This weekend the annual Formula 1 British Grand Prix will be held at Silverstone on the Bucks/Northants border and as with all motor racing events, the weather can play a massive role.
The most obvious weather element that determines race tactics is rain.
Not only does spray reduce driver visibility, but a wet race means less friction between tyres and track, increasing slipperiness and so making it harder to keep the car on the circuit.
As a result, different tyres are available for wet weather, with both ‘intermediate’ and ‘wet’ options, in addition to the normal dry weather ones. The crucial decision is which of these to use.
A ‘wet’ tyre used with only light rain and a virtually dry track can result in these higher grip tyres overheating, whilst lap times are increased. However, if ‘normal’ or ‘intermediate’ tyres are used in properly wet conditions, skidding and spinning off the track becomes more likely.
An added complication arises when part of the circuit remains dry and another wet - often the way during scattered showers.
Meteorologists study the latest radar during the race, so that quick decisions can be made as to whether a tyre change is required. Lap times and overall car performance are highly sensitive to engine, tyre and brake temperatures, and both the ambient and road surface temperatures will influence these greatly.
Hence accurate temperature forecasts are vital.
In summer, road temperatures may be 20C higher than the air temperature during the early afternoon on a sunny day, whilst if wet, this difference could be only 2C.
Humidity also plays an important role, both in terms of the behaviour of the cars and the well-being of the drivers. High humidity means evaporative cooling becomes less efficient, making it particularly uncomfortable and potentially dangerous for the drivers.
As for the forecast for Aylesbury Vale, the rest of the week will be very warm with plenty of sunshine. Turning unsettled at the weekend though, with brisk winds and the threat of rain for Saturday qualifying at Silverstone.
Cool with the chance of a shower or two for the race itself on Sunday, so those wet tyres may well be needed.