Propane inventories and the 5-year average

Propane inventories read against their five-year band are the single clearest signal of how tight or comfortable the market is. Stocks above the band mean the market is well supplied; stocks below it mean supply is tight; and the speed of the move often says more than the level on any one week. This is why a propane site can lead with inventories rather than price, especially in the summer when the price survey is paused and stocks are the live story.

Build season and draw season

Propane inventory runs on an annual cycle. EIA describes an injection season, roughly April through October, when more propane is produced and imported than is consumed and the surplus is put into storage, followed by a withdrawal season through the winter when heating demand pulls it back out. The summer build is the market getting ready for winter. Watching whether that build is keeping pace with a normal year is the whole off-season game.

Why the five-year band is the yardstick

A raw stocks number means little on its own, because propane inventory is supposed to swing hard across the seasons. The useful read is today's level against what is normal for this same week of the year. This site compares each week to the median of the prior five years for that week and labels it vs 5-yr median. EIA's own reports use the five-year average instead. The median is used here because a single unusual year cannot drag it as far, but both are answering the same question: is there more or less propane in the tanks than is normal for the date.

The chart above is US propane and propylene stocks with the historical band behind it. When the line rides above the band the country is carrying a cushion; when it dips below, the cushion is thin.

Worked example: reading today's position

As of the week ending July 3, 2026, US propane and propylene stocks stood at 90.5 million barrels, about 16 percent above the five-year median for the date, which sits near 78 million barrels. That is a comfortable summer position, and a notably full one. Look back at the same early-July week in recent years and the current level is the highest of the set: stocks were near 81 million barrels in 2023 and around 78 million in both 2024 and 2025. The last few years the country has entered fill season with a cushion, and this year the cushion is a little deeper still. That is a description of where the tanks sit, not a forecast of what the price does next.

What days of supply adds

Stocks by themselves ignore how fast propane is leaving. Days of supply closes that gap: it divides inventory by recent daily demand, using the trailing four weeks of product supplied. In the same first week of July 2026, stocks of 90.5 million barrels against demand of about 644 thousand barrels a day worked out to roughly 141 days of supply. Summer days-of-supply figures always look fat because summer demand is small, so the number to compare is not the raw days but how they stack against the same week in prior years.

What the stocks number does not cover

One honest limit: the weekly figure counts primary storage only, the bulk layer of refineries, gas plants, pipelines and terminals. The propane sitting at dealer bulk plants and in the tanks behind houses is invisible to it. In a hard cold snap the retail market can tighten on the ground, with allocation days and stretched delivery schedules, while the national number barely moves. The band tells you about the wholesale system's cushion, not about any one county's delivery week. It also counts propane and propylene together, per EIA's series definition, which is why the pages here say so.

Why stocks can draw in a mild winter

There is a reason a comfortable-looking build can tighten anyway, and its name is exports.

The US is the world's largest propane exporter, and the export pull is the biggest structural claim on the domestic build. In that same July 2026 week, exports ran about 2,616 thousand barrels a day while domestic product supplied was only 525. Most of what the country produces in the summer is loaded onto ships on the Gulf Coast, so national stocks can draw down even in a mild winter if the export pull runs hot. That is why this site watches exports alongside stocks, and why a high inventory number is read next to how fast propane is leaving the country. The export story has its own guide.

The Fill Line reports stocks, days of supply and exports as EIA publishes them and compares them to the prior five years. It describes the position; it does not predict where inventories or prices head next.

The Fill Line is a free weekly read of the public propane numbers. Stocks, the Mont Belvieu spot and the weekly supply balance update year round; the state price survey resumes in October. One email a week on what moved.