Let me first provide a little context by letting you know I am a novice rider and have just over 100 miles on my first road bike.

So I recently put a new tube on my rear wheel (23-622 tires, 16-622 rims), and have spent the last week riding. A few days before Independence Day, I went out of town for about a week for the holiday. When I got back yesterday, I found that my rear tire seemed to be completely flat.

I took the tire and tube off expecting that I had punctured it and it had leaked out over course of the trip. When I had the tube off, I pumped some air into it just to find out where the leak was so I could inspect it. To my surprise, nothing seemed to be leaking at all. I silenced everything around me and listened, but heard no hissing. I left the tube sitting for several minutes, and when I returned it still seemed perfectly fine and aired-up. So I deflated it, put it back on the wheel, and pumped it up again. It seems fine, even after checking it again this morning.

What could have happened to cause the wheel to go flat? My last ride home from work the previous week had a bit of light off-road terrain, but I don't remember hitting any hard bumps or potholes or anything. Do I just have a very slow leak?