By Heather Brown  

MINNEAPOLIS (WCCO) – Over past weeks, we’ve seen gas prices jump about 15 cents. In Minnesota, it went from $2.62 to $2.79 since April 7, which is normal this time of year. Part of that jump comes from the annual switch to a different kind of gas.

So what exactly is a summer gas blend? Good question.

It happens almost every April and this one is no different.

Gary DeRusha is the operations manager at the Eden Prairie Bobby and Steve’s.

“We’re not too cold and we’re not too hot, so this is the perfect time to get their maintenance done,” DeRusha said.

But something else is happening now, too. The gas you put in the car in the summer is different than the gas in the winter.

“The difference between a winter blend and summer blend is what they call, we’re not going to be rocket scientists here, but it’s called Reid vapor pressures – RVPs,” DeRusha said.

RVP is a measure of how easily the fuel evaporates into the air and the EPA regulates its levels. It’s higher in the winter blend and lower in the summer, which means less evaporation and fewer emissions.

“In the summertime when the heat is higher, that contributes to the ozone layer, unhealthy air,” DeRusha said.

Experts say the summer blend costs refineries between 5 and 10% more.

The EPA requires refineries to have the summer blend in their system by May 1 and all the gas stations to have it by June 1. Because the process of getting gas to the station takes a while, the transition starts in early spring.