What is the maximum allowable tailwind for an athletics 100-metre performance to count as a world record?

The maximum allowable tailwind for an athletics 100-metre performance to count as a world record is 2.0 metres per second.

World Athletics uses wind readings to distinguish performances assisted by legal conditions from those receiving excessive help. In the 100 metres, 200 metres and long jump, a tailwind greater than 2.0 metres per second prevents a mark from being accepted for record purposes. The wind gauge is positioned and timed according to technical rules.

A wind reading above the limit does not erase the athlete's performance or make the race unofficial. It means the result is wind-assisted and cannot qualify for certain records. Headwinds can slow athletes, while crosswinds may affect competitors differently without creating the same direct tailwind assistance. Indoor races generally do not have outdoor wind readings because the track is enclosed.