Over the past 10 years, Nairobi Marathon runners have faced temperatures ranging from 16\u00b0C (61\u00b0F) on cooler years to 27\u00b0C (81\u00b0F) in warmer editions. The median temperature of 22\u00b0C (72\u00b0F) puts this race in the challenging category for running conditions.
Wind speeds average 10 km/h during race hours, with peak gusts reaching 15 km/h in challenging years. Humidity sits around 62%, and there is a 60% chance of rain on race day.
These conditions translate to an estimated pace impact of +6.5% compared to ideal running conditions. For a 4-hour marathoner, that means roughly 16 minutes slower than a perfect-weather day.