I had a need for gasoline in 5°F / -15°C weather. When I pulled up, everyone was complaining that the pumps were unusably slow, just a few hundredths of a gallon per second. After everyone stopped pumping for 30 seconds, the system escaped vapor lock and pumping resumed as normal. Vapor lock implies high volatility gasoline has flashed to vapor somewhere in the suction pumping gas station system. Stopping pumping entirely allowed that portion of the system to cool, so the gasoline went back to liquid.
About 45 seconds into the video, we all stopped pumping, and when the video resumes, everyone is pumping normally.
So in summary, if at a fueling station and all the pumps are extremely slow, suggest that everyone stop for 30 seconds and then try again.
- EPA regulations on summer fuel vapor pressure