The vehicle was advertised as getting 40mpg city and 34mpg highway. We purchased the vehicle in August and were very happy with the gas mileage during the summer and most of fall as it was usually 38mpg or better city or highway. When the weather got cold though, the gas mileage dropped significantly and was generally below 30mpg. Took a while to figure out why but it turns out the vehicle basically runs the engine as a generator to run a space heater to heat the cabin when its cold and you have the heat on because it can't rely on the heat from the engine alone. This is because its a hybrid and the gas engine is not always running.

We have not been able to come up with a good solution to this point other than trying to minimize the amount of time the heat is on... but in the winter here in Maine you basically need it on all the time on low at least to keep the windshield from fogging up and to keep the cabin at a reasonable temperature. Not sure what other auto makers do but our friends with the Rav4 hybrid have not experienced this issue.