Odd weather of ‘93 persists with early frost, cool temps

By Michael McVey

It was only two weeks ago that autumn officially started, but cool temperatures and early frosts have ushered in the colors of fall with changing leaves and warm jackets.

The average high and low temperatures in Rockford last month were 67.8 and 48.9 degrees, 4.7 degrees below the average for September, according to Ron Fields, forecaster at the National Weather Service in Rockford.

Since the warmest day was 83 degrees on Sept. 12 and a freeze occurred on Sept. 30, the abnormally cool temperatures were readily apparent to local residents.

September continued the year-long trend of wet weather with 4.06 inches of rain, according to NIU Weather Service Director Lisa Hull. Field said the year-to-date precipitation in Rockford is 38.7 inches, nearly 10 inches above the normal.

October is a month of transition from relatively warm, sunny conditions in September to cloudy, frigid and even snowy weather in November. The normal mean temperature in Rockford drops by 25.2 degrees during those two months.

It should be no surprise, then, that the range in all-time low and high temperatures in October in DeKalb is between 7 and 93 degrees. This range is similar to London’s all-time low and high temperatures for its entire year, which are 9 to 99 degrees.

To make matters worse, according to Field, the 30 and 90-day outlooks both call for below normal temperatures in Northern Illinois. In fact, the period from October through December is expected to be much colder, wetter and probably snowier than normal. Precipitation is expected to be near normal in October, but a continuation of high rainfall this autumn would make 1993 one of the five wettest years on record.

The normal high and low temperatures for October in Rockford are 62.3 and 40.6 degrees, Field said. Normal precipitation is 2.88 inches.

According to NIU weather records, the warmest October was 1971, when the mean temperature was 59 degrees. The coldest was 1988, with a 45 degree mean. Precipitation has varied from less than one inch in 1963 to more than one foot in 1987.

Field said the early freeze which occurred on Sept. 30 was earlier than normal but not unprecedented. The average first frost in Rockford occurs on Oct. 9, but in 1975 frost occurred on Sept. 13.

NIU meteorologist Allen Staver said cool, wet summers are no indication of the kind of winter to follow. U.S. Climatic Data Center records indicate the dismal summer of 1950 was followed by a winter during which record lows for entire states were set.

Many of the Feb. 2, 1951 record lows still stand, including the all-time low of minus 35 degrees for Indiana, which occurred in Greensburg according to the 1993 World Almanac. Last winter, which followed the coolest and wettest summer since 1950, was quite mild.

Concerns about severe winter weather also were raised after the hot, dry summers of 1988 and 1991, both followed by mild winters. According to U.S. Climatalogical Data records, the blazing summers of 1934 and 1936 also were followed by very mild winters with little snow, but the hot, dry summer of 1983 was followed by a harsh winter.

Staver mentioned the last several winters have been quite mild, and climatic data supports this. The last severe winter in DeKalb occurred in 1985-86.

If the National Weather Service (NWS) outlook holds true for November and December, NIU could be in for a rude awakening from nearly a decade of tranquil winters. The NWS, however, had predicted cold temperatures last winter, and local temperatures remained above zero until mid-February. In any event, 1993 will be remembered more than anything else for its persistent rainfall.