US Gas Gauge
Guide · Seasonality

Seasonal gas price patterns explained

Month-by-month price patterns for the U.S. and the nine states the EIA surveys weekly, measured over 22 full years of data, and how the regional seasons differ.

· sources cited below
How it is measured

The national pattern

Gas prices move for many reasons at once, and most of them have nothing to do with the calendar. To isolate the part that repeats each year, this guide takes the EIA’s weekly retail price for regular gasoline, averages it by month, and divides each month by the average of its own year. A value of +5% means that month typically ran 5% above its year’s mean. Averaging those ratios across the 22 full years from 2004 to 2025 removes the long-run trend and most one-off shocks. 2004 is the first full year for which all nine weekly-survey states have data, so every area here is measured over the same years.

For the U.S. average, the low comes in January (−9.1%) and the high in June (+6.3%), a typical swing of 15.4 pts. On a $3.50 annual average, that is roughly $0.54 a gallon between winter and early summer. Prices stay above the annual mean from April through October and below it from November through March.

U.S. regular · avg. % above / below each year’s own annual average
Above the year’s averageBelow

Source: U.S. Energy Information Administration weekly retail price of regular gasoline (all formulations), U.S. average. Each month is its average across 2004–2025 after dividing by that year’s own annual mean.

State by state

Same season, different sizes

The same calculation for each of the nine states the EIA surveys weekly shows a shared shape with real differences in size and timing. 9 of the 9 bottom out in January and 9 peak between May and July. The table shows every month, ordered from the largest swing to the smallest.

AreaJanFebMarAprMayJunJulAugSepOctNovDecSwing
U.S. average−9.1−7.3−1.9+1.6+5.1+6.3+5.4+4.4+3.7+0.9−2.8−6.315.4
Colorado−12.4−9.4−3.90.0+4.3+7.6+7.9+7.0+7.4+3.0−2.8−8.720.3
Washington−11.1−10.0−3.8+0.6+5.4+6.7+5.8+5.3+5.2+2.8−1.2−5.717.8
Ohio−9.0−7.2−1.8+1.2+6.1+7.9+5.4+4.6+3.3+0.1−3.6−7.017.0
Texas−9.3−7.4−1.2+2.8+5.6+7.0+6.4+5.0+3.40.0−4.6−7.716.3
Minnesota−9.7−6.9−1.4+0.4+4.8+6.3+6.0+5.6+4.6+1.0−3.4−7.416.0
California−10.4−7.3−0.7+2.5+5.3+5.3+4.1+2.6+3.1+3.2−1.4−6.315.7
Massachusetts−7.7−7.2−4.0−0.8+4.7+6.4+5.9+4.8+3.8+0.2−2.1−4.114.1
New York−7.0−6.4−3.10.0+4.3+5.1+4.9+3.9+3.2+0.2−1.5−3.612.1
Florida−7.0−5.8−0.6+2.7+4.2+4.7+4.1+2.7+2.9+0.2−3.0−5.011.7

Percent above (red) or below (green) each year’s own average price, averaged over 2004–2025. Swing is the highest month minus the lowest, in percentage points. EIA weekly retail regular, all formulations.

Colorado has a swing of 20.3 pts, the largest of the nine. Its September index is +7.4%, against +3.7% nationally, the highest September figure in the table, so its summer prices last longer than in any other surveyed state. Its January low is −12.4%, the deepest winter trough of the nine. The survey data show the pattern but do not identify its cause.

Florida sits at the other end, with a swing of 11.7 pts, the smallest in the table. Its January low is shallow (−7.0%) and its peak is modest (+4.7% in June). New York is similar, at 12.1 pts. Washington, by contrast, has one of the deepest winter troughs, −11.1% in January, and a swing of 17.8 pts.

The Gulf Coast and Midwest states sit between those extremes. Texas peaks in June at +7.0%, Ohio in June at +7.9%, and Minnesota in June at +6.3%. The direction is consistent from year to year even where the size is not. In 17 of the 22 years, the U.S. average in June was above that year’s mean; in January it was above the mean in only 1. The exceptions are years when crude oil moved far enough within the year to override the calendar, such as 2008, when prices peaked in summer and then fell by more than half before December.

