What direction to start out?
 

My RTW trip starts next May, somewhere around 2-5 years on the road. I am leaving from Colorado in the USA.

I would like to start with Central America and South America, but I was wondering how much trouble I will run into traveling through Mexico in the heat of summer (June) and South America while it is still winter down there?

Would it be better to head north to Alaska for the summer and wait until September to reach Mexico then arrive in SA for their spring/summer?

I have considered starting with Russia/Mongolia, but something keeps nagging at me that it would be a bad place to start out....not certain why.

Comments? Suggestions?

I believe that hitting Mexico lat Sept. early Oct is supposed to be the best time. Avoid the rain...

Depending on how fast you want to go, you could follow the dry season all the way south.