I generally get better than 53 miles on a charge even in the cold weather. I have gotten as high as 83 miles in the summer. ---/cut/
My VOLT is a 2017 model, it was manufactured May 15th, 2016. My mileage reflects what RalphB has seen. In Summer temps, 70 deg F or better, I routinely get over 80 miles per charge (verified by the odometer miles) and now in winter, getting around 40 miles. You will see a better reading if you leave the heat off, lol, but not many of us are willing to sit in a cold car.
I realize that my numbers would be impressive if not for the fact that I am easy on the car out of habit. My 98 Eldorado had a Eco reading that gave miles remaining and Ave Mileage estimates. Driving easy would show high mileage range, driving hard would drop the mileage like a rock.
I found that driving the VOLT is much like driving the Eldorado. THE BIG DIFFERENCE is in the regen and the ability to regen and coast. I have noticed that most of the attention has been on the regen capability but when you coast, the miles are calculated vs energy used / saved. These miles will be added / removed as calculated to your range as an on going range estimate and will reflect the added / deducted electric range.
I noticed that the ODOMETER miles are always very close to the summer mile estimates and sometimes are more than the EV range miles. This is all changed when the ambient temperatures change, or WINTER temps. The Cold air temps affect the battery chemistry and when the user puts on the heat the miles range will drop by HALF (my observation).
The way you drive the car has big affect on what you will see in mileage. True, the car is engineered to give a certain amount of mileage and if we all drove the same, like robots, we'd probably get the same mileage under similar circumstances. But I feel the BIGGEST cause of lost mileage is the drivers driving habits. Everything else is pretty much the same as far as the car is concerned.
SPEAKING OF ICE.... My car, so far, has never been driven on the gas motor. My miles have been all electric by choice, but I do not do a long commute on a high way where speed limits are 70mph.
In the back of my mind, I realize that the Electric is best used in the city or on flat terrain. I have even read where it is best to use electric if you are in stop and go highway traffic as the regen will frequently be in use. Some comments had said they saw their battery show an increase in range. But for hills and highway, the ICE is most likely the best power source. Just my thoughts