June 23: ORD

Today is June 23rd. It's the 174th day of the year. 191 days remain. It's week 25 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 81 and the normal low is 59. I've calculated the 32-year averages at 82 and 60.

On the hot side, two years ago, in 2009, the high was 94 with a low of 71. In 1997 the high was 92 with a low of 72. Five years later, in 2002, the high was 92 with a low of 72 as well. The other 90s highs were 93 in 1983, 93 in 2005 and 91 in 1995. The record high of 97 was set back in 1930. The record warmest low of 79 occurred back in 1923. 24 of the past 32 highs (75%) were in the: 70s (10) and 80s (14). Six highs (19%) were in the hot 90s. Two highs were in the cool: 50s (1) and 60s (1).

In looking back through the years to the first June at O'Hare in 1959, the following instances were notable: In 1974 the high was a cool 63 with a low of 51, a cool day. In 1972 the high was 70 with a cold low of 44, a cool day. In 1969 the high was a cool 67 degrees. In 1968 the high was a hot 94 with a low of 58, a 36 degree spread. In 1963 the high was 84 with a cold low of 44, a 40 degree spread. The lows of 44 in 1963 and 1972 unofficially tied the record low.

More recently, there was one small spread of five degrees in 2007 (67/62). The other spreads were large: 33 degrees in 2005 (93/60), 31 degrees in 1983 (93/62) and 31 degrees in 1993 (87/56).

On the cool side, in 1979 the high was 59 with a low of 50. In 1982 the high was 75 with the record low of 44, a 31 degree spread. The record coolest high of 58 occurred at Midway in 1979. Another cool high was 67 in 2007. 27 of the last 32 lows (84%) were in the: 50s (14) and 60s (13). One low was in the cold 40s and four lows were in the warm 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:43 and sunrise is at 5:17. Sunset is at 20:34 and twilight ends at 21:08. There's a total of 15 hours, 17 minutes of daylight today and 16 hours, 25 minutes between twilights. We gained a minute of daylight from yesterday. Tomorrow twilight begins at 4:43 and sunrise is at 5:18. The moon reaches last quarter today at 6:48. Illumination was 52% at midnight, will be 48% at noon and 43% at midnight tonight. Moonrise is at 0:20 this morning. Moonset is at 13:21 this afternoon. Moonrise is at 0:44 tomorrow morning. Moonlight time is 13 hours, 1 minute which is 39 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. Independence Day is in 11 days.