I hunt with a flinter during PAs late season (late Dec into Jan). The weather is usually damp and cold. Rain, Snow, etc.. I usually have my lock protected with a silicon treated cloth if its raining or snowing. At the end of the day I just empty the pan and place a piece of folder paper towel between the frizzen and hammer/flint and keep it in my vehicle if I'm going out the next day to avoid condensation by taking into a warm house.
If it rains too bad or is extremely humid or foggy, I usually discharge it at the end of the day. There is nothing worse than a damp charge in a flinter. Especially when you have to remove the barrel, take out the flash hole and pour some FFFFg in, reassemble and hopefully fire it off.
No lower feeling then drawing down on a deer and getting a little puff of smoke and a Ffffffftttt. Use your own judgement. If its damp or wet, discharge your load and when you get home, swab your bore and dry it out. If its nice dry weather, keep it loaded, without an ignition source of course and block your flash hole or nipple with a cloth or paper towel to prevent an accidental firing.