All Camino gear that you take should be both what you actually need, and intend to use. Taking anything you will not use is just carrying dead weight, and should be avoided. Similarly, each item needs to be either multi-functional and as light as you can afford. An ounce or few grams here and there DOES eventually add up to a heavy pack load.
TIP: If you are walking with a companion, consider splitting some items, like first aid supplies or other stuff that can be shared use items. This can reduce individual loads. Why carry two of everything, when one of something will do for the both of you. Just a thought.
My advice is to test pack, based on what you have, and proceed from there. Everything that goes in the pack needs to be judged. Will I really use this, or am I taking it just in case? After two Caminos, I am STILL packing too much. Packing for a Camino is still far more of an art than a science. The forum gives you the chance to cut to the proverbial bottom line without making many of the same poor choices or oopsies as other pilgrims have done.
However, you WILL need protection from rain and likely snow, as late as the end of May, especially at altitudes over about 700 meters. Rain falls year-round. As a general matter, the closer you get to the ocean, the more it rains. On both my
Camino Frances pilgrimages in April-May 2013 and 2014, I experienced more than 20 days or rain and / or snow out of 35 / 34 days that I walked from St. Jean Pied de Port to Santiago.
You will also experience morning temperatures in the low to mid 30s (F) or single digits (C). Combine that with blowing snow or rain, and you have an interesting walking day ahead of you. Plan accordingly.
Also, use the search function above to find useful information about any items you are considering bringing. Virtually EVERY question has been asked before, at least once or a dozen times.
I hope this helps.