July 22: ORD

Today is July 22nd. It's the 203rd day of the year. 162 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 32-year averages at 83 and 64.

On the hot side, in 1991 the high was the record high of 101 with a low of 74. The record high of 101 originally occurred in 1934. In 1983 the high was our former record high of 100 with a low of 73. Other hot highs were 95 in 2001 and 93 in 1984. Another warm low was 76 in 2002. The record warmest low of 80 occurred in 1972. 23 of the past 32 highs (72%) were in the: 70s (13) and 80s (10). Nine highs (28%) were in the hot: 90s (7) and 100s (2).

Yesterday's high of 99 at 18:16 and low of 75 at 0:58 (today) tied 2002 (96/78) as the hottest July 21st. The second hottest is 1998 (94/76) and third is 1983 (96/72). Rockford and West Chicago had highs of 97. Midway hit 101. The lakefront in Chicago and Kankakee hit 100. Joliet and Romeoville (at the National Weather Service) hit 99.

In looking back through the years to the first July at O'Hare in 1959, the following instances were notable: In 1974 the high was a cool 71 degrees. In 1973 the high was 79 with a low of 72, a seven degree spread. In 1972 the high was 93 with a warm low of 79, a hot day. 1972 had the same temperatures two days in a row (on the 21st & 22nd) and is the year of the record warmest low (80 at Midway). In 1966 the high was 84 with a cool low of 48, a 36 degree spread.

More recently, there was a large spread of 30 degrees in 1984 (93/63) and a small spread of four degrees in 1997 (71/67).

On the cool side, in 2000 the high was 72 with a low of 53. In 1981 the high was 74 with a low of 55. In 1992 the high was 71 with a low of 58. Another cool high was 71 in 1997. Another cool low was 53 in 1996. The record low of 49 and record coolest high of 68 were set on the same cool day back in 1947. 19 of the last 32 lows (59%) were in the 60s. Seven lows (22%) were in the cool 50s. Six lows (19%) were in the warm 70s. Our most recent 70s low was 76 in 2002.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:03 and sunrise is at 5:36. Sunset is at 20:23 and twilight ends at 20:56. There's a total of 14 hours, 47 minutes of daylight today and 15 hours, 53 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 5:04 and sunrise is at 5:37. The moon is waning gibbous, heading for last quarter tomorrow at 0:02. Illumination was 59% at midnight, will be 54% at noon and 50% at midnight tonight. Moonset is at 13:08 this afternoon. Moonrise is at 23:39 tonight. Moonset is at 14:08 tomorrow afternoon. Moonlight time is 13 hours, 29 minutes which is 33 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 two days.