Eastbourne, where it's located

The climate of Eastbourne is oceanic, with quite cold, rainy winters and mild, relatively rainy summers. However, the south coast of England, where Eastbourne is located, has a mild and sunny microclimate, compared to the rest of Great Britain.
The city is located in the south-east of England, in East Sussex, on the coast of the English Channel.
The average temperature of the coldest month (February) is of 5.7 °C (42 °F), that of the warmest month (August) is of 17.8 °C (64 °F). The lowest record is -9.7 °C (31.3 °F), set in January 1987, the highest is 31.6 °C (89 °F), set in July 1976. Here are the average temperatures.
Eastbourne - Average temperatures
Min (°C)435610121515131074
Max (°C)881013161821211915129
Min (°F)393741435054595955504539
Max (°F)464650556164707066595448

Precipitation amounts to 795 millimeters (31.3 inches) per year: so, it is at an intermediate level. It ranges from 45 mm (1.8 in) in the driest month (June) to 105 mm (4.1 in) in the wettest (October). Here is the average precipitation.
Eastbourne - Average precipitation

On average, there are around 1,890 sunshine hours per year; in fact, along with other cities on the south coast of England, Eastbourne is one of Britain's sunniest cities (in practice, it receives the same amount of sun as Milan, Italy). Here are the average sunshine hours per day.
Eastbourne - Sunshine

The sea temperature ranges between 8 °C (46 °F) and 17 °C (63 °F). So, it never becomes warm for swimming. Here are the average sea temperatures.
Eastbourne - Sea temperature
Temp (°C)98891113151717161311
Temp (°F)484646485255596363615552


Best Time

The best time to visit Eastbourne 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.