'Breakers' - are tripped because they are exceeding their amp limits.

The 'hotter' it gets outside - the 'harder' your AC has to work - and under normal circumstances this is not a problem - but when you have a fan motor or a compressor that is starting to 'break-down' (electrically) - often the AC's amp draw will exceed the limits of the breaker - thus 'tripping' the breaker.

I would suspect either the fan motor or the compressor is causing your breaker problem.

Eventually - the component (either the fan mtr or compressor) that is 'going bad' will go out completely and your breaker will 'trip' and not stay on when you try to reset it.

At this point you will need a Service Tech to determine which one is bad.

There is a possibility that your condenser coil (the one that blows hot air) is 'dirty' which will also cause a problem similar to the one you have - but it is less likely.

Also - if you've had the AC 're-charged' lately - it's possible you are in a 'over-charged' condition - but again, this is not very likely.

hope this helps.