How Brazil's climate will affect the World Cup

Italian manager Cesare Prandelli uttered what might become the mantra of the 2014 World Cup after watching his team struggle to a 4-3 victory over Japan at Arena Pernambuco in Recife during the 2013 Confederations Cup.

“The humidity and heat is unbearable, so we have to figure out how to deal with it,” Prandelli told reporters, lending a first-hand account to concerns the tropical heat and humidity of Brazil’s northern stadium locations will become the toughest opponent at the tournament.

Recife averages 83.8-degree highs in June, with humidity hovering around 85 percent. Other host cities like Manaus, Fortaleza and Cuiaba will provide similar meteorological challenges, especially for matches starting at 1 p.m. local time.

[Data: weatherbase.com]

Italy will return to Recife to face Costa Rica in an early afternoon start on June 20 and the USA faces Germany there in the same time slot six days later, while one Round of 16 match is scheduled for a 1 p.m. local start at Fortaleza.

Seven other early matches were changed after complaints from FIFPro, the international football players' union, but the Brazilian federation of professional athletes is still suing to change all 24 remaining 1 p.m. local starts or at least allow extra breaks to let the players hydrate in order to mitigate the intense heat.

FIFA released a statement in response:

FIFA's medical team is always monitoring carefully all venues during any FIFA competition to protect the players' health. Cooling breaks will be considered on a match-by-match basis for the 64 matches. Official and mandatory cooling breaks will not be pre-established. Rather, climate conditions will be evaluated prior to each match by the FIFA venue medical officer.

FIFPro previously accused FIFA of putting television concerns ahead of player safety. 1 p.m. local starts provide an ideal late-afternoon broadcast in Europe, while evening starts translate to around midnight.

The possibility of an El Nino event raising temperatures during the tournament also looms, raising the specter of all daytime games becoming hazardous - even those in the more temperate southern reigon. Some climate scientists place the likelihood of such an event over 50 percent, and they believe it would "increase the risk of uncomfortably hot and dry conditions in Brazil during June and July."

Extreme heat can completely change the pace and quality of a match, as players become dehydrated and fatigued much quicker than normally. Players run shorter distances in high temperatures and sweat through nearly twice as much water, according to soccerperformance.org.

An increase in temperature raises the internal air pressure and elasticity of a soccer ball, which could lead to erratic bounces and make long passes tougher to corral. 

Playing in the midday sun will also provide distinct advantages for certain teams, depending on the color of their kit. Dark jerseys will absorb more heat, while any team playing in white jerseys will have the upper hand. This could go a long way towards evening the playing field between a powerhouse like Italy and 34th-ranked Costa Rica, if Costa Rica is in white and the Azzurri wear blue.

Many teams are attempting to acclimatize their players as part of their training for the tournament. England manager Roy Hodgson has his players practicing in three layers of clothing to simulate the suffocating embrace of Amazon humidity. The United States team is practicing twice per day at Stanford University in California, running endurance sprints in temperatures as high as 95 degrees.

"This will be a World Cup where teams that do well will suffer," United States midfielder Michael Bradley told ESPN during practice. "We want to be the team that can suffer the most."