Bournemouth, where it's located

The climate of Bournemouth is oceanic, with quite cold, rainy winters and mild, relatively rainy summers.
The city is located on the southern coast of England, in Dorset.
The average temperature of the coldest month (February) is of 4.9 °C (41 °F), that of the warmest month (July) is of 17 °C (63 °F). The lowest record is -13.4 °C (32.9 °F), set in January 1963, the highest is 34.1 °C (93 °F), set in August 1990. Here are the average temperatures.
Bournemouth - Average temperatures
Min (°C)213471012129742
Max (°C)881114172022221915129
Min (°F)363437394550545448453936
Max (°F)464652576368727266595448

Precipitation amounts to 835 millimeters (32.9 inches) per year: so, it is at an intermediate level. It ranges from 50 mm (2 in) in the driest months (May, June, July, August) to 100 mm (3.9 in) in the wettest ones (October, November, December). Here is the average precipitation.
Bournemouth - Average precipitation

On average, there are around 1,765 sunshine hours per year. Here are the average sunshine hours per day.
Bournemouth - Sunshine

The sea temperature ranges between 9 °C (48 °F) and 17 °C (63 °F). So, it never becomes warm for swimming. Here are the average sea temperatures.
Bournemouth - Sea temperature
Temp (°C)1098101114161717161411
Temp (°F)504846505257616363615752


Best Time

The best time to visit Bournemouth is the summer, from June to August, since it is the warmest of the year, although even in this season, it's better to bring a sweatshirt, a light jacket and an umbrella. The month of June is a bit cooler, so you may prefer July and August. September is a good month as well: it's a bit rainier than the summer months, but the temperatures are still pleasant, especially in the first part.
As previously mentioned, the sea is very cool even in summer, however, on sunny days, when the breeze is not too cool, you can sunbathe.