Over the past 10 years, Tokyo Marathon runners have faced temperatures ranging from 4\u00b0C (40\u00b0F) on cooler years to 17\u00b0C (63\u00b0F) in warmer editions. The median temperature of 11\u00b0C (52\u00b0F) puts this race in the neutral category for running conditions.
Wind speeds average 14 km/h during race hours, with peak gusts reaching 30 km/h in challenging years. Humidity sits around 59%, and there is a 20% chance of rain on race day.
These conditions translate to an estimated pace impact of +2.5% compared to ideal running conditions. For a 4-hour marathoner, that means roughly 6 minutes slower than a perfect-weather day.