Temperature effect on milages makes no sense
The setup: 2006 HCH-II, ~50,000 km on it (35,000 miles), perfect service, winter tires. I drive 65km to work (50 miles), 40-45 of them hiway.
Monday morning, sunny and warm, around 3 degrees (38 f). Drive to work and easily get ~5.2 l/100km (45 mpg). Storm comes in during the day, temperature falls to 3 below (28f). On the drive home I get 6.1 l/100km (39 mpg).
So a change of about 6 degrees Celsius results in a 20% drop in fuel economy? Why? The car is fully warmed up 5 minutes into the 50 minute drive. What's going on?
This is fairly consistent
This is fairly consistent with Hybrids, A couple of things com to play the temperature drop makes smaller Oxygen molecules therefore you have more to mix to get a good burn, I know it sounds goofy but the larger warm air Molecules don't mean more to attach to the Oxygen. Then there is the need to run it a little harder to get it to running temperature, I have found that 65-75F I get the best mileage. And yes we can be smug about it too hey we are still getting 40+ MPG most of the year. I do agree about ther humodity to some extent, there was a device called a water injector that when injected into the air stream of the inlet it cooled the combustion chamber allowing a better burn.