How did my candle wax crawl up the sides of the jar?

Candle wax expands considerably when hot and molten. So while burning the candle the level in the glass rises.

But when the candle is extinguished the outer region (nearest the glass) cools down quicker (candle wax doesn't conduct heat very well) and solidifies first, becoming immobile. The molten remainder then shrinks before solidifying.

So it's the temperature gradient (from outside to inside) and the preferential solidifying from outside to inside that causes the outside material to be higher up in the glass, after full solidification.

Here's a corroborating experiment almost anyone can carry out. Allow a cup candle (even a small tealight candle will work) to burn for a sufficiently long time, so a large molten puddle has formed. Now gently extinguish the flame and allow the candle to cool down and solidify undisturbed. The originally flat solid surface will have become convex.

Yeah, I would guess that the alternate heating/cooling of the wax in the sun pushes it up the side of the glass. Presumably the surface tension between the wax and the glass is quite strong and holds the wax up once it's been pushed up. Subsequent cycles cause wax to "backfill" the wax that's been pushed up.

It would be interesting to design an experiment to learn more about the characteristics of the process.

The energy comes from the sun, that much is certain.

One possible mechanism is capillary action resulting in a meniscus, assuming the sun heats the wax to a (near) liquid state.

The other possible mechanism is a vaporization/redeposit cycle. During the day, heat from the sun creates wax vapor, which is heavier than air ^{[citation needed]} and therefore stays within the confines of the jar. At night, when the jar cools, the wax vapor is deposited on the sides of the jar.