I have land in Northern MI and plant oats in august for a fall plot and this wil be my first year using lime, I am headed up to the property this weekend but dont think I will have time to spread lime and disk it in, is it still worth spreading it now and then disking it in a month when i am up there next or should i just wait and do it all next month.

Isn't lime just water soluble so wont it just dissolve into the soil if it is spread on top

You're right. It is water soluble. The rain willcarryit down into your soil. discing it in only accelerates it getting down to the root zone.