The question is really what you mean by sunny weather conditions ?
Does it means the weather is hot or does it means the sun is shinning ? Because in winter, you can have a beautiful sunny sky and extremely low temperatures altogether. For instance in winter you can have 40°F in the resort and 0°F at high altitude.
In my opinion the relevant question is wether it will be hot or cold !
If the weather is cold then you definitely need warm clothes, and as other members have already said, hardshell is really useful against the cold wind.
Don't forget that a significant part of your time will be spent doing nothing on the skilift, exposed to wind and cold seats.
If the weather is hot then this is becoming problematic, because you'll be very hot doing a sport with a hardshell in these conditions. I have ever skied in April under hot conditions, and clearly shorts and T-shirt were sufficient.
But there are 2 issues when it is hot:
- snow is wet, if not small ponds everywhere
- falling onto bare skin hurts a lot
So as a beginner, I assume you'll fall quite a few times, and get very wet, so water-resistant clothes are definitely a plus (if you wear jeans for instance, they will be wet quickly and will keep this way all day long).
Also to avoid being burnt or tear your clothes apart when falling it is better to have clothes made with solid tissue. The ideal would be to have some hardshell clothes without warm padding.