General advice, landing and taxi in, typically achieves 450-550C. Brake fans running on chocks after shutdown and before engine start must be for a minimum of 15 minutes. Typically, if you start up and taxi after a minimum of 20 minutes and can start the takeoff with brake temps at a maximum of 200C, all OK.
There are tables within the aircraft manuals for calculating the required cooling period if brake fans or BTI are unserviceable. In service, on a hot day with a 30 to 40 minutes turnaround after a max weight landing on a 6,000’ runway, the brakes would be usually be found cool enough to start up and taxi out.