If you can, try more like 5min. Does your bike have an engine temp indicator? You want it to read 150 or so before you get into it.
If you cant wait that long, dont get on the gas untill it has a chance to warm up.
This is not so much for safety's sake (also carbed engines sometimes act wierd when cold) but more of a longevity issue.
My first bike was carbed, and it had a bizzare quirk when cold. If you were to get on the gas the bike would stumble for half a second doing nothing, then come back with the most powerfull kick that engine could muster, In fact that was the situation when the engine would produce the most power power.
This was nothing but curious, untill winter rolled around and I went to leave turned in the parking lot, and open the gas to strieghten up.
Sliding a rear tire on icy ground is very scary when you've been riding for maybe 2 months.