Winterize? What's that? Two seasons where I live--Summer, and February. We can and do run the boat year-round.
The first time Marie and I went to the area of the photography was late Fall 2002. We stayed overnight in Needles, and a storm had come through overnight. The area had not yet been labeled as "Mojave National Preserve", but the hand-over from BLM to USPS was under way per the 1994 Desert Protection Act.
Once we climbed up westbound on I-40 atop the plateau west of the Colorado River, there was snow on the ground. It has rained pretty steadily in Needles, and at Goffs there was about 3" of snow on the ground. In 2002, a lot of the town was still standing--most of it is gone now. The storm had blown out, and as is common in the desert at such times the temps dropped markedly. We were in the area close to the photos that day--about 25 road-miles from Goffs (northwest as the crow flies)--and the snow depth was about 6". It was cold for mid-November in California, about 20* at 1 P.M. It can and does snow in the high desert--and can get bitterly cold (for California) on occasion. Winter of 2013/2014 was one such time--I drove from Ridgecrest to Las Vegas to attend the SHOT Show that year, and the temp gauge on my truck showed 1* above zero at the summit of Mountain Pass, a few miles west of the NV state line along I-15. Nothing in most of California is built for temps much below 20*, and plumbers made bank that year and in 2007.
So, real winter CAN occur here--but it's infrequent.