Very dry May caps off meteorological spring in the Stateline

Meteorologist & Multimedia Journalist

ROCKFORD — Spring came to a warm and dry end earlier this week, capping off a season of big temperature swings and beginning a stretch of near-drought conditions which may stick around for weeks to come.

Overall, meteorological spring in the Rockford area was roughly around average in terms of temperature, but well below average in terms of precipitation, owing to a big rainfall deficit in May.

Here's a breakdown, month-by-month, of meteorological spring in the Rockford area.

March saw slightly cooler temperatures, with an average temperature of 36.7°, which is 0.6° below the 30-year average from 1991-2020.

The Chicago-Rockford International Airport recorded 3.3 inches of precipitation over the month, which is nearly an inch above average. The wetter March mostly comes from a snowier month, in which we saw 14.1 inches of snow, more than nine inches more than normal.

When the snow did fall, however, it did not last for long, as there were only three days of the entire month with a snowpack of at least an inch.

March 2023 will also hold historical significance to the Stateline, with the tornado outbreak on March 31, which also affected much of the United States. The outbreak, which spread into April 1, generated at least 145 tornadoes in 16 states, the third-largest tornado outbreak in recorded history. Only the 2011 Super Outbreak (359) and the 1974 Super Outbreak (148) seeing more.

17 of those tornadoes touched down in our northern Illinois and southern Wisconsin area, including the long-tracked EF-1 tornado which struck downtown Belvidere, causing the roof of the historic Apollo Theatre to collapse during a concert, killing one and injuring dozens more.

April was a month of big temperature swings, which is evident in the average high and low temperatures throughout the month.

The average high temperatures in Rockford was 62.2°, which is 2.5° above average, but the average low temperature was 36.2°, 2.3° below average. This balance led to an average temperature of 49.2°, which was only 0.1° above average.

The snow managed to stick around into the month of April, though nothing more than we usually see. 0.9 inches of snow fell in Rockford in April, which is exactly the average value for the entire month.

Despite the average snowfall, we did not see the average precipitation numbers in total. Rockford ran a precipitation deficit of about one inch in April, getting only 2.7 inches of liquid precipitation.

This would foretell a drier end to the Spring season, ushering in concerns of a developing drought.

The average temperature throughout the month of May was 61.5°, which is 1.1° above normal. What that number does not tell you, however, is that there was a bigger difference between high and low temperatures than normal.

The average low temperature in Rockford last month was 47.9°, 1.6° below normal. The days, however, were much warmer, with high temperatures in May averaging at 75.2°, which is 4° above normal.

We capped off the month on a rather hot note, with the hottest temperature recorded in the entire month set on May 31, when the mercury reached 89°.

Illinois Drought Monitor, data valid as of May 30, 2023

While the weather was rather warm this May, especially in the last week of the month, it was also remarkably dry across the Stateline, aiding in the expansion of drought conditions across the Midwest heading into the summer.

The Chicago-Rockford International Airport recorded two inches of rain over the entire month, which is only about half of the average amount for May. This proves quite problematic for farmers, trying to get their crops planted and able to receive enough water to begin growing.

According to forecasts from the Climate Prediction Center, the stretch of warmer and drier conditions is expected to last for much of the next month or so. Outlooks for the month of June show higher chances of both above average temperatures and less precipitation.

As for the rest of the season, the CPC says better news may be on the horizon.

Looking at the rest of the summer, outlooks from the CPC show equal chances of temperatures near averages over the whole season. Rockford's summer average high temperature is 82° and average low temperature is 60°.

In what may be even better news, long-range outlooks indicate rainfall levels potentially near or above average for the season, which would be beneficial for the growing season, in the hopes of offsetting the dry end to spring.

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Meteorologist & Multimedia Journalist