Hi Dave, Also in shady areas during the day. I was walking down the trail last summer, well over 100degrees and was where the sun was shining through leaves creating light and dark spots on the ground. I came within a foot of stepping on a western diamond back. I saw a spot about the size of one diamond that did'nt look right, stopped and looked closer, sure enough the snake was laying on a damp shady spot cooling off from the heat. We both rested for a little while and when the snake crawled back into the salt willows I continued down the mountain. I put this on because they are sometimes hard to see even in broad daylight and you know exactly what your looking for, and right in the middle of your trail. Best wishes and be safe everyone. French