The exact time at which an insurance policy expires can differ depending upon state laws and insurance guidelines. In many cases a car insurance policy will expire at 12:01 AM on the expiration date which has caused much confusion to consumers thinking they need to do something by that date, but in reality they need to do it the day before.
If you have not paid on your auto insurance policy by the expiration date it will usually cancel for non-payment. This is often confusing to most people because you expect to have coverage on the expiration date, but in fact usually the policy expires on the first minute of that day. Therefore, you need to get alternate coverage or renew your policy prior to the expiration date.
Some states and/or insurance companies may allow for a grace period but most do not. Thus if you have not paid your insurance payment or obtained insurance coverage elsewhere by your expiration date then you will have a lapse in coverage and need to get it reinstated.
Your policy and/or renewal paperwork should state the exact time. For example I just glanced at my own car insurance renewal statement and it clearly states that if the policy is not paid then it will expire at 12:01 a.m. (one minute after midnight) on the due date.