Good days for me are high barometric days, sunny, etc.
Bad days for me are low barometric readings and approaching storm systems.

Also anything that affects the feet dramatically. Kneeling bends the toes, and can be horrible the next day. Walking on rocks is bad for me too, and that I cannot avoid, since our summer home is mostly rocks. (We have removed most of the rocks in our paths around the house, but the shore and water all have rocks to deal with.)

Some foods will set me off... MSG containing things. Also too much Tomato sauce, or other histamine containing foods. Nightshade family is sometimes a trigger too.(but not always-- the food thing I think is additive)