October 10: ORD

Today is October 10th. It's the 283rd day of the year. 82 days remain. It's week 41 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 65 and the normal low is 44. I've calculated the 31-year averages at 62 and 42.

On the warm side, there were no days of a mean of at least 11.5 degrees above normal. The warmest highs were in the upper 70s (79 in 1999 and 77 in 2003). The record high was 86 in 1962 (at Midway). The warm low was 56 in 1984. The record warmest low of 68 occurred way back in 1879. Over the last 31 years, 22 highs (71%) have been: 50s (8) and 60s (14). There were five highs in the warmer 70s and four highs in the cooler 40s, including last year's high of 48. Last year was the coolest October 10 of the last 31 years. The last 31 years have not produced a high of 80 or higher. That will likely change today as the predicted high is 85 in Crystal Lake and at least 84 at O'Hare. Today will rival 1961 (80 degrees), 1962 (87 degrees), 1963 (82 degrees) and 1973 (81 degrees) as O'Hare's warmest October 10th ever.

Yesterday's high of 86 at O'Hare at 4:36 PM tied the old record high for Chicago which was set in 1949 at Midway. Rockford hit 90 at 3:24 PM, shattering their old record of 84, set in 1920. Midway hit 87, breaking their own record (in 1949). The lows were 55 at O'Hare, 53 at Rockford and 56 at Midway. West Chicago hit 88 degrees after a low of 50. The National Weather Service in Romeoville reported a high of 88 after a low of 52. Aurora had a high of 89 after a low of 47. Others: DeKalb: 86/53, Joliet: 90/48 and Kankakee: 90/46. The spreads (difference between the high and low temperatures) were large because the air mass was very dry. Chicago's lakefront was a lot cooler, having attained a high of 78 after a low of 63.

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1978 the high was 62 with a low of 55, a seven degree spread. In 1974 the high was 70 with a low of 38, a 32 degree spread. In 1973 the high was 81 with a low of 65, a warm day. In 1967 the high was a cool 51 with a low of 36, a cool day. In 1964 the high was 48 with a low of 20 (cooler than the record low and year of the record low), a cold day. In 1963 the high was a warm 82 with a low of 50, a 32 degree spread. In 1962 the high was a hot 87 with a low of 43, a 44 degree spread. 1962 was the year of the record high (see above). In 1961 the high was 80 with a low of 60, a warm day. In 1960 the high was a warm 79 with a low of 47, a 32 degree spread.

More recently, there was a large spread of 30 degrees two years ago (72/42). There were small spreads of six degrees in 2006 (58/52) and seven degrees three years ago (54/47).

On the cool side, last year the high was 48 with a low of 31. In 1996 the high was 50 with a low of 31. In 1990 the high was 48 with a low of 34. In 1993 the high was 53 with a low of 30. In 1987 the high was 48 with a low of 37. In 1985 the high was 47 with a low of 39. The record low of 27 was set in 1964. The record coolest high of 39 occurred way back in 1906. 25 of the last 31 lows (81%) were: 30s (12) and 40s (13). Six lows were in the warmer 50s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:32 and sunrise is at 7:00. Sunset is at 18:20 and twilight ends at 18:48. There's a total of 11 hours, 20 minutes of daylight today and 12 hours, 16 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 6:33 and sunrise is at 7:01. The moon is waxing crescent. Illumination was 9% at midnight, will be 12% at noon and 16% at midnight tonight. Moonrise is at 10:38 this morning. Moonset is at 19:58 tonight. Moonrise is at 11:44 tomorrow morning. Moonlight time is 9 hours, 20 minutes which is 28 minutes shorter than yesterday.

Columbus Day is tomorrow and United Nation's Day is in 14 days. -Bernie-