PI tights have three distinct levels:
Thermal - Really cover the same level as leg warmers for me, ~50 in rain, ~42 in the dry
Thermal Barrier: good in rain down to ~42, in the dry maybe ~35
AmFIB: Good in rain down to snowing. Don't know in the dry as I don't ride on ice.

Get the Barriers w/o pad. Wear summer shorts under. More useful in Oregon. I wear my Barriers 10 times for every time I wear my Thermals w/pad.