This excerpt taken from the WM 10-K filed Feb 16, 2010.
The seasonal nature of our business causes our quarterly results to fluctuate, and prior performance is not necessarily indicative of our future results.
Our operating revenues tend to be somewhat higher in summer months, primarily due to the higher volume of construction and demolition waste. The volumes of industrial and residential waste in certain regions where we operate also tend to increase during the summer months. Our second and third quarter revenues and results of operations typically reflect these seasonal trends. Additionally, certain destructive weather conditions that tend to occur during the second half of the year, such as the hurricanes generally experienced by our Southern Group, actually increase our revenues in the areas affected. However, for several reasons, including significant start-up costs, such revenue often generates earnings at comparatively lower margins. Certain weather conditions may result in the temporary suspension of our operations, which can significantly affect the operating results of the affected regions. The operating results of our first quarter also often reflect higher repair and maintenance expenses because we rely on the slower winter months, when waste flows are generally lower, to perform scheduled maintenance at our waste-to-energy facilities.
For these and other reasons, operating results in any interim period are not necessarily indicative of operating results for an entire year, and operating results for any historical period are not necessarily indicative of operating results for a future period.