Posted: 6:00 AM 8/1/13
Update: 5:03 PM 8/20/13
July 2013 started off feeling more like October. High temperatures for the first 4 days were in the 70s with scattered showers and thunderstorms every day. This was caused by an area of low pressure stuck in the Midwest while an area of high pressure brought record breaking temperatures to the southwest U.S.
Things became a bit drier for Friday the 5th and through the weekend, but temperatures started to warm up. On Monday, the 8th, highs were in the upper 80s and low 90s with Dewpoints in the 70s. This put heat index numbers in the upper 90s. However, the isolated rain chances returned on the 8th and the warm, muggy, and somewhat stormy pattern stuck around through Wednesday morning.
Wednesday got off to a very stormy start with heavy rain and a few trees down, mostly in Vermilion County. However, the cooler air that arrived behind the rain was quite a relief. Thursday and Friday were both much more pleasant with highs only around 80 and less humidity. Overnight lows were even into the 50s.
The next warm-up arrived for the weekend, but the weekend wasn't really too bad with middle 80s on Saturday and upper 80s on Sunday. However, by Monday we were seeing upper 80s and lower 90s with heat index values in the lower 100s in a few spots. Heat index numbers over 100 would become widespread by Tuesday and reach 105 by Wednesday and the same on Thursday and Friday.
The weekend was a bit cooler after a round of storms on Friday night and Saturday morning. Temperatures Saturday were in the middle 80s and Sunday struggled into the lower 80s. Sunday saw the return of storms in the evening that lasted through the overnight hours. Heavy rain was noted in many places, including over 3" in Savoy.
More storms returned to the area for Tuesday morning and a cool-down was put into place. Highs on Tuesday were in the lower 80s, but Wednesday morning was in the middle 50s! Highs on Wednesday were only in the middle 70s and we'd repeat the cool start on Thursday morning. We started to see some recovery from the cooler temperatures with a high near 80 on Thursday and Friday. However, Friday evening had some showers that brought the cooler air back in.
The last weekend in July felt more like the last weekend in September. High temperatures were only in the lower to middle 70s and the lows were in the 50s. Sunday morning we got very close to a few records. Monday had highs in the upper 70s to continue the cool streak. The last two days of July had scattered showers around that kept temperatures down and only in the 70s.
Illinois recorded the 19th coolest July on record with a statewide average temperature of 73.3 degrees. That's about 2.0 degrees below the 1981-2010 average. Precipitation amounts were on the low side, but very sporadic. The statewide average was 2.74", which is 1.31" below the 1981-2010 average, making this the 29th driest July on record.
After a record breaking start to the year, we're now on pace to have the 2nd wettest year on record. The statewide total precipitation average stands at 31.48", which is 7.61" above the 1981-2010 average.
The average temperature for July across the U.S. was 74.3 degrees F, just 0.8 above the 20th century average. This makes July 2013 the 30th warmest July on record. Precipitation finished as the 5th wettest on record, despite the Midwest being fairly dry. The nationally averaged total was 3.47", which is 0.71" above average. Check out this map for the climate events in the U.S. for July 2013.
So far this year, the U.S. has had an average temperature of 51.8 degrees F, just 0.5 degrees above the 20th century average. That puts us on pace to have the 42nd warmest year on record. Rainfall has an average of 19.14", which is 1.54" above average and puts us on pace to tie the 22nd wettest year on record.
July 2013 was the 6th warmest on record at 1.1 degrees F above the 20th century average. This continues a warm trend for the year that has 2013 on pace to be the 6th warmest on record, currently tied with 2003 at 1.06 degrees F above the 20h century average. Also, Arctic ice sheet reached its 5th smallest July extent in the 35 year period of records. At the same time, the Antarctic ice sheet reached its second largest July extent on record. Check out this map for the global climate stories of July 2013.