The decision to hold the World Athletics Championships in the Middle East presented organisational challenges due to the hot and humid climate in Doha in September and October. In previous years the World Championships had mostly qualifying competitions in morning sessions and finals mostly in afternoon sessions. Weather conditions meant that traditional arrangement was not workable and in Doha the schedule was redesigned to have a "pre-session" in the afternoon and a "main session" in the evening.[27] The Khalifa International Stadium used an open-air conditioning system to bring the temperature of the stadium to below 25 °C (77 °F), which was a world first for a stadium.[28][29]