I think its easier to ride in extreme cold than heat, as you can layer up or down to control your temp. In the heat you just suffer.
For me, the keys to riding in the cold are Merino wool socks and shoe covers (I use the ones just cover the front of the shoe), full fingered insulated gloves, and a head cover that comes down over my ears (I get middle ear pain otherwise). I have a very light weight outer jacket with a zipper. I'll start the ride with it fully zippered, then gradually open it as I heat up. Works great. If it gets too warm I take it off and roll it up and put it in my jersey pocket. It says it's made by Cannondale...it's probably 15 years old and I doubt Cannondale actually made it. Any light weight, full-zippered cover would do I imagine.