| | Re: How fast does gas evaporate? Overnight???
I think that speed of evaporation is very believable. Of the factors, temp is perhaps the least important, as long as it is not seriously cold, then humidity and wind. Not mentioned is surface area (of the gasoline) which is exposed to the air and wind. Think 6 oz. of gas in a narrow necked Coke bottle, versus the same 6 oz. in a normal, wide topped water glass. If your container had a fairly wide top, I'd think the "disappearance" you are reporting can definitely be evaporation.