What are the heat rules at Wimbledon?

For a second year in a row, Wimbledon is set to experience extreme temperatures north of 30C.

Last year’s tournament experienced temperatures exceeding 30C, and a similar situation is expected throughout the second week of this year’s competition.

To help keep players safe, Wimbledon has a heat rule for all singles matches when deemed necessary.

Wimbledon uses the Wet Bulb Globe Temperature (WBGT) scale to determine whether the heat rule should be enforced.

The WBGT’s heat index is a measure which pulls together air temperature, humidity and surface temperature and is measured by a heat stress monitor.

If the WBGT is at 30.1C or higher, players will be permitted 10-minute breaks during a match.

For those played under roofs, the heat rule is not utilised.

How does the heat rule work?

The heat rule applies to all matches in singles competitions, even if they have already started when the WBGT surpasses 30.1C. Only one player needs to request the permitted 10-minute break for it to be enforced.

For best-of-five-set matches – in the men’s singles – the 10-minute break will be taken at the end of the third set. In best-of-three-set matches, this is taken at the end of the second set.

During breaks, players are allowed to leave the court but are not permitted to receive coaching or medical treatment.

WBGT readings at Wimbledon are measured 30 minutes prior to the start of play, at 14:00 BST and at 17:00 BST.

Where a match is carried over to the following day with the heat rule in place, it will not apply to a best-of-three-set match that has completed one set. It will also not be applied to any best-of-five-set matches that have completed two sets.

Should there be a match in progress during which the heat rule is lifted, it will remain in place until completion of that match.

What about air conditioning?

Both of the show courts with retractable roofs, Centre Court and No. 1 Court, have the option of air conditioning which can bring the temperature down to 25C.

The systems kick in once the roofs have been fully closed and are carefully designed to minimise noise levels for broadcast reasons, preventing players from being distracted, and for local council regulations, as Wimbledon is located in a residential area.

The technology has been designed to reduce humidity to a level that ensures no condensation can gather on the playing surface or the roof structure.

It has also been made to ensure the change in the air movement does not interfere with the movement of the match ball.

This article is the latest from BBC Sport’s Ask Me Anything team.

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