Santa Maria, where it's located

The climate of Santa Maria is temperate oceanic, with mild, rainy winters and pleasantly warm summers.
The island is located at the 37th parallel and is the most south-eastern, and the least rainy, of the Azores islands. The highest peak on the island is the Pico Alto, 587 meters (1,925 feet) high.
The average temperature of the coldest month (February) is of 14.6 °C (58 °F), that of the warmest month (August) is of 22.9 °C (73 °F). Here are the average temperatures.
Santa Maria - Average temperatures
Min (°C)131212131416192019171513
Max (°C)171718181922242625232018
Min (°F)555454555761666866635955
Max (°F)636364646672757977736864

Precipitation amounts to 775 millimeters (30.5 inches) per year: so, it is at an intermediate level. It ranges from 20 mm (0.8 in) in the driest month (June) to 100 mm (3.9 in) in the wettest ones (January, November). Here is the average precipitation.
Santa Maria - Average precipitation

On average, there are around 1,930 sunshine hours per year. Here are the average sunshine hours per day.
Santa Maria - Sunshine

The sea temperature ranges between 18 °C (64 °F) and 23 °C (73 °F). The sea is never very warm, though it is warm enough for swimming from July to October. Here are the average sea temperatures.
Santa Maria - Sea temperature
Temp (°C)181818181920222323232119
Temp (°F)646464646668727373737066

Santa Maria

Best Time

The best time to visit Santa Maria runs from June to August, since it is the warmest and the least rainy period of the year. In May, you can go, but cool and rainy days are a bit more frequent.
Even in summer, it's better to bring a sweatshirt, and maybe a light jacket for the evening.