Had lunch indoors yesterday and it was cold inside. Even the waiter had his hands in his pockets with heavy clothing. What is going on?

Well a few days ago the plastic was up on the patio but no propane in the heaters. So it's cold outside and inside.

It is really cold outside, and that cold goes inside through transitive properties and when the door is opened. The only way to counteract this is by filling the inside with heated air. It is very likely that the inside cooled down a lot between the close of business on previous night and lunch the next day assuming they didn't leave the heater on full blast. That means the first to arrive for the lunch shift had to engage the heater, and depending on the amount of degrees and space to heat, it can take hours before returning to 70ish inside. Keep in mind they're trying to reheat all while it is still cold outside and people keep coming through the doors. So I'm going with two factors: 1. The heater is not powerful enough for their space to do a quick heat up. 2. The manager did not properly plan around the temperature drop with said weak heater. It's also possible that they're trying to save money by not running the heater 40 degrees above the outside temperature.