A dangerous heatwave is set to intensify across much of the central and eastern United States and Canada this week, raising serious questions about player safety at several FIFA World Cup 2026 last-32 fixtures.

According to the National Weather Service (NWS), temperatures are expected to exceed 32C (90F) across wide areas, but the combination of extreme heat and high humidity will push the "feels like" temperature to as high as 46C (115F) in parts of the southern Plains, the mid-Mississippi valley, and sections of the Mid-Atlantic.

Fifpro safety thresholds under pressure

The relevant measure for player welfare is the Wet Bulb Global Temperature index, which accounts for both heat and humidity. Global players' union Fifpro uses this index to determine when conditions become too dangerous for professional footballers to compete.

Several matches this week may approach or reach that threshold — particularly fixtures in Miami and Kansas City on Friday 2 July, where the feels-like temperature could climb to 40C (104F). Both Argentina v Cape Verde and Colombia v Ghana could be played in especially punishing conditions.

Match-by-match heat outlook

The most intense heat will be concentrated in Texas, where fans travelling to air-conditioned stadiums in Houston and Arlington will bear the brunt outside. In Houston, the feels-like temperature for Brazil v Japan on Monday is forecast at around 44C (111F), while Dallas faces conditions of up to 41C (106F) on Tuesday.

England v DR Congo on Wednesday in Atlanta will also see hot and humid weather outside the stadium, though the venue itself is air-conditioned. A small risk of thunderstorms exists for that fixture, with a higher chance of storms later in the afternoon after the match.

Other matches expected to face elevated heat include:

Tuesday 1 July — France v Sweden, New Jersey: 30C (86F).

Thursday 1 July — Portugal v Croatia, Toronto: 31C (88F).

Friday 2 July — Argentina v Cape Verde, Miami: 31C (88F), feels like 40C (104F).

Friday 2 July — Colombia v Ghana, Kansas City: 32C (90F), feels like 40C (104F).

Thunderstorms could also disrupt play

The combination of heat and humidity is also expected to generate thunderstorm activity later in the week. Under tournament rules, a match can be suspended if a thunderstorm is detected within an eight-mile radius of the stadium.

The Argentina v Cape Verde game in Miami on Friday carries a high chance of a thunderstorm, which could force a suspension. Atlanta's England v DR Congo fixture faces a smaller but real risk.

Heat peaks at the weekend

Conditions are forecast to deteriorate further by the weekend, when the last-16 round gets underway. Philadelphia and New Jersey are expected to see temperatures well above normal, soaring into the high 30s Celsius — with feels-like readings exceeding 40C (104F).

Eastern Canada will not escape either. Ontario and Quebec are forecast to see temperatures up to 10C (18F) above average, with overnight lows potentially staying above 20C (70F) — a threshold meteorologists classify as a tropical night.