Travelling in Kunming between Late July - Early Aug .. wonder if it would be a good time (terms of weather / temperature) to make a trip then.

Except the rainy days, it will be a good time to travel there. The temperature will range from 17C to 26C, very pleasant and comfortable. The scenery then will be very attractive. However, shower or thunderstorm may happen during those days. Therefore, just take along umbrella or rainy gear.