What is the fastest that the tail wind speed can be for an outdoor 100 metre dash result to count as a record?

The 100 metres, or 100 metre dash, is a sprint race in track and field competitions. The shortest common outdoor running distance, it is one of the most popular and prestigious events in the sport of athletics. It has been contested at the Summer Olympics since 1896 for men and since 1928 for women.

Climatic conditions, in particular air resistance, can affect performances in the 100 m. A strong head wind is very detrimental to performance, while a tail wind can improve performances significantly. For this reason, a maximum tail wind of 2.0 m/s is allowed for a 100 m performance to be considered eligible for records, or "wind legal".

The reigning 100 m Olympic champion is often named "the fastest man in the world". The World Championships 100 metres has been contested since 1983. Americans Justin Gatlin and Tori Bowie are the reigning world champions; Usain Bolt and Elaine Thompson are the Olympic champions in the men's and women's 100 metres, respectively.

The 10-second barrier has historically been a barometer of fast men's performances, while the best female sprinters take eleven seconds or less to complete the race. The current men's world record is 9.58 seconds, set by Jamaica's Usain Bolt in 2009, while the women's world record of 10.49 seconds set by American Florence Griffith-Joyner in 1988 remains unbroken.