June 25: ORD

Today is June 25th. It's the 176th day of the year. 189 days remain. It's week 26 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 85 and 60.

On the hot side, in 1988 the high was the record high of 103 with a low of 66, a 37 degree spread. That high of 103 is the second hottest high ever at O'Hare. Two years ago, in 2009, the high was 94 with a low of 75. In 1998 the high was 95 with a low of 70. Another hot high was 94 in 1983. The other 90s highs were 92 in 2003, 91 in 1989 and 91 in 2005. Other warm lows were 73 in 2002 and 72 in 2003. The record warmest low of 76 occurred way back in 1890. 19 of the past 32 highs (59%) were in the 80s. Seven highs (22%) were in the warm: 90s (6) and 100s (1). Six highs (19%) were in the cool 70s.

In looking back through the years to the first June at O'Hare in 1959, the following instances were notable: In 1978 the high was 75 with a low of 68, a seven degree spread. In 1974 the high was 70 with a low of 49, a cool day. In 1973 the high was 84 with a low of 50, a 34 degree spread. In 1970 the high was a cool 69 degrees. In 1969 the high was a hot 96 with a low of 60, a 36 degree spread. In 1965 the high was 73 with a cold low of 45, a cool day. In 1963 the high was 90 with a low of 53, a 37 degree spread.

More recently, the spreads were all large: 36 degrees in 1979 (80/44), 35 degrees in 1989 (91/56), 33 degrees in 1982 (83/50), 33 degrees in 1985 (84/51), 33 degrees in 1992 (80/47) and 31 degrees in 1983 (94/63).

On the cool side, in 1986 the high was 77 with the record low of 41, a 36 degree spread. In 2004 the high was 72 (our coolest high of the last 32 years) with a low of 49 (our most recent 40s low). Other cool lows were 44 in 1979 and 47 in 1992. The record coolest high of 56 occurred back in 1928. 23 of the last 32 lows (72%) were in the: 50s (9) and 60s (14). Four lows (12%) were in the cool 40s and five lows (16%) were in the warm 70s. Our most recent 50s low was 58 in 2001.

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 no minutes of daylight from yesterday. Tomorrow twilight begins at 4:44 and sunrise is at 5:18. The moon reached last quarter two days ago at 6:48 and is waning crescent. Illumination was 34% at midnight, will be 29% at noon and 25% at midnight tonight. Moonrise is at 1:10 this morning. Moonset is at 15:20 this afternoon. Moonrise is at 1:39 tomorrow morning. Moonlight time is 14 hours, 10 minutes which is 34 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 nine days.