June 24: ORD

Today is June 24th. It's the 175th day of the year. 190 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 60. I've calculated the 32-year averages at 83 and 60.

On the hot side, in 2005 the high was 96 with a low of 76. Two years ago, in 2009, the high was 94 with a low of 75. In 1997 the high was 93 with a low of 75. A year later, in 1998, the high was 94 with a low of 71. Another hot high was 94 in 1995. The record high of 97 was last set in 1953, having originally occurred in 1937. The record warmest low of 77 occurred back in 1923. 29 of the past 32 highs (91%) were in the: 70s (8), 80s (11) and 90s (10). Three highs were in the cool 60s.

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 67 degrees. In 1969 the high was a cool 66 with a low of 59, a seven degree spread. In 1967 the high was a cool 68 degrees. In 1965 the low was a cold 48 degrees. In 1963 the high was 88 with a cold low of 48, a 40 degree spread. In 1961 the low was a cold 47 degrees. In 1959 the high was 90 with a low of 60, a 30 degree spread.

More recently, the spreads were all large: 31 degrees in 1987 (91/60), 31 degrees in 1995 (94/63), 31 degrees in 2001 (81/50), 31 degrees in 2006 (82/51) and 30 degrees in 1983 (91/61).

On the cool side, in 1986 the high was 61 with the record low of 46. In 1979 the high was 69 with a low of 49. Another cool high was 69 in 1994, our most recent 60s high. The record coolest high of 59 occurred back in 1917. 25 of the last 32 lows (78%) were in the: 50s (12) and 60s (13). Three lows were in the cold 40s and four lows were in the warm 70s. Our most recent 40s low was 49 in 1990.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:43 and sunrise is at 5:18. Sunset is at 20:34 and twilight ends at 21:08. There's a total of 15 hours, 16 minutes of daylight today and 16 hours, 25 minutes between twilights. We lost a minute of daylight from yesterday. Tomorrow twilight begins at 4:43 and sunrise is at 5:18. The moon reached last quarter yesterday at 6:48 and is waning crescent. Illumination was 43% at midnight, will be 38% at noon and 34% at midnight tonight. Moonrise is at 0:44 this morning. Moonset is at 14:20 this afternoon. Moonrise is at 1:10 tomorrow morning. Moonlight time is 13 hours, 36 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. Independence Day is in ten days.