Several matches at the competition will be played in the early afternoon in tropical venues such as Natal, Recife and Salvador, as well as the dry and dusty capital Brasilia.
The kick-off times were finalised by FIFA on Thursday. With most of Brazil three hours behind GMT, the afternoon times are favourable for European television viewers who will be able to watch matches in their evening.
FIFA secretary general Jerome Valcke, clearly exasperated at constant criticism of the tournament's organisation, said there had been little room for manoeuvre.
He also dismissed talk that Brazil, who will not have to play any early or mid-afternoon games, had been favoured.
"I don't even imagine why and how you could think we are making decisions thinking about the television and not thinking about the health of the players," Valcke told reporters following a question from a Brazilian journalist.
"The first thing we need is a good World Cup and to have a good World Cup we must make sure we have the best of football and to have the best of football, we need the best teams and the best game.
"Every decision we make takes into consideration the health of the players."
Valcke said that part of the problem had been caused by local organisers wanting teams to move around between venues in different parts of the country,
"We have made a decision to play in all Brazil because that was the request of Brazil," he said.
"You have a country which is not a small country, it is a continent, where it can be two degrees and 26 degrees at the same time on the same day.
"Then you have to take these teams around the country because it was also a decision not to play in just in one region of the country but to travel all around the country to give all Brazilians the chance to enjoy Germany, Italy and the other top teams."
Valcke added that, whatever they did, World Cup organisers were criticised.
"The match schedule was wrong, the kick-off times are wrong," he said with an air of frustration.
"We have discussed with our medical department, we have been discussing with our local organising committee and finally also with football specialists and they all agree that these kick-off times, wherever we put them, from south of the country to the north, are still at a time where players can play without any problem."
Valcke, speaking after FIFA's Executive Committee meeting, acknowledged Brazil had been fortunate.
"The match schedule has not been organised just for Brazil to win this World Cup, it is true they are lucky and playing in very good conditions," he said.
FIFA president Sepp Blatter said players would adapt.
"The history of football has shown that great players can play in all conditions," he said. "In Mexico in 1970 and 1986, we played at high noon, at 2,400 metres and the quality of the game did not suffer.
"You know that in difficult conditions, you can stop the game, you can cool down, and have drinks. You will remember 25 years ago, the referees said it was forbidden to drink water during the matches, and now all that has been changed because we want to take care of the health of the players."
"The actors are the players, we need the players."
This week, UEFA boss Michel Platini again called for a winter World Cup in Qatar in 2022 because of worries over the heat.
- Jerome Valcke