July 18: ORD

Today is July 18th. It's the 199th day of the year. 166 days remain. It's week 29 of the year.

Unless noted, the following data is based upon observations collected by the National Weather Service, Chicago, at O'Hare International Airport (ORD) between November 1978 and last year. ORD has been the official site of record for Chicago since Thursday, January 17, 1980.

According to the National Climatic Data Center (NCDC), the normal high is 84 and the normal low is 64. I've calculated the 31-year averages at 85 and 66.

On the hot side, there were no days of a mean of at least 11.5 degrees above normal. 1986 was the hottest day with a high of 93 and low of 75. 1991 (96/70) and 2005 (91/75) are runner-ups. That high of 96 in 1991 was the hottest O'Hare has seen, but the record high of 100 was set in 1946. The warmest lows were 75 in both 1986 and 2005. The record warmest low of 78 occurred in 1942. 14 of the last 31 highs were 80s. Nine highs were in the warmer 90s and eight highs were in the cooler 70s. Through 2010, this is the average fourth hottest day of the year.

In looking back through the years to the first July at O'Hare in 1959, the following instances were notable: In 1966 the high was 95. While that high of 95 is certainly hot, both the day (95/67) and the high fall just short of being exceptional.

More recently, there was a large spread of 37 degrees in 1979 (82/45).

On the cool side, there were no days of a mean of at least 11.5 degrees below normal. 1979 was the coolest day, as the high was 82 with the coolest low of 45 degrees, a low cooler than the record. The record low of 53 was set in 1979 at Midway. The coolest highs were 71 in 2000 and 72 last year. The record coolest high of 62 occurred back in 1924. 16 of the last 31 lows were 60s. Six lows were in the cooler: 40s (1) and 50s (5). Nine lows were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:00 and sunrise was at 5:33. Sunset is at 20:26 and twilight ends at 20:59. There's a total of 14 hours, 53 minutes of daylight today and 15 hours, 59 minutes between twilights. Tomorrow twilight begins at 5:01 and sunrise is at 5:34. The moon reached first quarter today at 5:11. Illumination was 48% at midnight, will be 54% at noon and 59% at midnight tonight. Moonrise is at 13:57 this afternoon. Moonset is at 5 minutes past midnight and moonrise is at 15:08 tomorrow. Moonlight time is 10 hours, 3 minutes which is 46 minutes shorter than yesterday.

Parent's Day is in seven days. - Bernie -