Soccer Nova Scotia has a document outlining this topic. It can be found here. SCB would like to be a little more specific about this document so there is less confusion.
For drinks and cooling breaks:
If the humidex is between 25C and 29C, do a one (1) minute drink break each half.
If the humidex is 30C or greater - do a two (2) to three (3) minute cooling break each half.
35C or greater - SCB will normally cancel any games where it is forecasted or believes that the humidex will be 35C or greater at kick-off time. Note this could mean that a game starting at 6:30pm could be canceled but a game at 8pm isn't.
Teams with lack of substitutions - there will be times when a team or both teams playing in a game will not have any substitutes or only 1 or two substitutes. SCB would like you to err on the side of safety in these cases and allow for a drink break for the teams, even if the humidex is below 25C, or a little longer than a minute if humdex is greater than 25C. We will leave this decision up to the discretion of the referee based on the number of substitutes and what the temperature/humidex is at.
The procedure for implementing a drink or cooling break: