Cold has never really bothered me to be honest - it's just the water! I hate the squelch and having to dry shoes out, it just seems to take forever!
My wet kit currently consists of GripGrab Hammerhead overshoes with Endura Stealth light tights (over the top of the overshoes) and SKS longboard mudguards - and yet I'm still getting wet feet within a 40 minute commute with heavy rain
Maybe the tights aren't doing their job well enough and letting water down the top of the overshoes.
I know I have an issue with water hitting the front upper mudguard stay causing water to drip directly onto my shins and feet. Have tried taping the inside of the guard to stop this, but with little benefit. I know I could move the stay bracket to the outside or go with thiner tyres, but I'd rather not.
Might buy a velomobile.