Yeah I rarely flew Ryan Air because of that.. but they didn't have very many canceled flights when I was abroad. My roommates used them all the time and had maybe one canceled flight (and it was like a cheap $30 flight so they just let it go).
Here's their latest policy:
If a Ryanair flight is cancelled and no suitable alternative flight is available, or you have advised Ryanair about your decision not to continue your journey;
we will process a refund of all monies paid in respect of the unused flight sectors on your reservation back to the form of payment used to pay for the original booking.
If you wish to apply for a refund following the cancellation of your flights or if your flight is delayed more than 3 hours and you choose not to fly.
Click here and complete the refund application form.
Ryanair does not provide monetary compensation, pursuant under Article 7 of EU Regulation 261/2004
for flights that are delayed or cancelled for reasons beyond Ryanair's control (extraordinary circumstances). As per the regulation such circumstances may, in particular, occur in cases of
political instability, meteorological conditions incompatible with the operation of the flight concerned, security risks, unexpected flight safety problems and strikes that affect the operation of an operating air carrier.
So... looks like they will refund you if the delay or cancellation is their fault.. but you have to
apply for the refund. BUT if it's anything "beyond their control," which sounds like it includes (hah !) weather issues, then you're screwed without a refund.
source:
http://www.ryanair.com/en/questions/what-happens-if-my-flight-is-cancelled-by-ryanair