Temperature-wise, that does not seem to be a problem as my summer temperatures are higher than yours and I grow them here. You will need to find a location where they can get shade in the afternoon, especially during the summer months. And you will need to find well draining, acidic, moist soil. Clay soil, for example, makes it difficult for the roots to spread and grow. If one has clay soil, you can grow them in raised beds or in pots/containers. They like evenly moist soil,with lots of acidic mulch; no periods of wet and dry soil so make sure they receive enough moisture during the sometimes drier months of Nov thru March. The American Rhododendron Society has a chapter north of you, in Sikkim.

luis_pr thanks for the help. do the plants grow during summer or remain dormant?what mix should I use for containers?what to feed them?

During the worst of the summer months, the plants (mostly Encore's & a few Kurumes) skip blooming until the worst of the high temperatures is over. I have not paid attention to see if they still show growth going on; I can speculate that they may just be semi-dormant. Roses also take a break and produce smaller blooms or no blooms.

I feed them Hollytone in Spring and let them feed off the decomposing mulch the rest of the year. Because my soil is alkaline, I amend it in Spring with garden Sulphur.

Check what acidic potting soils are available locally. Or make a mix (there are probably 400 gadzillions recommended ways). Here is a simple one: one half small/medium pine bark mulch and one half peat-based potting mix. Make sure the pot has several holes for water drainage. I add some rocks at the bottom and some people add some wire to prevent critters from burrowing into the pot from below. Pots made of cement may be alkaline so I choose pots of other materials.

thanks for your valuable guidance.