Maybe, maybe not. Whether or not you can heat the plumbing well enough depends on where the plumbing is located, how well that space is insulated and heated, and how cold it gets.
Some RVs are better designed for use in cold weather than others. I'm comfortable with mine getting into the twenties for a few hours if it will be going back up above freezing for 18-20 hours a day. Much colder, or that cold much longer, I'll be winterizing. I know other RVs that can handle subzero temperatures for months at a time, with the heat running.
Experience with your RV will show you where it is on the cold weather performance scale.
Average temperatures are just that. I live in a place where the average low temperature for February is 24 F. Some winters it has not dropped below 30 on some nights, but has also been a low of -20F with temperatures not rising above zero for more than a week. Record low for Feb something like -40 F, record high for the month over 60 F. That's all going into that 24 F average. The mountains, high desert, Great Plains are very different from coastal areas, average temperatures fit into the.middle of very large excursions from that number. Grand Canyon can get well below zero in February.
Tom Test
Itasca Spirit 29B