Or, easier is to download the Buen Camino app. On the page listing accommodations for each town you can see right away which ones are open year round. Here's the page for Negreira - I've put a red check mark next to those open all year.
Aplicación del Camino de Santiago profesional, con mapas, perfiles, alojamientos, planificador de etapas, a pie o en bici (Btt), en idiomas y actualizada.
This site is run by Ivar at in Santiago de Compostela.
This site participates in the Amazon Affiliate program, designed to provide a means for Ivar to earn fees by linking to Amazon