May 13: ORD

Today is May 13th. It's the 133rd day of the year. 232 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 69 and the normal low is 46. I've calculated the 32-year averages at 68 and 47.

On the warm side, in 1991 the high was the record high of 89 which tied the original record high set in 1956. The low in 1991 was 64. In 2004 the high was 78 with a low of 65. The only other 80s high was 86 in 1982. The only other 60s low was 61 in 1983. The record warmest low of 72 occurred in 1956. So as you can see, 1956 was the warmest day, having a high of 89 and low of 72. 23 of the last 32 highs (72%) were in the: 60s (10) and 70s (13). On the warmer side, two highs were in the 40s. On the cold side, seven highs were in the 50s.

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 a warm 82 with a low of 57, a warm day. In 1975 the high was 73 with a low of 37, a 36 degree spread. In 1973 the high was a cool 57 degrees. In 1971 the high was 73 with a low of 37, a 36 degree spread. In 1968 the high was 77 with a low of 43, a 34 degree spread. In 1966 the high was a cold 44 with a low of 40, a four degree spread and cold day. In 1964 the high was a cool 51 with a low of 40, a cool day. In 1962 the high was a warm 84 with a low of 57, a warm day. In 1961 the high was 86 with a low of 61, a hot day.

More recently, we had a small spread of five degrees in 1999 (53/48). The large spreads were: 38 degrees in 1987 (78/40), 35 degrees in 1982 (86/51), 33 degrees three years ago (in 2008)(73/40), 32 degrees in 1984 (72/40) and 31 degrees in 2001 (68/37).

On the cool side, in 1996 the high was 56 with the record low of 34. The record low of 34 also occurred way back in 1888. A decade later, in 2006, the high was 50 with a low of 42. The other 30s lows were 37 in 2001 and 39 in 1997. The other cool highs were 53 in 1999, 55 in 1997, 56 in 2002 and 57 in 1993. The record coldest high of 43 was set in 1953. 22 of the last 32 lows (69%) were in the 40s. Three lows were in the cold 30s. Seven lows were in the warmer: 50s (4) and 60s (3).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight is at 5:03 and sunrise is at 5:35. Sunset is at 20:05 and twilight ends at 20:37. There's a total of 14 hours, 30 minutes of daylight today and 15 hours, 34 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 5:02 and sunrise is at 5:34. The moon is waxing gibbous. Illumination was 76% at midnight, will be 81% at noon and 86% at midnight tonight. Moonset is at 2:53 this morning. Moonrise is at 15:54 this afternoon. Moonset is at 3:23 tomorrow morning. Moonlight time is 10 hours, 59 minutes which is 46 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. Armed Forces Day is in eight days. -Bernie-