A Dry and Warm Late Autumn of 1999

The autumn of 1999 brought record warm temperatures and unusually dry conditions to much of Minnesota. Some interesting artifacts of this warmth and dryness can be seen with a look at Twin Cities temperature and precipitation statistics.

Days without below zero temperatures in the Twin Cities

Twin Cities temperatures stayed above zero from January 20, 1999 through December 19, 1999. This is a total of 334 days and ties 1998 for 3rd place in the modern record.

Longest intervals without below zero temperatures (1891-1998)
1) 2/13/54 to 1/15/55 337
2) 1/25/87 to 12/25/87 335
3) 1/20/99 to 12/19/99 334
3) 1/21/98 to 12/20/98 334
5) 1/31/15 to 12/26/15 330
5) 1/25/92 to 12/20/92 330
7) 1/15/31 to 12/6/31 326
8) 2/11/11 to 12/26/11 319
9) 1/28/24 to 12/10/24 317
10) 2/22/18 to 12/31/19 313

Days with above-freezing maximum temperatures in the Twin Cities

The Twin Cities broke a record for the longest consecutive stretch of maximum temperatures above 32 degrees. The maximum temperature was above 32 degrees from March 10 until December 16, 1999. The average consecutive days of above freezing maximum temperatures is 229. The shortest span of days with above freezing maximum temperatures was 164 days from May 1 to Oct 11 1909.

  Year days Start Date End Date
1) 1999 282 1999 3 10 1999 12 16
2) 1994 263 1994 3 10 1994 11 27
3) 1977 259 1977 3  7 1977 11 20
4) 1946 258 1946 3  9 1946 11 21
5) 1981 258 1981 3  7 1981 11 19
6) 1918 256 1918 3 10 1918 11 2
7) 1929 255 1929 3 10 1929 11 19
8) 1987 254 1987 3 11 1987 11 19
9) 1931 254 1931 3 16 1931 11 24
10)1948 253 1948 3 13 1948 11 20
Another very long-standing Twin Cities temperature duration record was broken as well. December 16th, 1999 marks the latest date into the autumn with a continous stretch of maximum temperature reaching above 32 degrees. The old record, was December 8, 1830.

Days with minimum temperatures => 20 degrees in the Twin Cities

Still another record was set in the Twin Cites in 1999 when the minimum temperature did not drop below 20 degrees until December 15th. This easily bested the old record of December 3rd set back in 1899.

Lack of snowfall in the Twin Cities

It was also unusually snow-free this late autumn across Minnesota. The Twin Cities didn't see the first 1 inch of snow cover until December 20. The dates without snow cover were March 17, 1999 through December 19, 1999, the second longest stretch on record. The top five longest stretches without a one inch snow depth are listed below. While the autumn of 1999 lacked snow, there are other years that saw even later first 1-inch snowfalls. 1999 tied 1939 for 8th latest 1 inch snowfall, and tied with 1914 for the latest 1-inch snow depth.

Longest stretch of days without snow cover (<1 inch)

1) March 16, 1918 December 26, 1918 286 days
2) March 17, 1999 December 19, 1999 279 days
3) March 19, 1998 December 20, 1998 277 days
4) March 16, 1942 December 14, 1942 274 days
5) March 27, 1960 December 23, 1960 271 days

Latest 1 inch snowfall (season) (From 1891-1997)

1) Jan 9, 1945 (44-45)
2) Jan 6, 1981 (80-81)
3) Jan 1, 1914 (13-14)
4) Dec 30, 1918 (18-19)
5) Dec 26, 1904 (04-05)
6) Dec 21, 1920 (20-21)
7) Dec 20, 1998 (98-99)
8) Dec 19, 1999 (99-00)
8) Dec 19, 1939 (39-40)
10) Dec 16, 1908 (08-09)

Latest 1 inch snow depth (season)* (From 1896-1997)

1) Jan 1, 1914 (13-14)
2) Dec 27, 1918 (18-19)
3) Dec 26, 1904 (04-05)
4) Dec 24, 1960 (60-61)
5) Dec 21, 1920 (20-21)
5) Dec 21, 1998 (98-99)
7) Dec 20, 1914 (14-16)
7) Dec 20, 1999 (99-00)
9) Dec 19, 1939 (39-40)
10) Dec 16, 1908 (08-09)
*observation time varies over the years from 8pm to 6:30 pm through 1949, to 6:30 am for years after 1949.

 

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URL: http://climate.umn.edu/doc/journal/autumn1999.htm
Last modified: December 20, 1999