The chill of autumn air has already descended upon Wisconsin, and the month of October is off and running. But statistics have recently arrived about the summer season, and for many parts of the United States it was a sizzling summer.

From a meteorological standpoint, the summer season is June, July and August. The fall season starts Sept. 1. That helps keep weather statistics a little more orderly. Astronomically speaking, fall begins around Sept. 21 or 22 each year, when the Sun is directly overhead at the Earth's equator.

In the lower 48 United States, the summer of 2001 was the fifth warmest on record according to scientists at the National Climatic Data Center (NCDC) in Asheville, N.C. The month of August was the fourth warmest in written records. Summer weather across the U.S. has been warmer-than-normal in 11 of the past 15 years. This trend alone has sparked debate among long-range weather scientists, or climatologists, regarding global warming.

Reliable weather records in this country reach back about 100 years or so. Compared to the life of the planet (4.6 billion years), that is a very short time frame. Even within the most recent 100-year period, temperature records can be suspicious. The quality of thermometers has improved recently, and the number of data recording locations has increased as the population has increased. Larger population means growing urban areas, which means more concrete, asphalt, buildings, etc. to add to the urban heat island effect. Is our national warming trend due to increased greenhouse gases, or is the urbanization of America adding to the greater warmth?

One of the problems with looking at climatological trends is the near-term perspective. We really need to step back and look at weather records over several centuries to start to see trends. Global warming really took off with the industrial revolution.

The 1930s and 1950s were warm decades, and the dust bowl days of the '30s in the central and southern Plains are testament to the drought conditions. But the 1960s and even part of the 1970s were cooler than normal, prompting the publication of several books outlining the upcoming ice age. The most recent ice age ended a mere 10,000 years ago, not a long time compared to the history of our planet.

Is this recent warming of the 1980s, 1990s, and so far this century a real footprint for global warming due to increased greenhouse gases, or is this just a blip in the long-range temperature trend? Get 10 climatologists in a room to discuss this and you'll probably get a split decision. And now so much of this discussion has become political. The economic impact on imposing climate controls on industry is a part of the global warming debate.

In the short term, most people around here just want to enjoy some beautiful autumn weather. We all know that soon enough the falling leaves of October give way to the falling flakes of winter.

Watch Vince Condella on Fox 6 Sunday through Thursday at 5, 6 , 9 and 10 p.m. You can see the FOX 6 weather forecast around the clock at www.fox6milwaukee.com