May 2: ORD

Today is May 2nd. It's the 122nd day of the year. 243 days remain. It's week 18 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 66 and the normal low is 42. I've calculated the 31-year averages at 64 and 43.

On the warm side, in 2001 the high was 81 with the record warmest low of 65. The warmer 70s highs were 76 in 1982, 76 in 1992, 75 in 1980, 75 in 1988 and 74 two years ago. The record high of 91 occurred in 1959. 29 of the last 31 highs were: 50s (11), 60s (8) and 70s (10). On the warmer side, one high was in the 80s. On the cooler side, one high was in the 40s.

In looking back through the years to the first May at O'Hare in 1959, the following instances were notable: in 1978 the high was 55 with a low of 29, a cold day. In 1976 the high was a cool 54. In 1971 the high was a cold 50 with a low of 35, a cold day. In 1970 the high was a cold 46 with a low of 39, another cold day. In 1969 the high was 84 with a low of 55, a warm day. In 1968 the high was 85 with a low of 35, a huge 50 degree spread. In 1967 the high was a cold 49 with a low of 36, another cold one. In 1966 the high was 58 with a cold low of 28, a 30 degree spread and just a degree above the record low. In 1965 the high was a warm 84 with a low of 49, a 35 degree spread and warm day. In 1959 the high was 89 with a low of 61, a hot day. And yes, 1959 (see above) was the year of the record high.

More recently, we had no small spreads. The large spreads were 38 degrees in 1982 (76/38), 36 degrees in 1988 (75/39), 31 degrees in 1999 (73/42), 31 degrees in 1980 (75/44) and 30 degrees in 1990 (68/38).

On the cool side, in 2005 the high was 44 with a low of 35. That high of 44 was the only high below 50 at O'Hare since 1970. The year earlier, 2004, the high was 51 with a low of 32. Other cool highs were 50 in 1989, 53 in 2002, 53 in 2003 and 54 in 1997. The record low of 27 was set way back in 1875. The record coldest high of 37 was set back in 1940. 25 of the last 31 lows were: 30s (9) and 40s (16). Six lows were in the warmer: 50s (5) and 60s (1).

Today is a major day in Chicago's snow history. 1940 holds the record for the latest two inches or more. According to the record, 2.2 inches of snow fell in Chicago between the 1st, 2nd and 3rd. There is no indication of how much fell on what day. Tom Skilling says that 3.7 inches fell at the University of Chicago on the 1st and 2nd. Rockford had a total of 2 inches of snow (1.5 on the 1st and 0.5 on the 2nd).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:17 and sunrise was at 5:47. Sunset is at 19:54 and twilight ends at 20:25. There's a total of 14 hours, 7 minutes of daylight today and 15 hours, 8 minutes between twilights. Tomorrow twilight begins at 5:15 and sunrise is at 5:46. The moon is waning gibbous. Illumination was 85% at midnight, will be 81% at noon and 77% at midnight tonight. Moonset was at 8:42. Moonrise is at 26 minutes past midnight tomorrow. Moonset is at 9:43 tomorrow. Moonlight time is 8 hours, 42 minutes which is 40 minutes longer than yesterday.

National Teacher Day is in three days. Mother's Day is in a week. - Bernie -