Only got my Clarity in late Feb so I only have experience at temps in the low to mid 30s F. I didn’t have my Level 2 EVSE for the first month so I couldn’t precondition and car was outside.
When I was first driving the car, I wanted to see what the best EV range was, so I didn’t want to run the heater (cheated briefly once or twice). Never ran the rear defroster. Keeping on my coat and gloves, the seat heater alone was enough to get by for me, but if my wife had been onboard, the heater would have definitely been on. I was able to get low 50s EV range but temps were always higher later in the day.
This winter I have Level 2 in an unheated garage and plan to precondtion and use seat heating only after start up which should give me comfort and range. Time will tell when we hit 20F (only have a few days below that).
The only concern is that being retired, I don’t have a set time to be able to use pre-conditioning on a schedule. I’ll have to remember to use the fob before I get into the shower. It will probably take a few cold cars to train me to remember it!
To be honest, I’ll add the preconditioning kW into the charging kW when figuring cost per mile and MPGe. It will be interesting to see how much of an effect that will have.