Hola
@Ewlodarz So a big welcome to our Camino Forum. You will find lost of good information here and possibly make some good on line friends/amigo (or amigas).
Now for the serious stuff. The weather on the Napoleon section of the
Camino Frances (St Jean to Roncesvalles) can be very changeable, but don't let this put you off,. The small French town of St Jean is a great place to start your camino adventure. If it pans out that the weather forecast is correct (rain/snow/strong winds etc), then there is a plan B - via Valcarlos. This is what I had to do on my camino in May 2017. The first leg to Valcarlos wasn't too bad and the albergue was clean and comfortable (with small lockers beside your bed). The second day does involve a near 600 metre climb to Alto Don Simon. From there its down hill to Roncesvalles.
If I can offer another small piece of advice, be prepared to change your plans. Buen Camino.