"Ysbeidiau Heulog" (pronounced [əsˈbəidia(ɨ) ˈhəɨlɔɡ]; English: "Sunny Intervals"[1]) is the twelfth single by Super Furry Animals.

[1] Rhys has stated that his lyrics are about "looking back at a bad time which had the odd good moment" and that "If there's any song that doesn't sum up [Mwng] it's ['Ysbeidiau Heulog']!

A short bridge plays at the end of the chorus with Rhys singing "Oedd ein cariad ni, heulog tan ddaeth glaw yn llif".

"Ysbeidiau Heulog" was released as a limited edition 7" vinyl single on the Super Furry Animal's own Placid Casual label on 1 May 2000.

[12] Pitchfork Media called "Ysbeidiau Heulog" the best track on parent album Mwng and described it as a "decidedly retro number that combines the swingin' sounds of the '60s with some high-tech vocal effects".

[13] In a 2006 feature on the Super Furry Animals' back catalogue Incendiary Magazine called the track a "clever slice of pop".

[14] In a play on words on the track's meaning in English, Drowned in Sound stated that "Ysbeidiau Heulog" was Mwng's "sunny interval" and wouldn't feel out of place on 1999's Guerrilla.

[15] Both the NME and Rolling Stone likened the track to the work of Roxy Music with the former calling it "happily woozy" and the latter claiming it is a "spunky, sax-spiked bop".