Another possibility is that the rubber gasket around the door is pressing too tightly on the door. The additional friction may be fooling the control into thinking the door is hitting something.
Normally, the garage door gasket is screwed to the wood framing around the door, and as that wood framing swells and shrinks with seasonal changes in humidity, the gasket can press more tightly or with less pressure on the door.
Try this: Every pharmacy sells glycerine. Glycerine (or, more correctly "glycerol", cuz it's an alcohol)(see note below) behaves very much like a very light oil. It's about the same consistancy as WD40. However glycerine is just like water in that it evaporates completely without leaving a residue behind like WD-40 does. That way, if it turns out the glycerine does nothing to help, you can just give it some time to evaporate rather than cleaning the stuff off. Also, glycerine is completely soluble in water and vice versa.
And, knowing that about glycerine is a helpful tip to DIY'ers. If you ever want to fit tightly fitting parts together, without being concerned that any oil you use is going to collect dust and screw things up in the long run, use glycerine as the lubricant. Once things are assembled, the glycerine will evaporate completely without leaving a dust collecting residue behind like an oil would.
So, open the garage door and wipe some glycerine on the surface of the rubber door gasket that rubs against the garage door. That will provide lubrication between the two surfaces so they slide more easily over one another rather than rub.
If the problem goes away for a while until the glycerine evaporates, then the glycerine test will reveal that the problem is excessive friction where the rubber meets the steel. In that case, you just need to loosen the door gasket screws a bit until the cooler dryer weather returns, and your lumber shrinks a bit.
Don't put oil or grease on the door gasket because airborne dirt and dust will stick to it, making the oil or grease gritty and gradually scratching up the door paint.
(and you don't need to know this)
Anything with a hydroxyl group (-OH) bonded to a carbon atom is called an "alcohol". So, water (H-O-H) is NOT an alcohol. It's gotta be a carbon atom. Methanol, H3C-OH is an alcohol. Glycerine, on the other hand, looks like this:
So, glycerine is an alcohol three times over cuz it's got three -OH groups, all of which are bonded to carbon atoms. So it's correcter to call it "glycerol".
Some day you could be on a TV game show and really need to know this.