We camped there in May. I do not know about winter, except to say that if the roads are wet, you probably shouldn't go in. I called the BLM Office in Monticello UT before we went in and they had current road conditions.

Winter...absolutely! Just check the weather before you go. Too windy and the sand will strip a layer of skin off you. Too wet

As everyone else has said, it is mostly about moisture and road conditions. That applies for year round. To be honest, the area only gets about 6" of rain a year so chances of it being wet are slim. If you are prepared for the temps, winter would be a great time to visit

Yeah, It’s open year round. It’s BLM, so, 14 days per spot. If it’s wet, I’d avoid it. It does dry out pretty quick,though. They do get snow. So, pick your dates well.

I have been there in the middle of Nov and again in March and April, but never in the middle of the winter. Due to the elevation I would suspect that winter camping would be a bit on the chilly side.

Yes, but you do not want to go there if it's raining, will be raining, or has just rained. While most of the main road has some gravel on it, the entire Four Corners area is "blessed" with a type of clay which, when wet, is impassable. Doesn't matter if you have four wheel drive, all wheel drive, and/or mud tires. You won't go anywhere until it dries out. You can barely walk in it. But, if it's dry (which is often in the winter), it's a great place to be!