The busy-ness numbers on this page are not an impression. They come from the national count of overnight stays in Algarve tourist accommodation, averaged over the last three complete years and scaled so that August, the peak, is 100.
On that scale August is 100 and July 89. Then September 75, June 72, October 65 and May 63. That ordering is the useful part: September is often described as the calm alternative to summer, but it runs a little busier than June, and it is May and October that are genuinely the quiet end of the warm season. January, at 17, is the quietest month of all, and almost nothing sails.
Two things this count is not. It counts people sleeping in paid accommodation across the whole Algarve, so it misses day trippers and everyone staying with family, and it says nothing about how many boats are at the cave on your morning. It is a measure of pressure on the region, and it is the best measure that exists.
What a rainfall figure means here. The millimetre figures are a total depth for the whole month in an average year. They are not a daily rate, and they say nothing about how many days were wet, which is why the rain-day count sits beside them. A month with one storm and a month of drizzle can total the same. The practical version for Benagil: from June to August rain is close to irrelevant, at 5.1 mm, 0.9 mm and 3.0 mm, while December takes 90 mm. And rain is not what stops a trip anyway. Swell is.
What a sea temperature means here. The sea figures are an average for the month from satellite measurements of open water a few kilometres offshore, not a thermometer in the cove. Water over sand inshore usually runs a little warmer in summer, and Algarve upwelling can pull the coastal temperature down by several degrees for days at a time. Treat 20.8 in September as the shape of the year, not as a promise about your swim stop.
