This is the very reason I always recomend my customers to wait until it actually gets hot outside, then I can properly recharge their system. Here in Las Vegas Nevada USA we will see ambient temps of up to 120*F. When its 100*F outside I can easily pump in freon till the aux fan kicks in then continue to add a little more till I see 320 over 45 @ idle. Measuring the freon exactly to the cpacity specs always seems to work the best. But sometimes adding some freon when its still not that hot outside will result in overfilling when the temps rise to 100*F. Here when it gets over 105*F I tell the customers to be happy if the system is cooling at all!
Most new cars work great but the older ones suck and sweat.....