What am I?

I'm with you some days, but not on the others. I fall short on you always but mostly in summer. What am I?

related riddles

I start with S and end with IT, and have you in the middle. What am I?

I can be found on fingers, in toolboxes and in snails. What am I?

I have no doors but I have keys I have no rooms but I do have a space you can enter but you can never leave what am I