AC tyres are brand new each session, but took about two laps to wear off the release compound and or stickers. Now only takes about half a lap.
Temperature range is now 45o to 70o. And being cold has less effect on grip. Cold days will still not generate enough heat but anything above 26o ambient should be fine.
Tyre warmers could be used on the server as they are only set for 38o, think of them as being laid out in the sun.