Let me list the seasons in Copper Canyon according to MY preference:
1. Winter wins first place for me for several reasons. By winter I mean November through mid February. The lowlands are a cool temp and this is a big plus. It is a great season to go to Urique or Batopilas as well as down to El Fuerte in Sinaloa. Upper areas can be cold and even snowy but the daytimes are usually moderate. Beyond this there is usually some water left in streams so you have some good waterfall viewing at Cusarare, Temoris, and Basasiachi.
2. Late summer comes in second. I am sure this surprises some- I have even had guides tell me to avoid this season but I love it for several reasons. The rains make it fresh. The greenery is out, and there are few crowds. During this time we stay at upper elevations and it is delightful.
3. The fall- like October especially. This is the traditional “best” time and it is nice. Good weather, good views and moderate crowds.
4. Spring and Semana Santa. To me the crowds are a bit much, the Holy week celebrations lack authenticity, and it is dry
5. Late May into June. It is hot, dry and dusty.