42MPG Average...

Grill block, grill block, grill block.

After that, maybe an engine block heater (LOVE mine) and it def. helps with mpg's in the winter.

And then after that, of course your obligatory recommendation to make sure your tire (or tyre for those on the site that arent 'Murican, lol) pressures are proper. 42psi in the front and 40psi in the rear is where I keep mine. You might experience a minor gain from using synthetic engine oil as well.

OH! I almost forgot.... if you set the heat temperature to it will run the ice almost all of the time. So what I do is run my engine block heater on a timer from 4am-8am. I put the heat in AUTO with A/C off (have to manually press the A/C button to turn it off) and put it on HI temp until the heat starts blowing out the vents. THEN I put the heat temp to 72F. This seems to be the cusp of which the Prius programming will not run so rich/run the ICE all of the time. When you do that, you can watch your mpg's go up. Keeping the heat on HI temp all of the time will kill your mpgs.

 

I know it's cold this time of year in Denver - lived there for 25 years before moving to the west coast, and now on the east coast. Dump the warm-up time - no more than 30-60 sec's, then drive moderately for first mile or two. If you have heated seats, keep your hvac system off during the first few minutes will speed warm-up times too. Grill block will help get the ICE up to warm temps quickly. Get your car serviced regularly and use the proper oil/fluids, check tire pressures, etc. But I do know some suggestions are hard to do when temps are below zero!

 

and make sure your 12v is upto snuff.

 

Keep in mind you are getting winter blend gasoline with a bit less energy content and I think the the rolling resistance of tires goes down with higher temperature...so you got some barriers

 

Yep - don't compare until summer, then make sure you're not fighting a headwind. Make sure your tires are at the max pressure for you - remember the rating is for a cold day at sea level for a warm day high in the mountains, then a safety factor after that... From 0 to 10,000 feet is an increase of over 40% in pressure, and from freezing to 100 deg F is another 15%. So that tire you pumped up to max on a cold day at sea level is going to be 1.6 times that pressure at halfway up Pike's Peak on a hot day. Then the safety factor.

Depends on your drive too. My '08 Prius only gets about 2 mpg better than my '04 Corolla did on the freeway. A lot more comfortable though... However, it gets like 10 mpg better in town.

 

I usually try to get through at least the first two or three traffic lights before turning on the climate control. It's easier to get away with with the car parked in an insulated garage though. Then I just use the second fan speed at around the 72-deg temp setting so that it isn't drawing too much heat off the engine. It seems to help not to use "auto" on the climate control--that causes a lot of heat and energy draw.

The higher tire pressure definitely helps the tires roll when it's cold. I use 44 psi front, 42 psi in back.

Driving in snow definitely drops the MPG a good chunk, as do the low temperatures. Thank goodness it's been warming up back into better hypermiling temps (edit--I spoke too soon!). If only we could get a break from the wind for a few days, eh?