I've had several close calls when flying far away over water and returning against strong head wind, so it finally dawned on me that, since my love for adventure and risk is not going away any time soon, I've better have a handy calculator spreadsheet that will rein in my excitement with estimates more precise than my intuition provides (my intuition is heavily biased towards optimism). The spreadshet I've attached is a simple tool where you input two variables (distance from home and speed at which the drone returns home) and you get a few estimates of when to start returning home. Nothing fancy. You need to test for the actual speed at which the drone returns and input that into the calculation. Wind is usually faster the higher up you go, so descend as you're coming back home. A corollary is that if your RC happened to die on you at a moment when you're counting on returning close to the ground, you're probably not going to get the drone back, as it would first go up to RTH height and fight the stronger wind up there all the way back. (Not that I take into account this risk, as I've never had the RC completely die.) Hopefully you're one of those conservative people who would never fly in strong wind, but if you're like me and can't resist the lure of adventure, having this spreadsheet two taps away on your phone could mean the difference between driving back with a drone and driving back with just a lone RC. You can download Microsoft Excel for free on iOS and Android. And if you ever wondered, no, the Phantom doesn't take into account wind speed when calculating low battery RTH. Too bad. It wouldn't be too difficult to give the pilot a rough estimate of wind speed.