It is generally not a good idea to use caulking on wood siding.
Caulking cedar lap siding.
Whether you are repainting replacing a window or replacing the siding on your house the caulking around the window trim is a very important element.
The siding expands and contracts with temperature and humidity.
Width is a matter of taste and proper proportion.
If i install a non finished product i usually go with a 3m paintable caulk.
Caulk by its adhesive nature will try to limit this movement leading to widespread failure and cracking in the caulk over time.
Generally we do not recommend caulking butt joints on cedar siding.
The corner boards and the ends of the siding are nailed to the corner studs which anchors the wood for a maintenance free joint.
Corner boards are applied to the sheathing with siding fitting tightly against the narrow edge of the boards allowing for expansion and an adequate caulking bead.
When you try to restrict either it is at your peril.
Think of a wood home as a living thing.
If i am installing a prefinished product which i do mostly i use a color osi match caulk.
It needs to move and breathe.
How to caulk the window trim on lap siding.
Natural siding boards are designed to expand and contract with the elements and we do not want any adhesive to prevent their natural movement.
The answer depends on the manufacturer and installation method used when the siding was first installed.