The Environmental Protection Department has rated water quality at 18 beaches 'good', and 15 'fair' for this weekend.

Compared with last week's gradings, Cheung Chau Tung Wan and Silverstrand Beaches were upgraded from 'fair' to 'good'.

Cafeteria Old and Ma Wan Tung Wan Beaches improved from 'poor' to 'fair' while Kiu Tsui, Shek O and Stanley Main Beaches were downgraded from 'good' to 'fair'.

Seven gazetted beaches - Anglers', Approach, Ting Kau, Casam, Gemini, Hoi Mei Wan and Lido - are closed to swimmers year-round because of poor water quality.

Many beaches are likely to be more polluted than their grades suggest during and after periods of heavy rain. Bathers should avoid swimming at beaches for up to three days after a storm or heavy rainfall.

For updates on beach water quality, see the department's website, or call the beach hotline 2511 6666.