Same here ..............
Our pool has been drained for approx 2 weeks now. It was drained to get the exact measurements for the new liner, and so it was ready for install when the liner came in .
Well , it has been a nasty , windy , rainy 2 weeks here in the northeast and I have been a nervous wreck the old brittle liner would not hold up until replacement time . Its all cracked, and weathered now . Luckily no cracks that are very large or down anywhere near the bottom areas of the pool , just near the top sides. It has been so windy , I have had to go out and stick the liner "bead" back in the coping channel slot quite a LOT , so I didnt loose the whole thing . Now because of all the rain, there is approx 2' of water in the deep end, and that has helped keep things "tight" . I also layed a few large patio stepping stones on the base, in the shallow end to keep everything "snug" until the liner is installed .
Just got a call from the pool co. , and our liner will be installed this upcoming week .

Perfect actually, because the weather forecast says some nice dry days and 80 - 85 degrees. Perfect for a liner install !
I think you will be just fine , unless you get some large tears that will open the base to the weather , or the liner starts pulling out of the channel .
You could always fill a little water (maybe 1'-2' in the deep end hopper) in the pool to keep things tight until the new liner install . I am sure the Pool Co. will smooth the base out just fine before the new liner goes in .
Good Luck !