The summer months, in particular July and August, see the highest temperatures and the biggest crowds, with people attracted by the golden beaches and hours of sunshine. Rain is almost unheard of at this time and The Algarve boasts more hours of sunshine than California, while water temperatures are usually at around a perfect 21°C.
Many people choose to come to the Algarve outside of the peak times, the weather is still very pleasant and rainfall still low (there are small amounts of rain from November until March), and of course you can benefit from fewer crowds of people. Maximum temperatures throughout the year range from 15°C up into the 30s and really cold days are virtually unheard of.