Over the past 10 years, Helsinki Marathon runners have faced temperatures ranging from 15\u00b0C (59\u00b0F) on cooler years to 22\u00b0C (71\u00b0F) in warmer editions. The median temperature of 18\u00b0C (65\u00b0F) puts this race in the challenging category for running conditions.
Wind speeds average 14 km/h during race hours, with peak gusts reaching 21 km/h in challenging years. Humidity sits around 73%, and there is a 10% chance of rain on race day.
These conditions translate to an estimated pace impact of +5.2% compared to ideal running conditions. For a 4-hour marathoner, that means roughly 12 minutes slower than a perfect-weather day.