Weather

September 2015 Saint Cloud Weather Summary


September Warmth Rolls On

Corrected for First St. Cloud Frost on Sept. 30

4th (tie) Warmest September in St. Cloud Records; Warmest in 72 Years

September 2015 Saint Cloud Weather Summary

While this summer wasn't particularly warm, September hung on to a summer feel for much of the month. The result produced an September St. Cloud average temperature of 64.8°F. That tied 1933 for the 4th warmest September on record, and was 6.2°F warmer than average. 6 of the first 7 days of September had a high of 80 degrees or warmer with a near 90 degree temperature on September 4. More remarkable was the September 5 low of 72 degrees, the only low warmer than 70 degrees all year. That's also the first September low of 70 or high since 1973.

There were a few frosts in northern Minnesota during the last week of September with a hard freeze (28 degrees or colder) in far northern Minnesota. The St. Cloud Airport did finally hit 32 degrees on the last day of the month. This was later than about two-thirds of the falls in St. Cloud records with only 30% of falls having the first frost on October 1 or later. The late freeze has caused the turning of the leaves to be delayed, so Minnesota Department of Natural Resources fall colors chart shows color about a week or two later than average.

The last frost was on April 29, so there were 153 days with a temperature above freezing. Only 15% of growing seasons in St. Cloud were at least 153 days long.

There will be more opportunities for frost and perhaps a hard freeze through the weekend.

The rain continued its slower pace that began in August. St. Cloud Regional Airport only picked 2.24 inches of September rain, 1.22 inches less than average. However, there were 12 days with measurable rainfall. For the growing season (April 1- September 30) so far, St. Cloud is running 4.63 inches above average and, for the year, St. Cloud is 2.81 inches above average. Thus, this growing season so far ranks 24th in wetness and this year ranks 36th.

However, there was a lot more rain in north central and northeast Minnesota as well as the southern third of the state through the Twin Cities.

    September 2015 Statistics

Temperatures (°F)
September 2015
Normal
Average High Temperature (°F)
75.7
70.3
Average Low Temperature (°F)
53.8
46.8
Mean Temperature for September (°F)
64.8#
58.6
Temperature Thresholds
Number of Days
Normal
September 2015 Days with High Temperature of At Least 90°F
0
0.99
2015 Total Days with High Temperature of At Least 90°F
2
11.58
September 2015 Days with Low Temperature of 32°F or lower
1
1.70
September 2015 Days with Low Temperatures >= 70°F
1*
0.68
2015 Total Days with Days with Low Temperatures >= 70°F
0
3.00
*First September low of at least 70 since 1973    
September Temperature Extremes
Temperature(°F)
Date
Warmest High Temperature for September 2015 (°F)
89
September 4
Coldest High Temperature for September 2015 (°F)
63
September 18
Warmest Low Temperature for September 2015 (°F)
72
September 4
Coldest Low Temperature for September 2015 (°F)
32
September 30
Record Temperatures in September 2015
Temperature(°F)
Date
Old Record
No temperature records set
Precipitation (in)
This Year
Normal
September 2015 Precipitation (in)
2.24
3.46
Saint Cloud's Ten Rainiest/Driest Septembers
2015 Growing Season (April 1- September 30) Rainfall (in)
24.88 (+4.63 from average)
20.25
2015 Total Precipitation (in) (January 1 - September 30)
25.85 (+2.81 from average)
23.04
Precipitation Thresholds
Number of Days
Normal
September 2015 Days with Measurable (>= 0.01 inch) Precipitation
12
8.7
September 2015 Days with >= 0.10 inch Precipitation
6
5.6
September 2015 Days with >= 0.25 inch Precipitation
3
3.5
September 2015 Days with >= 0.50 inch Precipitation
1
2.0
September 2015 Days with >= 1.00 inch Precipitation
0
0.8
September Precipitation Extremes
Precipitation (in)
Date
Most Daily Precipitation in September 2015
0.64 inches
September 6
Record Precipitation in September 2015
Precipitation (in)
Date
Old Record
No records set

St. Cloud's Rainiest Years Through September

(Average Rainfall: 23.04 inches)

St. Cloud's Rainiest Growing Seasons (Apr-Sept)

(Average Rainfall: 20.25 inches)

Rank
Jan-Sept Rain (inches)
Year
Rank
Apr-Sept Rain (inches)
Year
 
36
25.85
2015
24
24.88
2015

 

 

The low rainfall is quite evident in the river level reports issued this week. The weekly DNR map shows streamflow in the lowest 10% from St. Cloud through most of Sherburne and Benton Counties. Currently, the Mississippi River level at St. Cloud is 4.17 feet, among the 5 lowest stages seen at this gauge (note that the third lowest levels were seen in September 2007, which isn't listed in the records). The Sauk River in Waite Park is down to only 1.17 feet, the sixth lowest stage seen on that river. (In August 2007, the Sauk River was down to 0.37 feet) The streamflow from the USGS shows that the Mississippi River basin is now below the 25% mark in the Mississippi River basin at most stations from Aitkin to the Twin Cities, in the St. Croix basin, and in the central and lower Minnesota River basin. Stream flow is now in the lowest 10% in north central Minnesota, including the Duluth, Grand Rapids, and Ely areas.

Meanwhile, temperature data shows that this September is the summer we didn't have. So far , St. Cloud is working on the warmest September in more than 70 years. Through yesterday, the average St. Cloud temperature has been 65.5°F, 7.1°F warmer than normal. If we remained this warm, this September would be the third warmest September in St. Cloud records and the warmest since 1931.

Historic temperature data provided courtesy of the Saint Cloud National Weather Service Office, and NOAA/NWS
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Send comments to: raweisman@stcloudstate.edu