How will the weather affect the opening games of the World Cup?

Storms causing delays to some of the warm-up matches this week have already shown how extreme weather will affect this World Cup.

And with more storms forecast, some of the opening games are likely to be affected with the biggest risk to play coming by Monday.

Scotland start their campaign in a pleasantly warm and dry Boston on Saturday night (Sunday morning UK time).

Then for England, the Texas heat may be uncomfortable for fans leading up to their first match against Croatia in Dallas on Wednesday.

For Thursday's opening match in Mexico City, it is likely it will be the altitude not the weather that players and fans will notice.

The World Cup officially kicks off on Thursday afternoon (20:00 BST) in Mexico City.

South Africa will be taking on one of the hosts Mexico.

While the weather forecast shows showers, these shouldn't be particularly heavy. Temperatures will be around average of 23C (73F).

Mexico City is however the highest World Cup host city, at around 2,200 metres above sea level.

At this altitude the air is thinner and means that there is around 25% less effective oxygen per breath and therefore will have an impact on the players.

Thinner air also means that the football will travel faster and further, have less curve and behave more unpredictably.

On Monday, Saudi Arabia take on Uruguay at 18:00 ET in Miami where the temperature will be around 30C (86F). With high humidity forecast, it will feel more like 40C (104F).

According to the heat index used by Fifa and other sporting organisations to measure how temperature affects the health and body of a person - called the Wet Bulb Global Temperature (WBGT) - a value of above 28C (82F) is widely considered the threshold at which heat stress becomes a significant concern for elite athletes.

On Monday, the WBGT is forecast to be around 30C in Miami. This represents a high-risk or extreme environment at a level that Fifpro considers to be unsafe for play.

Storms are also in the forecast. If they were to develop within eight miles of the stadium, the match would need to be suspended for at least 30 minutes.

This allows players, officials and fans to seek shelter and stay safe from threat of being struck by lightning.

Play can resume 30 minutes after the last lightning strike in the area.

Texas is one of the hottest states in the US and England fans waiting for their team's first match to begin will be experiencing typical hot weather on Wednesday afternoon.

Temperatures into the low thirties are expected and while it should be dry and sunny, there is a chance cloud cover could increase with a few showers.

While no thunderstorms are currently forecast, the cloud cover and increased atmospheric moisture will raise the humidity.

The 'feels like' temperature is therefore expected to approach 40C.

However, the Dallas stadium is one of the World Cup stadiums with a retractable roof and air-conditioning.

This will make it much more comfortable - and safer - for players and fans when inside the stadium during the game.

Scotland's first game is against Haiti, taking place in Boston on Saturday evening local time - 02:00 BST on Sunday.

While it will feel pretty warm with a temperature of around 25C (77F), this is typical for the time of year, and similar to a warm summer day in the UK.

To see the latest weather for these and all other World Cup locations, check the searchable forecast here or use the BBC Weather app.