Every material in a doorway changes size with temperature, and most of the time the amounts are too small to matter. In a valley that goes from single figures overnight to the high thirties by mid-afternoon, they stop being too small. An aluminium frame across a wide opening measurably grows through the day; a steel security door in full sun does the same; and multipoint gear cut to fine tolerances is the first thing to notice, because it needs its bolts to arrive within a millimetre or two of where they were designed to land.
The tell is entirely diagnostic and it costs nothing to check. If a door works first thing and refuses in the afternoon, or works in July and binds every February, the mechanism is almost certainly healthy and the geometry is what moved. People replace perfectly good locks over this constantly, then find the new one behaves identically by the following summer, which is expensive and completely avoidable.
Timber behaves in the opposite direction to what coastal properties experience. Rather than swelling with damp, joinery here dries out through a long hot summer, shrinks, and leaves a door slack in a frame that was tight in winter — so the latch stops seating properly for the other reason entirely. Most of this is adjustment work, which is why a good deal of what we do here is lock repair rather than replacement.