I recently spent 5 weeks in the Kuwaiti desert and my watch of choice was an Observer model, I can report that the watch survived admirably in all fields of form and function, having dealt with high temperatures during the day, cold at night, dust storms and very abrasive conditions. I can also say that this has some of the best luminous qualities I have found in any watch I have owned including some particularly high end watches. The nights at this time of year are particularly long and anyone who has been there will tell you that when it gets dark out here it is like the lights being turned off, the Observer remained visible at all times through out the night.