My Mini 4K is rated ‘wind level 5’, which equates to Beaufort Force 5, 24mph/38kph. I don’t go out with the drone if the forecast is for more than this, and by forecast I mean UAV Forecast app, which gives the wind gust speeds at different heights.
Of course, that doesn’t prevent me being caught out by higher winds than have been forecast, especially gusts around buildings, cliffs, being funnelled through narrow gorges &c. You develop a sense of what the wind is doing and how your drone will cope with it from flags, tree movement/noise, and such, but conditions 400’ up can be very different to what you are experiencing standing on the ground. The screen will warn you if your drone is struggling to hold position or is unsteady, and I have found when this happens that coming down 100’ or so solves the problem; I haven’t had to pack up and go home because of it yet.
The situation to avoid at all costs is where the drone cannot make headway against the wind and is being blown away from you, perhaps over water, a motorway/railway, or dense forest. If you are worried about wind and especially it increasing in strength, good airmanship is to fly the early part of the mission against the direction of the wind, then, should conditions deteriorate, you will be able to RTH with the wind behind you. Come home earlier than you normally would, because the knocking about the drone is getting will drain your battery quicker than normal as it constantly tries to correct itself
As for Relative Humidity, something else that UAV Forecast predicts, I used to worry about damp getting inside the drone and causing short-circuits, but I don’t any more because it’s quite warm in there… Don’t land in wet grass, though! What is worth looking out for is humidity in cool weather, when the windchill effect at the fast-moving prop tips can cause icing. You will not be aware until the warning comes up ‘propeller not spinning freely, land immediately’, and it will be a matter of luck if this is not already too late, especially if you are some distance from Home Point.
Flying in rain is not generally recommended, but, again, you can be caught out. The worst is drizzle or mist/fog, fine droplets that will insinuate themselves inside the drone and cause havoc; this is more dangerous than a heavy downpour. Avoid sea spray, as insidious as drizzle but with a corrosive element for even more fun… If you’ve got Mr Drone wet, turn him off & remove his battery as soon as you can, then dry him off and carry a silica gel bag to put inside him until you get home, then dry him out thoroughly on a radiator or in front of a heater.
I don’t know what happens if a drone is struck by lightning, but I suspect you’ll find it has become a paperweight with a story to tell, if there’s anything left to recover. I might be being overcautious, but I don’t fly if there’s a possibility of lightning strikes. I use an app called ‘My Lightning Tracker’ set to a40-mile radius of my position.
A general rule in poor weather is to keep close and upwind of your home point. I have obtained steady footage in wind conditions that the drone was struggling with and you could see it being tossed about; DJI gimbals are awesome!