California differs in timing rather than size. Its swing, 15.7 pts, is close to the national figure, but its high season ends later, and it is the only area in the table where October averages as high as or higher than September: +3.2% in October against +0.9% for the U.S.

The reasons — attributed to sources

What drives the calendar

The patterns above are measured from EIA price data. The reasons below come from the EIA and state regulators, and each is cited. Our price data alone cannot separate one cause from another.

Spring: maintenance and the summer blend. Refiners schedule most planned maintenance for late February and March, which reduces output just as prices begin to climb in the table. [2] In the same months they switch to summer-grade gasoline, a lower-volatility blend that the EIA says costs several cents per gallon more to make. Federal rules require it at terminals from May 1 and at retail stations from June 1 through September 15. [1] The mechanics of the blend itself are covered in our explainer on summer and winter gasoline.

Summer: demand. Gasoline consumption rises with summer driving, and the EIA notes that higher summer demand generally raises prices. [3] In the table, every area sits above its annual mean from May through September.

California’s later switch. California sets its own fuel rules. Refiners there must produce summer-blend gasoline through October in most of the state, and winter blend is allowed only after October 31. [4] The national switch is allowed after September 15. That six-week difference lines up with California’s October index staying at its September level while the national figure falls.

Late summer: hurricane risk. The Atlantic hurricane season runs from June 1 to November 30, and Texas and Louisiana hold 48% of U.S. refining capacity, so a Gulf storm can cut supply for the whole country. [5] These events are too irregular to show in a long-run average, but they are visible in single weeks. The national average rose 46¢ in the week to September 5, 2005, after Hurricane Katrina, and 28¢ in the week to September 4, 2017, after Hurricane Harvey took about 3.9 million barrels per day of Gulf Coast refining offline. [6]

Fall and winter. After mid-September, the cheaper winter blend returns, driving falls off, and prices drift down through December and January. The national index falls from +3.7% in September to −6.3% in December.

Reading it correctly

An average, not a forecast

The index describes the typical year. Any single year can depart from it when crude oil moves sharply. In 2008 prices fell steeply in the fall as crude collapsed; in 2020 they dropped in the spring, when the index says they usually rise; in 2026 they rose sharply in March. The seasonal pattern is best read as a direction that holds when nothing larger is happening. For the current outlook, which combines this pattern with the EIA’s forecast, see the gas price forecast.

Common questions

Seasonal prices, answered

What month are gas prices usually lowest?
In EIA weekly data for 2004–2025, the U.S. average was lowest relative to its own annual mean in January, at about −9.1%. 9 of the 9 states EIA surveys weekly share a January low.
What month are gas prices usually highest?
The U.S. average peaks in June, about +6.3% above the year's mean, a swing of 15.4 pts from the winter low. Individual states peak between May and July.
Which state has the biggest seasonal swing in gas prices?
Among the nine states with weekly EIA data, Colorado has the largest average swing, 20.3 pts from its January low to its July high. Florida has the smallest, 11.7 pts.
Sources

Where the causal claims come from

  1. [1]U.S. EIA, Today in Energy — “Date of switch to summer-grade gasoline approaches” (Apr 29, 2013): summer-grade gasoline, its cost, and the federal switchover dates
  2. [2]U.S. EIA, Today in Energy — “Reduced refinery activity puts upward pressure on gasoline and diesel prices” (Mar 6, 2024): planned maintenance peaks in late February and March
  3. [3]U.S. EIA, Energy Explained — “Factors affecting gasoline prices”: seasonal demand and regional fuel requirements
  4. [4]Office of the Governor of California, letter to the California Air Resources Board (Sep 30, 2022): summer-blend required through October in most of the state
  5. [5]U.S. EIA, Today in Energy — “Forecast strong hurricane season presents risk for U.S. oil and natural gas industry” (May 22, 2024): June 1–November 30 season; Texas and Louisiana hold 48% of U.S. refining capacity
  6. [6]U.S. EIA, Today in Energy — Hurricane Harvey refinery outages (Sep 2017): about 3.9 million barrels per day of Gulf Coast capacity offline at the peak

All monthly indexes and weekly moves are computed from the U.S. Energy Information Administration’s weekly retail series held in our database.

Explainer
Summer vs. winter blends →
Guide
History of price spikes →
Outlook
Gas price forecast →