Sweltering, oppressive, stifling.Call it what you want, this World Cup is going to be hot, with a sizeable chunk of games set to be played above 90F (32C).It is likely to be the warmest edition since, well, the last time it was held in North America, when the U.S. hosted it in 1994. That World Cup, with more than 80 per cent of matches played before 5pm local time — usually under a baking afternoon sun — became notorious for its draining conditions. A memorable example was Mexico’s 2-1 victory over the Republic of Ireland in Orlando, where temperatures soared to 117F at pitch level.There is little reason to think this tournament will be much different.Last summer, FIFA hosted the Club World Cup in the U.S., a competition that served as something of a dry run for the upcoming showpiece. The graphic below, using weather data sourced from Visual Crossing, shows it was warmer than each of the last four World Cups.But only five of the stadiums used in that tournament are hosting matches at this World Cup, which is also spread across Mexico and Canada. To build a more complete picture, The Athletic analysed 10 years of hourly weather data for each fixture, using the scheduled kick-off time, plus an hour either side, across a seven-day window around the match date.As an example, for the quarter-final in Kansas City on July 11 at 8pm local time, that meant looking at what the weather was like between 7pm and 9pm from July 8 to July 14 in each of the past 10 years.The results are shown below, with AT&T Stadium in Dallas topping the temperature charts at an estimated average of 90F (32C), followed closely south of the border by Estadio BBVA in Monterrey. The mercury is expected to peak on July 14, when AT&T Stadium hosts a 2pm semi-final at an estimated 93F (34C). But Dallas is one of three venues, along with Atlanta and Houston, that will operate with closed roofs and air conditioning, making the conditions manageable.The open-air venues will not be so forgiving. Temperatures have topped 100F at six of the 16 stadiums around kick-off time during the week of the game at least once in the past 10 years. Conditions can feel even more intense at pitch level, according to Aaron Mentkowski, chief meteorologist for WKBW-TV Buffalo.