The Caipirinha is a delicious concoction that is served by the bucketful in Brazil, but when made with quality ingredients it is a very respectable potion. The Cachaca is key to the exotic flavor, but you can do fine with white rum - then the only difference is serving it over shaved ice as in a Mint Julep.
In my humble opinion, going from a Mint Julep in June to a Caiprinha in July is a perfectly natural progression as the Earth tilts increasingly into the torrid zone.
When you order a Caipirinha, remember that the Brazilian/Portuguese "nh" sounds like an American/English "ny". The second "c" in Cachaca is pronounced like an "s".
Of course, if you mix your own then it doesn't matter how you pronounce it!