Europe has put off buying natural gas for the winter in a big, potentially risky bet that the Iran war will be over soon and prices will drop.

The European Union's gas storage facilities are only 65% full, their lowest level toward the end of summer in at least 15 years. Companies have been reluctant to buy gas for storage because they anticipated that Qatar, the world's second-largest exporter of liquefied natural gas, would be able to resume normal shipments through the Strait of Hormuz this year once the conflict dies down.

Now, prospects for a clear end to the war before winter are fading, driving up LNG prices to a 31/2 year high this week. European buyers are being forced to accept more expensive natural gas as the Continent's winter heating season approaches, when gas demand peaks. They are bidding against each other and Asian buyers who are now aggressively locking up supplies.

"Europe is heading into winter with its gas tank at a record low, and the market is priced as if that's fine," said Simone Turri, head of the Western Europe gas desk at MET Group, an energy trading firm based in Switzerland. "Something has to give."

The low storage levels reflect a sharp deviation from Europe's energy security strategy, which was drafted four years ago when Russia's invasion of Ukraine slashed Europe's fuel supplies and sparked an energy crisis. The EU passed rules requiring countries to fill their storage facilities to at least 90% full by Nov. 1, protecting the Continent from attempts by the Kremlin or other adversaries to use gas as a weapon.

But this spring, the European Commission, the EU's executive arm, said member states should aim to fill storage up to 80% rather than 90%, giving them the flexibility to put off some gas purchases with prices surging. At the time, officials were counting on the war to end soon, as President Trump repeatedly said the two sides were close to a deal.

The conflict wore on, however, and navigating the Strait of Hormuz remains fraught. The U.S. and Iran fired on each other this week for the first time in more than a month, while tankers and other commercial vessels passing through the strait continue to be attacked.

Crude-oil shipments have been able to slip through, but only a handful of LNG tankers have exited the strait, according to ship-tracking service Kpler. The Qatari facilities that liquefy the fuel, located in the industrial city of Ras Laffan, are difficult to ramp up and down with every exchange of fire.

Qatar Energy had started to ramp up production during a lull in fighting in June, but backtracked after the two sides exchanged fire again, said Wael Sawan, the chief executive of Shell, which owns 30% of one of the LNG production lines in Ras Laffan.

Both Ras Laffan and the United Arab Emirates' LNG plant on Das Island have been operating for most of the war but at much reduced rates, said JP Lacouture, a natural-gas analyst at Kpler. Thermal imaging shows that six of Ras Laffan's 14 production lines are online, he said.

European gas-storage facilities are spread across the Continent, from tank farms to massive underground caverns. The EU imports almost all of its gas, and the facilities allow countries to build up a buffer for the winter during the spring and summer when gas is usually cheaper. This year, however, gas was more expensive during the summer, creating a disincentive for storage.

Europe is less vulnerable to gas-market disruptions than it was four years ago when Russia launched its full-scale invasion of Ukraine. The Continent's gas consumption has dropped around 20% since then. A major build-out of renewables has lowered gas burned for power generation; factories have either closed or become more gas-efficient; and households have turned down their thermostats.

"The 90% target was made for 2021," said Ben McWilliams, an energy analyst at the Bruegel think tank in Brussels. "It doesn't make sense anymore to fill storage where it used to be."

Gas traders are also anticipating new LNG supply coming online from the U.S., the world's largest exporter of LNG. Golden Pass LNG in Texas is ramping up production and Cheniere Energy is expected to increase production from its terminal in Corpus Christi, Texas.

"Higher prices, Europe's slower storage rebuild and continued geopolitical uncertainty all point to a market that remains precariously balanced," Cheniere Executive Vice President Anatol Feygin told investors last month. "Even if Middle East LNG flows normalize soon, we currently expect Europe to struggle to reach the 80% storage target before the start of winter."

Prices of Dutch TTF gas futures, a benchmark for the region, topped EUR71 per megawatt hour this week, the equivalent of roughly $82, more than doubling this year. Prices are still far below the war in Ukraine crisis levels of 2022.

One big factor working in Europe's favor may be the weather. Meteorologists say Super El Niño-a weather pattern characterized by extremely warm temperatures in the tropical Pacific-has arrived and will stretch into next year. The pattern is expected to result in unusually warm winter temperatures in Europe, which would curb the Continent's gas demand.

Last month's temperature outlook from the World Meteorological Organization "predicts an overwhelming likelihood of above average temperatures across most land areas."