A thunderstorm swept through the New York-New Jersey region on Saturday, forcing staff and volunteers at the World Cup final venue to scramble for cover as heavy rain and loud thunder rolled in. Yet the more persistent concern hanging over Sunday's Spain vs Argentina showdown has been the thick haze from Canadian wildfires that has choked the northeastern United States for days. Main Developments Air quality warnings remained in effect across a wide swath of the US east coast on Saturday, with New York City briefly recording the worst air quality of any major city in the world on Friday. The lingering smoke from wildfires sparked earlier in the week has reduced visibility and raised health concerns for players, fans, and organisers ahead of the final. FIFA confirmed it is in close contact with local authorities, continuously monitoring how both the wildfire smoke and the storms are affecting stadium conditions for the match. Spain's last training session at a nearby Melanie Lane Training Ground was suspended due to storms and lightning, in line with US storm safety protocol, according to the Spanish football federation (RFEF). Read also: 3 Demands as Thousands Rally in London for Gaza Ahead of New PM Argentina held its outdoor training session as scheduled at 1:30pm local time, with players showing no visible concerns about air quality or weather. FIFA stated that no alternative time slot would be available for Spain to complete their training. Background The Canadian wildfires that generated the smoke began earlier in the week, sending plumes southward across the border into the United States. The resulting haze has been particularly dense over the twin host states of New York and New Jersey, which are jointly hosting the World Cup final at the New York New Jersey Stadium, formerly known as MetLife Stadium. On Saturday afternoon, a thunderstorm passed directly through the stadium area, prompting state police to urge everyone in the seating bowl and on the field to take shelter. New Jersey Governor Mikie Sherrill issued warnings about potential damaging winds, tornadoes, flash flooding, and large hailstones from the storm system. Meteorologists have tied the intensity and duration of the wildfires to climate change, noting that they are burning longer and faster than historical patterns would suggest. The fires have created a thick, soupy grey sky that has persisted for days across the region. Why It Matters The World Cup final between European champions Spain and current title holders Argentina is scheduled to kick off at 3pm local time on Sunday in East Rutherford, New Jersey. With millions of spectators and a global television audience watching, any disruption to the match or health risks to players and fans would carry significant consequences for FIFA and the host nations. Air quality forecasts show improvement from unhealthy levels on Saturday to "moderate" air quality for sensitive groups by Sunday in East Rutherford. This means little to no health risk for the general public on match day, according to experts. Temperatures are predicted to reach around 27C (80F) with light breezes and low humidity at kickoff. The situation underscores how climate-related events can intersect with major international sporting events, creating logistical challenges that organisers must navigate in real time. The smoke has already disrupted preparations, with one team unable to complete its final training session outdoors. What's Next Senior meteorologist Tyler Roys of AccuWeather expects the storm front passing through the region to largely move the smoke out of the northeast before the final. Some lingering haze may remain, but the thick, eye-popping smoke that led to poor air quality is not expected across New York City or much of the northeast by game time. Chief meteorologist Jeff Berardelli of WFLA-TV echoed this forecast, stating the storm front will "sweep the atmosphere clean," leaving only a thin smoke that spectators may still smell in the air. "It won't be dangerous anymore," Berardelli said. "It's going to be dramatically better." He added, "You couldn't have asked for much better weather for the World Cup." Both experts predict the heavier smoke on Sunday will be concentrated closer to the fires, hanging over parts of the Midwest and Great Lakes region. The match itself is expected to proceed as scheduled, though lingering questions remain about how future climate events might affect large-scale sporting gatherings.