Stupid Fuel Gauge!!!!

Just be aware that on the Prius (at least on my Gen3, and I'm presuming on your Gen2 as well), there is no other warning after the flashing pip. That, along with the single beep when the flashing is initiated, is the only prior warning.

Your Gen2's next warning is when the fuel is actually gone and only battery power is left. Though at least that is better than our Gen3s which don't even have that, but only an obtuse different warning when the battery is also drained.

These are not at all like my Subaru, which has multiple stages of low fuel warnings.

Note also that the Gen2 fuel bladder causes greater variability in when the fuel tank actually hits empty, compared to fixed tanks. If you go down there with an frequency, be prepared for greater unpredictability and uncertainty.

 

Exactly same is my experience. However I am unable to understand the exact mechanics of it.

As I understand bladder is a pressurized balloon inside the tank which would occupy the space that otherwise would have fuel vapors, that would thus reduce fuel vapors.
However if that is the case exact opposite should happen. In winter the bladder should have less pressure and thus should allow more gas to be pumped in.

If fuel is inside the bladder with rest of the tank being pressurized , even then it should allow more gas to be pumped in the winter, since it will allow bladder to expand more.

The fact is I can pump in about 2 gallons less in winter. But I completely fail to understand why that happens.

 

Visualize the fuel in a bladder, and no pressure. The goal is to not have any room for vapors.

(Most cars you want to fill up in the morning when the fuel is densest, this car you want to fill up in the heat of the day when the bladder is warmest)