The cheapest day to buy gasoline in California has changed, the experts say

The cheapest day of the week to buy gasoline in California — and most other states — is Sunday, says a new report by gas price expert GasBuddy.

The analysis released Feb. 18 was a shift from previous years’ reports, in which Monday was said to be the cheapest day in most states.

“GasBuddy found that Sunday is the most consistently affordable day to fill up in most U.S. states” — 41 states — “while midweek, particularly Wednesday through Friday, tends to be more expensive,” the report said. The data for all states is embedded below this article.

In California, Tuesday is the most expensive day. The difference is generally 4 to 9 cents per gallon, GasBuddy said.

The report noted a sharp and predictable weekly swing in states that follow a pattern of “price cycling,” in which prices consistently are raised on a certain day of the week and then decline before the next spike.

According to AAA, the average price in California as of Feb. 18 for a gallon of regular unleaded is $4.59. Marin County has the highest average in the Bay Area, $4.84, and Santa Clara County the lowest, $4.62.  The national average is $2.92.

The California average is up from $4.21 in January and down from $4.85 in February 2025, AAA said.