Temperature Oct 30-nov 18 in Tibet?

I have no idea which part you will visit, so here is the temperature in Lhasa for your reference: -3C ~ 14C during that period. It can be a little bit cold, so you should prepare coat and thick pants. It will be cloudy in late Oct. - mid Nov. and light snow may fall.

In Apr. it can be good timing to visit. There will be many sunny days, and rainy days may also happen. The temp may range from 4C to 22C in the whole month.