If the IMU was last calibrated in temperature higher than “in the 80’s”. I would suggest doing a recalibration when the drone can be in a cooler location for an hour or so. That way when it’s warmer outside, you will not have to wait as long for the IMU to warm up.
The IMU has some precision accelerometer sensors in it. These need to be at a stable temperature to work accurately. Applying power to them for a few minutes before flight allows their internal temperature to stabilize and achieve full accuracy.