Circle K’s National Fuel Day is Thursday, May 7 – the day the gas station offers customers 40 cents off per gallon between 4 p.m. and 7 p.m. Members of the chain’s Inner Circle loyalty program can start early from 12 p.m. until 3 p.m. National Fuel Day comes as gas prices skyrocket, with Nevadans paying an average of $5.56 per gallon in Washoe County and $5.29 in Clark County, according to AAA.