No problem with the IMU calibration but I have read a lot of posts about the warm up period. I have a P3P and it was taking a while to warm up. Not a terribly long time, but it did use a few per cent of the battery.

I read many posts about the bird having to be cool because the IMU calibration records the temp at the time of the calibration and makes the bird warm up to that point. I have always calibrated it at home, on a level surface at 70 to 72 degrees. It is usually between 80 and 90 degrees where I live when I go fly. Perhaps because the bird is in the DJI hard backpack it is well insulated and a little cool when I pull it out.

I read about putting it in the fridge for 20 minutes which seems a bit long and could create condensation when you pull it out. I put in the fridge for exactly ten minutes. It certainly felt cool to the touch. I checked in the battery compartment for condensation after a minute or so and it was dry. I also wiped out the compartment. I then did the calibration.

Now, the warming up process takes only a few seconds. From when I start it, check the battery stats and sensor readings, the warming sign is off.

I think it was a useful idea and technique. Ten minutes seemed long enough.

I place mine in the frost free fridge for 15-20 minutes. No harm has come of it. Or out on the balcony in colder temperatures.
Yes, it takes care of the initial warm up period. But it has also helped correct some with a crooked horizon and several other repairs.

There are guys who fly in the rain, against better judgement. So I wouldn't worry about a microscopic amount of ambient air humidity content.
Go fly in the rain forest... Ha

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