Is it true if you do your calibration in a warm room, say 72 degrees, when you go outside to fly it you have to wait while it warms up? Will it still have to warm up if you did the IMU in a cooler area? Also is it better to calibrate the IMU outside or inside? I only ask this because my IMU required calibration and I did it indoors. Now I have to wait about a minute for it to warm up. That's 1 minute of battery time.

Wow, waiting a whole minute, and life is too short. Haha
Yes, doing a cold IMU calibration will reduce the initial IMU warmup period.
But depending where you live, and the current season of the year, that warmup time might be beneficial.

In the hottest days of summer time, a warmup period, may seem unnecessary. And yes, can be annoying.
On the other side of the flipped coin, during colder times outdoors, this warmup of battery and drone may be helpful.
Where are you located, and is it warm or cooler outside??
It's wise to let your drone hover nearby for a few moments, to check for any erratic flight anomalies and watch for unstable/unusual behaviour.

Unless you are chasing ambulances and fire trucks, a moment to warm up, can be a smart alternative to start up and take off immediately.
If that lost moment of flight time bothers you that much, buy several more intelligent flight battery packs, and stay aloft all day. ;-)

Let your drone warm up, and be happy it has the brains to do it for you. Ha

YMMV


RedHotPoker

The one minute warm up time is fairly typical. I use that time to check my RTH settings, home point set &  wait for it to register a few more satellites, and generally just make sure I'm happy before take off (Memory card in, camera settings done ?). As the motors aren't running the power used is minimal. It does no harm though to check that all is level and undisturbed (no tramping about round the aircraft when IMU calibration in progress) prior to IMU calibration.

Hi Jake, please cool down the aircraft for about 30 minutes, then calibrate IMU in a very level surface, please calibrate it once you turn on the aircraft, and do not move it during the calibration.
You could do it indoors.