Some of us can't move all our plants inside in just one afternoon when weather threatens. It's good to learn which ones are most tender, so we can focus on those, leaving the hardier ones for later.
Most Cattleya hybrids easily tolerate a night or two in the low 40s F / 4-6C if dry at the time, and it's warmer the next day. Some species Cattleya and related genera tolerate light freezes if dry.
running "Cats" cold
Cold? Something to think about.
Can orchids get too cold?
Do "CATS' go dormant?
What survived the cold?
Cattleya night time temps in California?
But not all.
Cattleya lueddemanniana temperatures?