We visited the Grand Canyon one year in early-mid March. It was not our intention to go to the canyon, but when we pulled into Flagstaff early in the morning, we were behind a snow plow, 4-6 inches of snow had fallen overnight. Our plan was to head to Phoenix, but I told the DW we had never seen the canyon in snow. Had been there several tines, but always in summer.
We decided to head on up route 380 (I think) out of Flagstaff to the canyon. The road had been plowed, but it began snowing again. Driving the rig in my sig, we only had one bad area on the route, which was a section not protected by trees. The wind was blowing hard and the snow almost became a white-out. But we continued on, SLOWLY, for about 1/2 mile till we got back in the forested area. When we got to the canyon, we were rewarded with sunshine and some beautiful views of the canyon in snow! We toured the southern rim till it started to snow again and then headed back to Flagstaff, again having wind driven snow in the open section.
Being from PA, I am experienced driving in snow. If, perchance you run into snow, just go EASY on the gas and brake pedals.