I live in upstate NY and our average winter temperature has been 17F for most of the winter. I got my Prius in December and average mileage was about 37 mpg. Now our temperatures are averaging about 40F and my average mileage has jumped to 49 mpg. I have tried all of the techniques you described like the feathering and they worked well, but when it is very cold the ICE runs more often to keep the battery charged. I am looking forward to the warm season to see how much more my mileage improves.


Treehugger