There have been growing calls to move the tournament to the winter to avoid the sweltering desert heat which is expected to exceed 40 degrees Celsius (104 degrees Fahrenheit) in June and July. UEFA President Michel Platini is one of those requesting the switch and Blatter understands why.
"It has been presented in the bid documents and in the presentation they made here in Zurich that there is a system that the stadia can be presented in, let's say, an atmosphere where it will not be too hot, too warm. But the World Cup is not only played in the stadia," Blatter said. "The World Cup is also outside of the stadia so it is a question mark."
Blatter said a final decision on a summer or winter World Cup needed to be taken after the 2014 final in Brazil.
In a wide-ranging interview on "Special Report" broadcast Monday on Sky Sports News, football's most powerful man confirmed he would be standing down in 2015 from the position he has held since 1998.
He says there is a "good possibility" Platini will be his successor but remains unconvinced that the former France midfielder is keen on the role.
Blatter also reiterated his belief in introducing points deductions for incidents of racist abuse, which he believes is the one of the biggest scourges in football along with match-fixing.
"Our committee at FIFA has given a sentence to play without spectators — this is one of the solutions, (but) I think a more radical solution would be deduction of points," Blatter said. "Deduction of points would have a better impact on that than any other sanction.
"I think we can never do enough to eradicate all the racism in football," added Blatter, who said he was thinking of holding a summit "with all the actors concerning discrimination and racism."