May 8: ORD

Today is May 8th. It's the 128th day of the year. 237 days remain. It's week 19 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 67 and the normal low is 45. I've calculated the 32-year averages at 70 and 48.

On the warm side, in 1979 the high was a near-record 90 degrees with an above-record low of 68. The record warmest low is 67, set in 1963 at Midway. The record high of 91 was set in 1963. 1963 was a scathingly hot day as it's mean was 22 and a half degrees above normal. The 68 degree low at O'Hare in 1979 is not the record for Chicago since O'Hare was not the official station of record in 1979; Midway was. In 2000 the high was 85 with a near-record low of 66. In 1993 the high was 85 with a low of 59. In 1990 the high was 81 with a low of 60. In 1988 the high was 85 with a low of 52, a 33 degree spread. To complete the listing of days of 11.5 or more degrees above normal mean, in 2007 the high was 82 with a low of 54. Other 80s highs were 84 in 2004 and 85 in 2005. The other mid 70s highs were 76 in 2001 and 77 two years ago in 2009. There were three other lows in the 50s: 53 two years ago in 2009, 52 in 1998 and 51 in 1997. 25 of the last 32 highs (78%) were in the: 60s (9), 70s (9) and 80s (7). Our most recent 60s highs were 65 in 2002 and 61 in 2003. On the warmer side, one high (90 in 1979) was in the 90s. On the cool side, six highs were in the: 40s (1) and 50s (5). Two of the 50s highs occurred in the last three years.

In looking back through the years to the first May at O'Hare in 1959, the following instances were notable: In 1977 the high was 70 with a low of 34, a 36 degree spread. In 1976 the high was 64 with a low of 34, a 30 degree spread. In 1974 the high was a cold 45 with a low of 42, a three degree spread and cold day. In 1972 the high was a cold 44 with a low of 39, a five degree spread and cold day. In 1971 the high was 74 with a low of 41, a 33 degree spread. In 1970 the high was 86 with a low of 63, a hot day. In 1968 the high was 78 with a warm low of 57, a warm day. In 1966 the high was a cold 45 with a low of 35, a cold day. In 1965 the high was 83 with a low of 61, a warm day. In 1964 the high was 79 with a low of 61, a warm day. In 1963 the high was 90 with a low of 67, a hot day. 1963 was also the year of the record high and record warmest low. In 1960 the high was a cold 41 with a low of 35, a six degree spread and cold day. 1960 was also the year of the record coldest high.

More recently, we had large spreads of 42 degrees in 2005 (85/43), 35 degrees in 2004 (84/49), 32 degrees in 1992 (72/40) and 31 degrees in 1981 (63/32).

On the cool side, in 1983 the high was 48 with the record low of 29. A year later, in 1984, the high was 51 with a low of 38. Another cold low was 32 in 1981. The only other 30s low was 39 in 1994. Other cool highs were 50 last year (in 2010) and 54 in 1980. The record coolest high of 42 was set in 1960. 19 of the last 32 lows (59%) were in the 40s. Four lows (13%) were in the cold: 20s (1) and 30s (3). Nine lows (28%) were in the warm: 50s (6) and 60s (3).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight is at 5:09 and sunrise is at 5:40. Sunset is at 20:00 and twilight ends at 20:31. There's a total of 14 hours, 20 minutes of daylight today and 15 hours, 22 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 5:08 and sunrise is at 5:39. The moon is waxing crescent and will reach first quarter in two days at 15:33. Illumination was 23% at midnight, will be 28% at noon and 33% at midnight tonight. Moonset is at 0:12 this morning. Moonrise is at 9:58 this morning. Moonset is at 0:51 tomorrow morning. Moonlight time is 14 hours, 14 minutes which is 53 minutes shorter than yesterday.

The warm part of Spring (Warm Spring) began on April 13. Warm Spring runs for 52 days, through June 3. High temperatures in this period are usually in the 50s, 60s and 70s. Warmer 80s and 90s occur infrequently. Mother's Day is today. Armed Forces Day is in 13 days. -Bernie-