely hot, with minimal sun cover.