Four matches are set for Saturday during the third day of the 2014 World Cup in Brazil.
The matches in Fortaleza and Manaus are most likely to be impacted by the weather.
Numerous showers are expected in Fortaleza with possible downpours during the match between Uruguay and Costa Rica.
Any heavy downpour can quickly change field conditions, forcing teams to change their style of play. A warm and muggy air mass will also push the athletes to their limits during the match as the combination of warm air and high dewpoints will make it feel like temperatures are in the lower 90s F (33-34 C).
A brief shower is possible during the night game between Japan and Ivory Coast in Recife; however, any impacts are expected to be minor.
The heat will be a big issue for England and Italy as they face off in the Amazon city of Manaus.
According to Accuweather.com Meteorologist Steve Travis, "While the weather in Manaus will be tolerable relative to normal temperatures in the Amazon, the combination of temperatures in the 80s and dew points near 70 degrees will feel quite oppressive for the teams of Italy and England, both of whom reside in more temperate climates."
The fourth match, taking place in Belo Horizonte, will feature more comfortable temperatures and dry conditions.