Walk Without Rhythm (to avoid the Worm)

Telecanter has a very nice simple mechanic for weather and survival here. 

Copying it in full: "Each hour you're in distress, roll under your Constitution or take 1 point of damage per level."

I'm going to modify this a little bit, as Telecanter suggests, to account for the weather-specific needs of Legacy of the Bieth. So what are some of the conditions where weather causes distress around Sanctuary?

In the scrublands, it's rocky terrain with scrub brush and other light vegetation around. You don't need to worry about distress unless a weird storm comes up. Folks wearing heavy armor make distress rolls every 4 hours, generally.

In the deep desert, characters will generally make one distress roll if active during the heat of the day. Characters in heavy armor will make one distress roll an hour. Fighting or other strenuous activity will increase these rolls, to one an hour (normal) or one a ten-minute turn (heavy armor).

Being near a Zone anomaly may result in severe distress - all characters in proximity make a distress roll every round.

Lost in Maroc, Greg Slick
See here