Upvote:4
Under Regulation 261/2004, you're only entitled to a refund if the delay exceeds five hours:
Article 6
Delay
- When an operating air carrier reasonably expects a flight to be delayed beyond its scheduled time of departure:
…
passengers shall be offered by the operating air carrier:
…
(iii) when the delay is at least five hours, the assistance specified in Article 8(1)(a).
(Article 8(1)(a) is a refund.)
Of course, the airline is free to offer other options on top of what the regulation requires to keep a customer happy, but IMHO it's pretty unlikely they would let you cancel for free just because of such a small change (comparable with ordinary operating delays).