I check PSI every time coming out of storage, and before every trip. I would not expect 3 PSI loss over that time, all other things being equal, but other things are not always equal.
I can put it away in March at 80 PSI and pressure may be 83 PSI when I take it out in June. Put it away at 80 PSI in September, it may be 77-78 when I take it out for a Thanksgiving trip, or less than 75 mid-winter. Change in cold inflation pressure thus depends on what temperature "cold" was when pressure last adjusted, and what that temperature is when next checked.
I also check pressures at the beginning of each driving day. For that, I don't expect to see significant changes, which mean trouble.