Apis strain yemenitica which is available in Saudi Arabia and Yemen can tolerate high temperature and also efficient in summer months. May try that strain if possible
Above 50 degree Celsius might be too high for any honey bee strain to regulate their activities in summer. But I agree with Munir Ahmad that yementica is more tolerant to high temperature and better for summer months.
Yemeni honey bees have a good ability to survive under high temperature conditions but not up to 50C. The survival ability of honey bees can be enhance by providing the bees with good water resources, protect the bees from direct sunlight, house the bees in a suitable beehive type with good ventilation, and provide the bees with suitable amount of food. Also, you should take care about relative humidity, bees can survive better under conditions of high temperature and high relative humidity (about 65% or more) than conditions of high temperature and low relative humidity (65% or more).