At Fuelly it's possible you can find cars in northern climates and view the effect of winter on their mileage. The easy way is to look at Canadian cars, Those have little canadian car badge. It's not hard to find examples where Jan/Feb is 30% lower than Jul/Aug. It would be awesome to have a bigger pool of data. Helps to set expectations.
when i was running my gen II's about 15 miles a day, the mfd would drop from around 65 mpg at best, to 55 mpg at worst. that was using every strategy i could think of do mitigate the issue.
I may not live in the Northern extremes of the USA; however, I do live in Indiana and we do get cold winters. I purchased my new 2015 Prius C last month, and I am on Fuelly. I commute 80 miles round trip each day, so I will be able to compare my last month's average to the winter months ahead. Same username on Fuelly as on here.
It's almost more of an east-west thing. I mean, we're in the "great white north", but seriously, our west coast winter isn't that different than Oregon, let alone Washington. I mean, comparing to someone in the north central States, we're in the banana belt.
I don't think that mpg estimate on the Prius car display is that accurate. I know for a fact I was getting much better gas mileage in the summer time (probably with summer blend gas), but my MPG display doesn't show much a discrepancy. Just when I'm filling up, I notice I put way more fuel in the car than I should.....and I don't get as many miles.
Yes we get a winter blend here in CA. In summer heavy driving season, they have to use a more expensive formula that reduces emissions.
Here in Las Vegas, my C will do better in the (cooler) weather as the A/C isn't as taxed. For the month of Oct I averaged around 55MPG.
Four winters with a Prius in Iowa and on average I take a 20% hit on fuel economy between summer and winter (summer around 50+ mpg, winter around 40+ mpg). Same difference on my non-hybrid vehicles.
Here's the mileage I've gotten for each fillup, living near Washington DC. It starts in September 2014, and goes to October 2015 51.8779 51.94631 54.79042 52.73366 50.24079 50.57285 47.35103 46.78657 45.29866 46.38568 43.46834 40.02859 45.36011 46.39089 45.98467 46.1026 40.81025 39.57509 46.81859 49.05199 51.48891 53.00582 52.29531 52.69938 54.46077 50.08777 53.87205 51.05571 53.65739 51.76751 50.01238 52.92547 49.95934 52.4968 51.37663 52.90083 51.76607 54.50788 52.32216 51.83612 52.75862 As you can see, the warm weather gives me 50-54 mpg, and the cold weather gives me 40-47mpg. It's realistically more like 45-47 mpg in cold weather, and 40ish mpg in the snow/ice where I brake/accelerate more often. That's what I've found for my driving style, climate, and driving pattern (my mix of highway and local heavily favors highway, but the morning commute at 8:30am on the highway is normally around 15mph, whereas the evening commute at 7pm is around 65mph). For people with different driving styles, climates, or driving patterns, different results should be expected.
