It isn't so much the outside air temperature, but its the tire temp. You can have a 70 degree day outside and lose it before you warmed up your tires. Also, riding when its 30 degrees, properly warming your tires before tipping it into a turn, you'll be fine. Drop a couple PSI and they'll heat faster.
Someone here made a GREAT post about how to properly warm up tires, and it isn't the side to side weave a lot of us do. There is no such thing as scrubbing in tires for the modern tire. Its getting them through there first few heat cycles that gets you the grip.
You'll see indy cars swerving side to side at the beginning of the race because that's the only way they can get enough flex out of the sidewalls of the tires to get them to heat quickly.
A bike should not be piloted in the same matter, rather quick acceleration and deceleration will put a great load on the tire as it flexes and will produce the desired result of "scrubbing in" a new or cold tire.
