July 16: ORD

Today is July 16th. It's the 197th day of the year. 168 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 63. I've calculated the 32-year averages at 86 and 65.

On the hot side, in 1988 the high was 99 with a low of 70. Five years ago, in 2006, the high was 94 with a low of 74. In 1995 the high was 93 with a low of 74. Our warmest low was 75 in 1982. The record high of 100 was set way back in 1887. Another high of 94 occurred in 1997. There were two other highs of 93 degrees (in 1986 and 2005). The record warmest low of 80 occurred way back in 1878. 29 of the past 32 highs (91%) were in the: 80s (16) and 90s (13). For 18 straight years, from 1993 through 2010, highs were in the 80s and 90s. Three highs were in the cool 70s, most recently 75 in 1992. Through 2010, this is the average third 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 1967 the high was 79 with a cold low of 49, a 30 degree spread. That low of 49 equals the record low of 49. In 1962 the high was a cool 72 degrees.

More recently, there were no small spreads of up to seven degrees or large spreads of at least 30 degrees.

On the cool side, in 1979 the high was 74 with a low of 55. In 1987 the high was 80 with a low of 52, our coolest low. The record low of 49 was set in 1945. Other cool highs were in the 70s: 75 in 1992 and 76 in 1985. The record coolest high of 62 occurred back in 1912. 26 of the last 32 lows (81%) were in the: 60s (16) and 70s (10). Six lows were in the cool 50s, most recently 59 in 2003.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:58 and sunrise is at 5:31. Sunset is at 20:27 and twilight ends at 21:01. There's a total of 14 hours, 56 minutes of daylight today and 16 hours, 3 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 4:58 and sunrise is at 5:32. The moon is waning gibbous, having passed the full Buck or Thunder moon early yesterday at 1:40. Illumination was 99% at midnight, will be 98% at noon and 96% at midnight tonight. Moonset is at 7:01 this morning. Moonrise is at 21:09 tonight. Moonset is at 8:06 tomorrow morning. Moonlight time is 9 hours, 52 minutes which is 35 minutes longer than yesterday.

Summer began June 4 and runs for 110 days through September 21. High temperatures in this period are usually in the 70s and 80s. Highs in the 60s, 90s and 100s occur infrequently. Parent's Day is in eight days.