Overview: BrightonBrighton (United Kingdom) in general has a mild climate. Temperatures during the day are in the range from 8 °C (46 °F) in January to 22 °C (72 °F) in July. Sea temperatures are in the following range: 8 °C (46 °F) in March to 17 °C (62 °F) in September. The least rainy month in Brighton is June with its 8 days of rain, the rainiest month is January, when it rains 13 days. Temperatures during the night go from 2 °C (35 °F) in February to 12 °C (54 °F) in July.