Not getting the magical mileage that is advertised for this car.

[Codylehr23]

So I bought this car a month or so ago. A 2015 with 67000 miles. My way to work is 9 MI 6 of witches highway. And my MPG has been all over the place. My lowest has been 31, and my highest average has been 38. Total of an averaging 34 or 35. it seems that the smallest changes in wind affect mileage and cold weather affect mileage also. These are not computer estimates these are top off at the pump calculations.

I did install roof racks but I might take them off to see if it helps a bit. I don't think it would affect it this much.

I'm disappointed. Today I went to pick up my daughter and the route there is 50 miles an hour almost no stops for 10 MI. And my computer averaged it out to 40 miles per gallon. Which is great, but considering it's 50 miles an hour I should be getting more than 40 MPG which is what stated for highway mileage from the EPA.

I guess I should state that I live in a part of Washington state that doesn't have a ton of flat area and there's usually a little bit of wind sometimes a lot of wind. (Oh my God this car has terrible noise with side winds.)

I feel like a Toyota Corolla could have gotten better mileage than this with the 4-cylinder. honestly I wouldn't have bought this car if it wasn't for the advertised amazing mileage. If it wasn't for a mileage nobody would buy this car lol.

Where do I need to start to figure out what's going on here? Thank you