Mae'r wybodaeth tywydd a ddangosir isod yn cael ei gofnodi ar wahanol adegau yn ystod pob dydd. I dderbyn rhagor o wybodaeth cliciwch ar un o'r rhagolygon presennol neu ewch i www.bbc.co.uk / weather. Rydym yn ymddiheuro bod y cynnwys hwn dim ond ar gael yn Saesneg ar hyn o bryd.
Ardal Reoli Sirol Gaerfyrddin

Monday at 10:00 BST: heavy rain. 15°C (59°F)
Temperature: 15°C (59°F), Wind Direction: SE, Wind Speed: 16mph, Relative Humidity: 93%, Pressure: 1003mb, falling, Visibility: Moderate

Ardal Reoli Sirol Ceredigion

Monday at 10:00 BST: sunny intervals. 16°C (61°F)
Temperature: 16°C (61°F), Wind Direction: SE, Wind Speed: 18mph, Relative Humidity: 74%, Pressure: 1004mb, falling, Visibility: Very good

Ardal Reoli Sirol Castell Nedd Port Talbot

Monday at 10:00 BST: N/A. 16°C (61°F)
Temperature: 16°C (61°F), Wind Direction: E, Wind Speed: 29mph, Relative Humidity: 90%, Pressure: 1005mb, falling, Visibility: N/A

Ardal Reoli Sirol Benfro

Monday at 10:00 BST: grey cloud. 16°C (61°F)
Temperature: 16°C (61°F), Wind Direction: SE, Wind Speed: 17mph, Relative Humidity: 97%, Pressure: 1002mb, falling, Visibility: Good

Ardal Reoli Sirol Powys

Monday at 10:00 BST: white cloud. 14°C (57°F)
Temperature: 14°C (57°F), Wind Direction: SE, Wind Speed: 14mph, Relative Humidity: 84%, Pressure: 1005mb, falling, Visibility: Very good

Ardal Reoli Sirol Abertawe

Monday at 10:00 BST: N/A. 16°C (61°F)
Temperature: 16°C (61°F), Wind Direction: E, Wind Speed: 29mph, Relative Humidity: 90%, Pressure: 1005mb, falling, Visibility: N/A