I found Jawbone Canyon is great at Christmas. I could not imagine being there in the summer! It never snowed on me at Christmas, but I have heard of it snowing on my friends at Christmas and Thanksgiving. March was getting to warm for my liking. It can be really dusty and dry in the summer, much nicer after a couple of rains settles down the dust in the fall.
I would much rather be at a higher altitude such as Frasier Peak or the off road area near Gorman. There are trails connecting Frasier Peak antenna's with the off road area in the valley below. Lots of great views from the mountain top.
I would recommend that you check out Gorman on Google maps, and have it as a back up plan in case Jawbone is not to comfortable. . They are not that far apart if you take 14 south to 138, then west to Gorman. Or look for a riding area near Lake Isabella. It is a higher altitude, and thus cooler.
Good luck!
Fred.