For what it’s worth, I have found that flying in around 15 to 18 mph winds, that are directionally consistent while a bit unnerving is relatively safe. It’s when you get gusts higher then 20mph, especially when they come cross stream or inconsistent that things get scary.
I was just doing some work in Sedona AZ yesterday. We had medium to strong winds coming up the valley at around 15 to 20 mph. My P4 did ok, but it was hard keeping the props out of frame due to the angle the drone was holding to keep position. I would get a lot of turbulence when the hot air would gust up off the valley floor, which made for some nerve wracking jumps and dips. Once the gusts jumped up to 20mph, that was it.
Holding steady was near impossible and the drone would bounce around 10 to 15ft in various directions as the gusts came in. Landing was a real trick, basically try to find a tree or wind block of some kind, and slip in next to it between gusts. I guess, I could have tried to hand catch, but given the erratic behavior of the drone, I would more likely have caught a blade then the drone.
So, speed, direction, consistency and gust speed all come into play. 15 to 20mph if consistent is doable, but risky. 15 and below, especially if consistent, and you should be fine. I have seen and heard hirer numbers posted, but I wouldn’t recommend it based on real world experience.