Look for the clues!Earlier this morning I sat outside with a mug of @explorercoffees under a clear sky. As I contemplated routes for a hike up into the mountains I spotted two jets crossing the sky, each leaving a vapour trail.Vapour trails indicate moisture, giving us a clue that the weather conditions could well change.Sure enough, two hours later cloud had moved in and dropped a shroud over the mountains (second image two hours after the first).Whether you’re trying to read the weather of practicing the science of navigation, look for as many clues as you can find to help validate or confirm your thoughts. Each clue is like a piece of a jigsaw puzzle that you can use to build a complete picture.