In general, one can say about the climate of the Azores archipelago that it is never really hot and never really cold and that rainfall is more likely between October and March. What is also true in general is that because of the constantly high humidity, the summer temperatures are usually felt hotter than what is actually measured and winter temperatures can seem much cooler as advertised because of the strong winds.
When visiting the Azores, be prepared for unpredictable weather and rapid changes. You could get a nice suntan in Winter lying under the sun in an area protected from the wind. On the other hand, it might be necessary to put on a coat or a jacket to keep you warm at the beach in summer when the sun is hiding behind clouds and the wind is blowing strongly.
The ‘Azores High’ is a subtropical high-pressure area, which is never really located directly over the Azores, but some hundred kilometres north or south. This high-pressure phenomenon was only given this name as a reference point to the nearest populated area. Due to the ‘Azores High’, the weather patterns are very different to those in mainland Portugal. Generally, it is softer and gentler, as is common with subtropical regions. The Azores do not have a Mediterranean climate like the rest of the countries on its latitude; instead it has a humid sea climate. You’ll find that as a result, the Azores are permanently covered with flowers.
Average temperatures in Winter, between December and March, don’t reach below 16ºC. Rainfall, however, increases during these months. In Summer, the daytime temperatures are always around 25ºC (between May and September) and generally won’t reach below 18ºC at night-time.
It all depends what it is you are looking for. With the Azores, all year round is an equally good choice, as the weather is mild and the islands look extremely green and fresh all twelve months of the year. Look out for the special dates for each island as this may add some extra fun and entertainment to your holiday.