Outdoor cameras that work well with the cold weather that we get in Minnesota and Wisconsin can be a tricky thing!
I have used box cameras with heated environmental enclosures many times and they general work fine in any temperature. A negative is that they usually are big and clunky looking, which is fine for industrial and commercial applications but doesn't look really great in residential or fancy commercial settings. One thing that I have seen over the years is that many installers don't run a separate power source for the heater and just use the same power source as the camera. CCTV power supplies are separated into channels so that each camera has a separate fuse. An 8 channel, 8 amp power supply would have 8 fuses of 1 amp each so that if one camera had a problem it would blow one fuse. I feel that it is better to run the heater on it's own channel because often the required current for the camera plus the required current for the heater is at or near the fuse rating, which can cause problems down the line. So if I was installing 4 outdoor cameras with heated enclosures on a job I would put in an 8 channel power supply. I am sure some will disagree but it works for me.
I have used some other cameras for cold weather use. Bosch has an extreme series (Used to be Extreme CCTV until Bosch bought them) and I have used the WZ16. It is a bullet camera with IR and is rated to -20. It is a good camera and has held up well. My favorite cameras are made by Digital Watchdog. They have a series of dome and bullet cameras in their Starlight series that are excellent. They all have some of the best low light capabilities I have seen, are very rugged and have great optics. The DWC-V3363DH is a dome with built in heater that is rated to -40 and they have a couple bullets that are rated to -10. The Digital Watchdog Starlight series has several models to fit just about any indoor or outdoor situation and I use them a lot on installs. Of course, the downside of these cameras is that they can be a bit pricey!
On the other hand, I have used 8 IC Realtime EL-1000 cameras that are only rated down to 14 degrees on a job and they have gone through 2 winters now and even when it got to -20 to -28 they never failed! They are outdoor rated but do not have a heater but yet still seem to be able to handle the cold, so go figure!