I'm not convinced that these temps reflect the elevation in the mountains, but these are the temps for the weather station near Venasque France.
History Weather Data Venasque - Synop | Weather2Umbrella LTD
Click on the calendar to switch to Nov 21 - 22, 2020. It was cold overnight and I'm convinced that there would be snow at higher elevations.
I don't think there was any shelter near the Port de la Glere, or in the valley below. She had to complete the hike between the Port de la Glere and the Refuge de Venasque in one day, and she was wise to hope for a Winter Room.
If she was heading to the Refuge de la Glere, that closes in the second week of October.
Accueil, Refuge de la Glère
I really do wonder what she was thinking taking hiking advice from a complete stranger to hike trails and Refuges that close in October due to Winter conditions.