If you know the feeling of beeing thirsty during exercising in a hot environment, creeping for this cold, chilling refreshment during your workout, this "tutorial" is for you. It's actually so simple it's more a hack than a tutorial.
To keep your drinking water cold and cool in a hot climate, just take some socks, make them wet und put your bottles in them.
The evaporation to dry the socks will need energy which will keep your refreshment cold. I used this while cycling in south of spain at temperaturs of 35°C and it helped to keep things on a chilly temperatur for hours.Works especiialy well when there is wind. I think some drivers do the same by hanging their bottles out of their cars.