Gas mileage going down

I have a Niro and my fuel mileage drops in the winter. The battery is not as efficient in colder climates.

Don't top off as all you are doing is wasting gas. Keep doing it an you will end up with expensive EVAP system repairs.

Lower battery performance in cold weather will probably reduce fuel economy in a hybrid.

I also have a 2019 Kia Niro and driving around town conservatively, I am getting only 25 mpg on average. I just bought the car a week ago and wouldn't have bought it unless it got the mileage that Edmund's claimed (51 city/46 highway). I can eke out 51 mpg if I roll through stop signs and hit green lights. So far, I am disappointed with this car.

I live in Quebec Canada. I have been driving for 597 months or more than 48 years. Here in Sub temperate geographical climate that often drops below freezing temperatures,, it is quite normal to get as much as 30% less fuel economy in winter compare to summer. The laws of physics dictate that liquid and gazes behave differently in cold compare to warn or temperate weather. Since it is gazoline vapors that burn in internal combustion engines ignited by a spark generated from the battery; in cold weather gazoline vaporizes less therefore more gazoline is required to power the engine. Also freezing temperature reduce the amount of conductivity of batteries because the liquid and the plate materials are cold.

I had a 2018 Kia Niro (non plug in) and I consistently got over 50 MPG winter or Summer. Most often in town I got 52-56 MPG. Sometimes as cold as -10 degrees. MPG on the highway dropped to around 40. I traded my 2018 in on a 2019, same exact model, and I can’t seem to get over 35 MPG. I took it to the dealer and they basically blew me off saying there is nothing they can do. Only thing I have noticed is that my 2018 would charge the battery to 90 percent or close to it. I would then run a lot more electric and not burn fuel. The 2019 only charges to around 60 percent. Dealer told me that was normal but I’m not buying it.

2019 as new never got more than 26 mpg. In may after not driving much in pandemic, battery went dead. Restarted car using hybrid battery boost as per instructions. Some settings were reset. Car now gets 50 mpg. Why?

It has been 2 mo since reset. Still have not refueled so can't verify mpg. After reset, readout started at 38 mpg. Has gradually increased to 50 mpg. Why would it have only been 26 mpg since off show room floor? That was same as refuel calced mpg