I put this instructional pic on my Kitchen Helpers board because so many natural disasters are happening that stop the basics that we are used to, like fresh water, electricity, and the grocery store. Being prepared is a good and necessary thing of today.
Count the finger widths between the sun and the horizon. Each finger is equivalent to fifteen minutes, with each hand totaling an hour. When the sun dips low enough that only two hands fit. Its time to search for a suitable campsite and assemble a shelter.