HI
I had some onions red barron and a white variaty bought in april to plant straight away. However they were but in a box and only found beginning of aug.
So i planted them anyway.
I have got some that have sprouted and seam to be ok an some were a little 2 dried up and have died.
Now what do i do????? :-\
Take a chance and leave them in, keep them watered, and with a prolong warm spell before the frosts you could get some onions, may be smaller than you wanted but still useable.