I am fairly certain you can make fairly easily then as it will be spring, so even if they have some storms, the road should be melting clear fairly quickly. OTH, your riding in the mountains would be could be fairly limited due to excess snow. I don't know if I'd want to bike all of Patagonia and be forced to stay out on the Pompas for all the ride. W/O time spent in the mountains, I think it'd be more of an "I did it" sort of trip as opposed to an amazing tour of some of the world's best scenery.

Perhaps, check on Lonely Planet thorntree to see how fast the snow melts from the roads/mountains of Torres del Paine, El Chalten, the Caraterra Austral and the Lakes District.

Maybe you could shoot down the coast road to Ushuai and head Ruta Cuarenta, side trips to the mountains and the Caraterra Austral on the way back.

just did it in october
 

apart from caught in one blizzard the weather was great ,yeah your right about that wind ,hard work on the gravel roads ,,keeps wanting to take out your front end ,but wow how good is it down there
dave

Good job Dave!!!

Riding into and out of Ushuaia was one of the highlights of my ride. Looking back on it almost two years later, the Tierra del Fuego part is a magic dream. Sitting comfortably in my dining room looking at the start of a Wisconsin winter, and my motorcycle parked under a cover, I'm... I can't believe I did it- rode through the snow over the mountains to Ushuaia, then back over the ripio in the mud with the wind making it impossible to see.

I must have been insane.

You are my kind of crazy!