[Eleven-Cities skating marathon and the windchill factor].

The weather conditions during the 15th Eleven Cities ice skating marathon (200 kilometers) in Friesland (the Netherlands) on 4 January, 1997, were better than predicted. For measurement of the windchill factor the Steadman scale is preferred to the Siple and Passel scale. For ice skaters the windchill factor is lower than for the spectators, due to the drag effect.