Hi Meera!! Welcome to the Forum!
Most of the time I am helping people find ways to have their roses survive winter, so this is a nice change!
If you have already purchased your roses, than this is a mute point, but could be remembered for future purchases. Consider using the lighter-colored roses. Red, orange and lavender roses are effected by heat stress a lot more than white, light-pink and pale yellow roses.
Plant more heat-susceptible roses where they will receive some protection from the hot, afternoon sun. When doing this, remember that they still need at least 6-8 hours of direct sunlight. That sun should be "morning" or Ã¢â‚¬Å“eveningÃ¢â‚¬