Nothing the uncertain Finnish weather can produce on Sunday will deter Justin Gatlin in his quest for a world 100 metres title to add to the Olympic gold he won in Athens last year.
On Saturday morning the American promised a world record if necessary to win the title. After the evening's second round as temperatures dropped sharply and rain began to fall the American was even more upbeat.
"Rain, sleet, snow? It doesn't matter," he said. "I'm going to come out blazing."
The day's five finals begin with the women's 20 km walk in the morning and conclude with the men's 100 metres at night.
In between the men's discus and women's triple jump finals will be concluded while defending champion Carolina Kluft and the 1999 gold medallist Eunice Barber fight for the heptathlon title.
An American clean sweep is possible if not probable in the 100 metres with Olympic 200 metres champion Shawn Crawford and Leonard Scott coming safely through the first two rounds.
Defending champion Kim Collins did little to dispel the impression that his win in Paris two years ago will remain his only major victory by sneaking in to the semi-finals as a fastest loser.
In the absence of injured world record holder Asafa Powell, Frenchman Ronald Pognon is a medal prospect after dipping under 10 seconds for the first time this year.
The heptathlon has developed into a battle royal after a day of fluctuating fortunes on Saturday.
Kluft, who twisted her left ankle in training on Friday, failed three times at 1.85 metres in the high jump, well below her lifetime best of 1.94.
Meanwhile Barber, who missed the Olympics through injury, set a season's best of 12.94 seconds in the hurdles and equalled her lifetime best in the high jump with a clearance of 1.91 metres.
Kluft bounced back in the afternoon session with a personal best of 15.02 metres in the shot put, her weakest event, and cut Barber's margin to two points by clocking 23.70 in the 200 metres.
"It's going to be a big, big show," said Barber. "I have to jump well, throw well and run well."