Historically and in 2026, the two hottest months in London are July and August. July typically holds the title for the highest average temperatures, with daytime highs often reaching between 22°C and 25°C (72°F to 77°F), though "heatwave" events in recent years have seen temperatures spike well above 35°C (95°F). August follows closely, offering similar "temperate summer" warmth and the most consistent sunshine. These months are considered the "gold standard" for outdoor events like the Wimbledon Championships and various music festivals. However, because London's humidity can make 25°C feel much warmer, and many historic buildings lack central air conditioning, the heat can be quite noticeable for those unaccustomed to urban "heat island" effects. Travelers in July and August should be prepared for occasional thunderstorms, which are the city's natural way of breaking the humidity. By late September, the temperatures begin a sharp decline, making the mid-summer window the premier, albeit most crowded, time to experience the British capital in its warmest and most vibrant state.