Although the Algarve is not in the Mediterranean (it has an Atlantic coastline) the climate is warm and conducive to eating out, water sports and other activities requiring generally sunny or even hot weather.
Like almost anywhere in the world the weather varies from year to year however, in general, the climate is not very dramatic except for the occasional thunderstorm. Normal weather, in terms of hours of sun, and the amount of rain are shown in the charts below.
Given that the climate is generally hot, until recently (1996) there has not been any shortage of fresh water. This is because in most years there is normally sufficient rain in the Autumn (Fall) and Winter seasons to top up the reservoirs. As far as the tourist is concerned, there is no water shortage despite the lack of rain in both Portugal and Spain in the past few years (1996). When it does rain it is often in the form of the odd wet day or heavy thunderstorm, so although a month may appear to be relatively wet, most of this may come in the form of one or two thunderstorms or very heavy showers.
As for temperature, it only takes a wind from the south for the temperature to rise well above average winter levels as experienced in late 1998 and early 1999 (21C - 70F). NOTE:- Maximum temperatures are several degrees higher than those shown in the chart below.
As a large number of tourists stay close to, or visit the beaches every day, many are caught out and badly sunburned as the sea breezes can reduce the apparent temperature considerably. It is advisable to take care when in the sun, both on the beach and around the pools.
In recent years (early '90s) the Algarve has experienced some exceptional rainfall in the middle to late Autumn (Fall). These anomalies are, of course, not shown in the weather information provided by tour operators. In 1989 very heavy rain washed away the ancient bridge at Tavira (near Faro). This has now been rebuilt
As mentioned above, the Algarve is not in the Mediterranean but has a coastline bounded by the Atlantic. This means that the sea is not as warm as places in the Mediterranean. As shown in the chart above, the sea temperature is quite acceptable in the summer months however the temperature gets cooler the further west you go. The big advantage in having an Atlantic coastline is the lack of pollution. A large number of beaches have been awarded the EC 'Blue Flag' for water quality. This also means that the fish and shellfish are of a very high quality with a low risk of contracting food poisoning. Do try eating the fish!. Scuba divers should be aware that there can be a substantial temperature difference as they descend. It is quite common for cold Atlantic water to underlie the warmer Mediterranean surface layer. This cold water can have much reduced visibility due to plankton (3 to 4 metres).
Every Summer the Algarve is invaded by the smell of coconut oil and other lotions as people roast around the pools and on the beaches.
More seriously, the need to protect against excessive ultra-violet radiation has reached the attention of the public these days. For those who wish to gloat, it is still possible to see fluorescent pink bodies groaning both in the bars and around the pools.
The sun in the Algarve is hot, and will burn you quickly so be warned! This is true for most of the year!
As the Aussi's say - "Slip, Slap, Slop" or in English