Weather update
Overnight, the area of high pressure that brought fine weather today will be pushed aside by an advancing low pressure system, bringing rain to all parts of Quebec on Saturday - and could have a big say in determining the grid for Sunday's race.
Tomorrow will start mainly cloudy as the beginnings of the system moves in, but there may be one or two brief sunny spells in the morning. Final practice will remain dry, but it will turn overcast towards the start of qualifying. Light showers may hit during the session itself - particularly towards the end of Q2 and into the final ten-minute segment. If there are any red flag periods, then clearly the rain risk becomes greater as the session window extends.
The showers will merge into prolonged and much heavier rainfall later in the afternoon, through the evening and overnight into Sunday, leaving the potential for scattered showers during the grand prix.
Temperatures will be down a degree or two on today's high, with a maximum of 21 Celsius in the air, but track temperature will obviously suffer greatly, peaking at around 25 degrees. This largely depends on precisely when the rain reaches the circuit.