How Luck works

Daily luck:
It can range from -0.10 to +0.10, and is determined completely randomly when you go to sleep. The TV fortune forecaster will give show you one of six forecasts based on where your luck for the day falls within that range.
If your luck is:
-0.10 to -0.07 (Red Skull)
The spirits are very displeased today. They will do their best to make your life difficult.

-0.07 to -0.02 (Bats)
The spirits are somewhat annoyed / mildly perturbed today. Luck will not be on your side.
Note: the choice of phrase doesn't matter. It's just a 50/50 which message you get.

-0.02 to +0.02 (Swirling Lights)*
The spirits feel neutral today. The day is in your hands.

*If 0.0 (no symbol)
This is rare. The spirits feel absolutely neutral today.

+0.02 to +0.07 (Pyramid)
The spirits are in good humor today. I think you'll have a little extra luck.

+0.07 to +0.10 (Star)
The spirits are very happy today! They will do their best to shower everyone with good fortune.


Things affected by daily luck:
Chance ducks/rabbits drop feathers/feet.
Chance of getting extra wood from trees.
Chance of getting coal from rocks.
Chance the next rock you hit in a mine will spawn a ladder (also affected by how many stones are left, and only happens once a level).
Chance two geodes will be produced from the same rock.
Chance of getting an item from trash bins, and the chance the item isn't trash.
Chance your spouse will be jealous after giving a gift to another marriage candidate. (slightly lowers friendship)
Chance of treasure appearing during the fishing mini-game.
Chance of getting higher quality ores and gems from using the copper pan.
Amount of lightning during a thunderstorm.
Chance to double quantity of crops harvested (Sunflowers and those harvested with a sickle not included)
Results from playing slots at the Casino.
Chance of getting Neptune's Glaive (Good early game sword) from fishing treasure chests.

 Added luck from food
Luck buffs given by certain foods is not added to your directly daily luck. It acts as it's own modifier, with whole number values. For example, Lucky Lunch gives you +3 added luck. Buffs do not stack. (There's code to remove buffs from previous food.)** Most things affected by daily luck are also affected by luck buffs from food. Exceptions include: lighting strike checks, chance of getting ore (gems still affected) from the copper pan, and quality drops from ducks/rabbits, which is determined when the day begins (before food can be eaten, and buffs from the night before are reset).
Additional things affected by luck buffs (but not daily luck):
Chance of the Ring of the Warrior and Ring of Yoba buffs activating.
Chance of critical hits on monsters.





















Thanks leddit :^)