Thats better than licking your finger and sticking it up in the air.... what has almost brought me unstuck on several occasions is how much higher the wind speed can be when you uncrease in altitude.
That's definitely true. I use mine as a rough guide only. If it feels windy I use it to check speeds and especially gusts. If it's gusting above 15 or so, then I would be less inclined to fly. I generally double mph at altitude.
I've also found that I usually overestimate wind speed when I just guess versus using a wind meter.