The official wind reading for Bolt’s 9.58-second 100 metres world record was +0.9 m/s.
Bolt set the record in the final of the 2009 World Championships in Berlin on 16 August 2009. The legal tailwind helped the sprinters, but it was well below the 2.0 m/s limit required for a performance to qualify as wind-assisted under athletics rules.
His 9.58 seconds lowered his own previous world record of 9.69, set at the 2008 Beijing Olympics, by 0.11 seconds. Tyson Gay finished second in 9.71, while Asafa Powell took bronze in 9.84. The margin and speed made the race one of the most extraordinary finals in sprint history.
A common mix-up is confusing this result with Bolt’s 200-metre world record at the same championships. That 19.19-second run came four days later and was recorded with a headwind of −0.3 m/s, not the +0.9 m/s measured for the 100 metres.