Late season skiing is decided by altitude, so make height your first and most important filter. A glacier is the only true snow guarantee, which is why Zermatt, Tignes, Saas Fee, Les Deux Alpes and Cervinia sit at the top, skiing reliably into spring and in several cases through summer. After the glaciers, the highest resorts such as Val Thorens, Val d'Isere and Obergurgl hold snow far better than lower terrain even without one.
Plan your days around how spring snow behaves. South facing pistes turn to perfect corn snow in the morning and slush by afternoon, so start early and follow the shade as the day warms. On the glaciers the snow stays cold and firm longest, so they are where the best surface lives late in the season. The trade off is that glacier terrain is often gentler, so thrill seekers should pair a high resort with guided off piste while the snowpack is stable.
Match the base to the rest of your trip. Zermatt and Val d'Isere offer top villages, Cervinia and Les Deux Alpes add value, Solden brings the party and Saas Fee the scenery. For a country by country view, see late season in Italy, late season in France, late season in Switzerland and the broader late season in the Alps.