On Sun, 23 Aug 2015 12:17:00 +0000, AnthonyL wrote:

In one tropical country I go to the locals insist on filling up at the
garage first thing in the morning to ensure that they get maximum mass
for the delivered volume. The reasoning is that as the day warms up the
density decreases. Any truth in that?

shrug Just about any solid or liquid changes in volume as the
temperature changes.

But fuel is stored underground before sale, so the storage temperature is
going to be fairly consistent.