PHILADELPHIA -- The woods were densely foliated, and the sun had reached its highest point of the year, so what Jim Wagner saw last week was absolutely incongruous.
Snow was reported at two Canadian weather stations well south of where it should have been snowing. The morning before, a freezing temperature was recorded in the atmosphere not far above Washington.
Mr. Wagner, a more-than-casual observer given that he is senior forecaster for the government's Climate Analysis Center, said he couldn't recall such a reading so late in June.
They weren't the only indications of a season askew during the first full week of summer. Low-temperature records fell in Atlantic City, N.J., and Wilmington, Del., and from Wisconsin to the Carolinas.
Even the weather map, Mr. Wagner noted, looked a lot like winter.
With the exception of Philadelphia, almost the entire eastern two-thirds of the country has been cooler than average in June, he said. In fact, much of the globe has been cooler.
In the quest for an explanation, the eruption of the Mount Pinatubo volcano in the Philippines has been named as a prime suspect.
It makes sense. Research suggests at least a correlation between volcanic eruptions and cooling, and this was the largest of the century. The aftermath has created a veil in the atmosphere that has reduced the sunlight reaching the Earth.
Last July, a month after the eruption, physicist Paul Handler predicted it would have a significant impact on climate. James Hansen, the NASA scientist who told Congress during the record-hot summer of 1988 that global warming was under way, has said the volcano would postpone the warming.
Mr. Wagner agreed that the volcano could be influencing this summer's weather. "I think we're seeing some of that," he said. RTC "We wouldn't deny that it could be playing a part."
The case for volcanoes causing coolness is more than anecdotal. The most famous example of a possible correlation occurred in 1816, the so-called year without a summer. That season was well-chronicled in a book by oceanographer Henry Stommel and his wife, Elizabeth.
The year before, the Indonesian volcano Mount Tambora produced the biggest eruption on record. The Stommels cited extensive records kept at universities in New England to show that it was an extraordinary summer. Frosts occurred in June, July and August. In June, 3 to 6 inches of snow fell as far south as southern Vermont.