September 1999 Saint Cloud Weather Summary

DATE: 1 October 1999

SUBJECT: How Dare This September Be So....Normal

Saint Cloud September 1999 weather summary

If this September felt cold to you, then you are in need of a reality check. The September temperatures from the St. Cloud Regional Airport show a nearly perfectly normal month in both high and low temperatureaverages. The shock comes after a September in 1997 which was 3 degrees above normal and a September of 1998 which was the warmest September in 50 years.

The incredibly normal weather pattern was produced by an alternation between warm air masses from the Southern Plains and the first incursions of Canadian Polar air masses from the Prairie Provinces. The last of thereally hot and humid weather was pushed out after September 3, allowing a more normal weather pattern. However, the cooler air was winning late in the month and the first weekend of October will be off to a very chilly start.

No temperature records were set and the first frost came along close to the normal time. The temperature dropped below 32 degrees for the first time on September 21, bringing an end to the growing season for delicate plants. Thanks to an early last frost on April 21, the growing season for frost was 149 days, 7 days longer than normal. September 29 hit 28 degrees, bringing an end to the growing season for hardier plants 10 days earlier than normal. Still, the early end to cold temperatures in April allowed a growing season of only 4 days less than normal for those plants hardy enough to survive down to a temperature of 28 degrees.

Rainfall in St. Cloud was about a half an inch below normal. This continues the '90's trend of dry Septembers. Eight of the 10 '90's Septembers have had less than normal rainfall and 5 of these years have had less than 2 inches of rain. However, this could be seen as counteracting the '80's trend in which 5 of the 10 years had September rainfall between 4.3 and 9.4 inches.

On the other hand, St. Cloud joined most of the rest of the state in being well above normal in growing season rainfall (April 1-Sept. 30).The total 6-month rainfall was 22.45 inches, almost two inches above thenormal of 20.61 inches.

SUMMARY FOR SEPTEMBER 1999             SEP 1999         NORMAL

TEMPERATURE

Average high temperature (F)            69.1             69.1

Average low temperature (F)             45.0             45.4

Average temperature (F)                 57.1             57.3

Warmest high for this month (F)         89 on the 3rd

Coolest high for this month (F)         54 on the 20th

Mildest low for this month (F)          67 on the 2nd

Coldest low for this month (F)          28 on the 29th

PRECIPITATION (in)

September                               2.61              3.14

Greatest in 24 hours (Sept 1998)        .58 on the 4th

GROWING SEASON STATISTICS

Temperature cutoff        last day in spring   first day in fall  no of days

32 degrees                   

1999                          April 24            Sept 21             149

normal                        May 10              Sept 26             142

28 degrees

1999                          April 24            Sept 29             157

normal                        April 28            Oct  8              161