NNG - SLRG Open Air Seating

Hi All-
This is my first time posting here, so I'll give a quick intro- I'm normally a die-hard fan of the Santa Fe (especially AT&SF steam), but I've got a soft spot for Colorado narrow gauge, and I spend a bit of time with Microsoft Train Simulator (I'm currently working on passenger cars for the San Juan). My family's making a trip to Colorado, and we had made reservations for coach class on the Rio Grande Scenic railroad for this Saturday. Today they told us that they won't be running any coaches on the train, and we'd have to choose either open-air seating or dome class. Basically I'm looking for thoughts on both, though specifically what to expect weather-wise with open-air seating. Thanks!
-Justin