Many people in the fall are faced with the prospect of putting covers on in less than ideal weather. As long as the temperature is cold, everything stays quite taunt. As the temperature eventually starts to warm up, you will be faced with the inevitable wrinkles. You will need to tighten the cover to prevent premature wear due to flapping in the wind.
Tightening does not have to be done all at once. You can do half one day and half on another. It is important to remember that you are always pulling at 90 degrees to the wrinkles. Most of the tightening will need to be done lengthwise first.
If you have a loose cover and no time this week to tighten things, there is a temporary fix! Take a soft length of rope (do not use nylon!) and throw it over the building where the cover is particularly loose. Tie the rope off at the base as tight as you can.