June 29: ORD

Today is June 29th. It's the 180th day of the year. 185 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 82 and the normal low is 61. I've calculated the 32-year averages at 81 and 61.

On the hot side, in 1991 the high was 96 with a low of 71. A decade before, in 1981, the high was 96 with a low of 70. In 1996 the high was 92 with a low of 73. The only other 90s high was 90 in 2005. The only other 70s low was 73 in 2005. The record high of 97 was set in 1954. The record warmest low of 80 occurred in 1931. 27 of the past 32 highs (84%) were in the: 70s (14) and 80s (13). Four highs were in the hot 90s. One high was in the cool 60s. The lone 60s high was 68. It occurred on one of the two coolest days of the past 32 years in 1984.

In looking back through the years to the first June at O'Hare in 1959, the following instances were notable: In 1971 the high was 95 with a low of 73, a hot day. In 1966 the high was 89 with a low of 57, a 32 degree spread.

More recently, there was a large spread of 34 degrees in 1992 (88/54).

On the cool side, in 1989 the high was 73 with the record low (and only 40s low) of 48. Five years before, in 1984, the high was 68 with a low of 53. The other cool highs were 70 in 1982, 70 in 1988 and 70 in 2007. The record coolest high of 59 was set way back in 1902. 27 of the last 32 lows (84%) were in the: 50s (13) and 60s (14). One low was in the cold 40s. 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 4:45 and sunrise is at 5:20. Sunset is at 20:34 and twilight ends at 21:08. There's a total of 15 hours, 14 minutes of daylight today and 16 hours, 23 minutes between twilights. We lost a minute of daylight from yesterday. Tomorrow twilight begins at 4:46 and sunrise is at 5:20. The moon is waning crescent. Illumination was 5% at midnight, will be 3% at noon and 1% at midnight tonight. Moonrise is at 3:39 this morning. Moonset is at 19:16 tonight. Moonrise is at 4:35 tomorrow morning. Moonlight time is 15 hours, 37 minutes which is 8 minutes longer than yesterday. Moonlight time is at it's peak for the next several days, just when we can't see it!

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 five days.