Car is old, 222k miles on it.

I turn the key, and nothing. It's a manual, so if I turn the key and hold it in the "starting" position and take my foot off the clutch, I can hear a relay kick. If I put my foot back on the clutch, I hear the relay kick again.

So I know that's working. But it doesn't try to turn over. It's only sometimes. Most commonly when it's been sitting for a few hours. Before work in the morning or when leaving after work in the evening. If I go to a store, am there for 45 mins and come out, the car will start up fine.

Any ideas? It seems to be happening now with the colder weather.