Natural gas futures on Monday reached their lowest levels since early March as widespread power outages from Hurricane Irene trimmed demand and forecasters predicted cooler weather in many regions.

Natural gas for September delivery settled 7.4 cents, or 1.88%, lower, at $3.857 a million British thermal units on the New York Mercantile Exchange. The September contract expired upon settlement.

Natural gas for October delivery, meanwhile, settled 8.2 cents, or 2.1%, lower at $3.822/MMBtu. The October contract traded at a volume nearly 10 times higher than the September contract.

Both contracts touched intraday lows not seen in nearly six months with September futures dipping as low as $3.834/MMBtu and October's falling to $3.822/MMBtu.

Though Texas continues to be plagued with temperatures exceeding 100 degrees Fahrenheit and above-normal heat is forecast for parts of the Midwest in coming days, market participants are beginning to dial down their expectations that this summer's unseasonably hot temperatures will continue to buoy prices as they have all summer, said Rich Ilczyszyn, senior market strategist at MF Global.

"The market's in a real bearish position," Ilczyszyn said. "It's probably another month before we start talking about cold weather and another 60 to 90 days before we start seeing it."

Indeed, the Commodity Futures Trading Commission reported Friday large noncommercial traders raised their net-short position on the New York Mercantile Exchange by about 1% during the week ended Tuesday. An increase in short positions means more traders are betting prices will fall than are putting money on prices to rise.

Such bets got a boost from Irene, which plowed up the East Coast this weekend, lowering temperatures and knocking out power to as many as 5.5 million homes and businesses. On Monday afternoon, more than 3 million were estimated to still be without power.

Bentek Energy said in a research note that the storm has so far reduced demand for natural gas along the East Coast by about 2.8 billion cubic feet.

The consultancy said prices could continue to see downward pressure if there are "protracted delays in repairing the region's power transmission and distribution infrastructure."

Ultimately, analysts with Canaccord Genuity predict, Irene could be responsible for trimming demand by more than 30 billion cubic feet over the "next couple weeks."