All NASCAR’s tracks have special vehicles and personal who vacuum heat and blow the track surface, doing as much as possible to dry the track and make it race able again. Only consistent rains will cancel or postpone a race. Sunday's event on July 18th 2021 was a great example of NASCAR working hard to bring the track back to raceable after a shower.
The decision is made in consultation with NBC & NASCAR and will be announced through PA at track, TV and notification to the teams
After everybody gets there buys food, drops some cash, then they'll call it
It will most likely be a last minute decision made by nascar officials.
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