Due to its protected geography, the local area has a micro-climate that is unique to the country and for which it has been baptised the Costa Tropical.
To be precise, the climate is not really tropical but subtropical, since there is none of the stifling humidity common to the tropics. Quite the opposite. Sea breezes fan the shoreline throughout most of the year, tempering the severe summer heat, and there is no rainy season. In fact, it sometimes doesn't rain for many months at a stretch. When it does, it can be torrential and often a year's supply of water will fall in a couple of weeks. But, on average, it only rains 20 days a year. Not a very good reason for bringing your umbrella.
In wintertime, temperatures very rarely fall below 10°C, averaging an impressive 18°C throughout the low season. In summer, this average rises to about 25°C with midday temperatures often well into the 30's.
Temperatures and weather conditions in the mountains can be very different from those on the coast. If you plan to visit Granada or the Alpujarra region, be prepared for it to be either very hot in summer or cold in winter. Mid-season can be a surprising mixture of both extremes, with hot sunshine and cold shadows, so it's best to pack a light jacket. During the winter months you'll need something more substantial.
Sea temperatures are ideal for swimming throughout the summer months but only those in a wetsuit tend to brave the chillier waters out of season. This doesn't stop water sports enthusiasts who can practise most hobbies throughout the whole year, especially sailing and diving.
Unlike most of Europe, winds in this area are only light to moderate when they blow, although occasional gales can sweep the coast during the changing seasons. In the hottest part of summer there's normally a slight sea breeze to take the edge off the extreme heat, especially in the evening when the sun goes down.
The mild climate means that for atleast six months of the year there are normally mosquitoes around. Sometimes they can be more effective at keeping you awake than having a discoteque in the basement. Mosquito nets (for hanging over the bed) are hard to find locally so if you want one it's best to bring it with you. There are, however, an assortment of anti-mosquito electrical plugins available in the supermarkets which vaporise tablets or a liquid. Both are very effective.