June 6: ORD

Today is June 6th. It's the 157th day of the year. 208 days remain. It's week 23 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 77 and the normal low is 55. I've calculated the 32-year averages at 78 and 55.

On the hot side, in 1999 the high was 91 (our most recent 90s high) with a low of 69. Three years ago, in 2008, the high was 87 with a low of 73. In 1984 the high was 89 with a low of 66. In 1988 the high was 91 with a low of 64. In 2005 the high was 89 with a low of 66. Other hot highs include 90 in both 1979 and 1994. The record high of 97 was set in 1971 and the record warmest low of 77 occurred back in 1925. 21 of the past 32 highs (66%) were in the: 70s (9) and 80s (12). Four highs (12%) were in the hot 90s. Seven highs (22%) 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 1976 the high was 84 with a low of 53, a 31 degree spread. In 1971 the high was 92 with a low of 68, the year of the record high and a hot day. 1971 had the same high and low (92 & 68) for yesterday (the 5th) and today. In 1968 the high was a hot 90 with a low of 66, a hot day. In 1963 the high was 90 with a low of 68, a hot day.

More recently, there was a large spread of 39 degrees in 1979 (90/51), 33 degrees in 1982 (73/40) and 33 degrees in 1992 (83/50).

On the cool side, in 1998 the high was 64 with a low of 43. In 1985 the high was 69 with the record (and only 30s) low of 39, a 30 degree spread. Other cool highs were 62 in 2001, 63 two years ago (in 2009) and 65 in 1986. Another cool low was 40 in 1982. The record coolest high of 50 occurred way back in 1894. 16 of the last 32 lows (50%) were in the 50s. Seven lows (22%) were in the cold: 30s (1) and 40s (6). Nine lows (28%) were in the warm: 60s (8) and 70s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:44 and sunrise is at 5:18. Sunset is at 20:27 and twilight ends at 21:01. There's a total of 15 hours, 9 minutes of daylight today and 16 hours, 17 minutes between twilights. We gained a minute of daylight from yesterday. Tomorrow twilight begins at 4:43 and sunrise is at 5:17. The moon is waxing crescent. Illumination was 20% at midnight, will be 25% at noon and 30% at midnight tonight. Moonrise is at 10:07 this morning. Moonset is at 23:59 tonight. Moonrise is at 11:18 tomorrow morning. Moonlight time is 13 hours, 52 minutes which is 37 minutes shorter 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. Flag Day is in eight days.