2025 gas mileage drop in winter?

I bought my 2025 in June and after it was broken in I was getting about 48mpg. I recently passed 10k miles and it seems like once the weather cooled off my gas mileage has dropped quite a bit. I'm now getting about 43 mpg. I know it's not huge but it has been the difference between being able to drive to and from work all 4 days that I work (1 hour each way) to needing to get gas in the 3rd day. I had a good routine of filling up every Monday morning and not needing gas the rest of the week which was nice, but now it's about the same as my previous car that was a non hybrid civic. I wonder if the heater burns more gas or if the winter gas mix just gets worse mileage?