Final Fall 2011 Frost/Freeze Recap (Updated Oct. 23)

 

Fall 2011 Frost/Freeze Recap:  Considering that "first fall-freeze dates" across South Central Nebraska and North Central Kansas can sometimes vary by 5 weeks or more from one year to another, it can be difficult to put one particular season into perspective. However, when taking into account 30-year averages of the first occurrence of 36 and 32 degrees (or colder), the majority of the NWS Hastings coverage area met these temperature thresholds later than average in Fall 2011. For 28 degrees (or colder), most northern areas generally north of Nebraska Highway 92 were several days later than average, southern portions of North Central Kansas were several days early, and many locations in between including the Tri-Cities ended up close to the average date. 

For most of the 30-county area, the first occurrence of both 32° and 28° held off until Oct. 19th or 20th, with the entire area experiencing the first widespread hard freeze of the season on the 20th. Only small portions of the area dropped to 32° or lower on an earlier-than-average date, most of these occurring on Sep. 22 or 23 with lows of 32° at Greeley and Cambridge, Nebraska, along with Alton, Kansas. The later-than average trend was especially true when focusing on the 36-degree frost threshold across southern portions of the area, with several sites such as Hebron and Plainville not reaching frost-worthy readings until 12-16 days past the average date. 

Please refer to the table located farther down the page for a wealth of information on average frost/freeze dates along with Fall 2011 results for 14 chosen locations across the NWS Hastings coverage area.  Based on the results in the table, here are just a few "highlights" involving locations that strayed at least 10 days from average frost/freeze dates:

36° (frost potential) or lower: Osceola (Oct. 15) was 15 days later than average and the 4th-latest occurrence in the past 31 years...Hebron (Oct. 15) was 14 days later than average and the 4th-latest in the past 31 years...Smith Center KS (Oct. 19) was 16 days later than average and the 3rd-latest in the last 31 years...Beloit KS (Oct. 19) was 14 days later than average and the 4th-latest in the last 31 years

32° (freezing) or lower: Loup City (Oct. 15) was 16 days later than average and the 2nd-latest occurrence in the past 31 years...Kearney airport (Oct. 19) was 14 days later than average and the 3rd-latest in the past 31 years...Grand Island airport (Oct. 19) was 11 days later than average...Alton KS (Sep. 22) was 11 days earlier than average...Cambridge (Sep. 22) was 10 days earlier than average

28° (hard freeze) or lower: Greeley (Oct. 20) was 14 days later than average and the 5th-latest in the last 31 years...



Before continuing, here are a few definitions:

Frost occurs when there is a solid deposition of water vapor from the air. Frost will form when solid surfaces are cooled below the dew point. An air temperature range of 33 to 36 degrees is usually needed to initiate frost formation. Minor damage is possible to some plants. One must keep in mind that a frost is not guaranteed at these temperatures if moisture in the air is lacking.

A Freeze occurs when the air temperature drops to 32 degrees. A freeze will result in significant damage to many unprotected plants, especially if the temperature remains at the freezing mark for a few hours


A Hard Freeze occurs when the temperature reaches 28 degrees. The growing season is considered to have all but ended when the temperatures drops to 28 degrees.  The range of typical dates for a hard freeze across south central Nebraska and north central Kansas is from the 1st through the 3rd week of October.

 
The Midwestern Regional Climate Center produces maps that update DAILY, depicting sites across the region that have fallen to at least 32 or 28 degrees so far this fall.  Check out statewide maps of Kansas and Nebraska by clicking on the images below. Again, these maps automatically update daily, and originate from the  Midwest Climate Watch website.

                                                                                                 (click images to enlarge)

                                 

Kansas observed 32 degrees or below so far this fall

Nebraska observed 32 degrees or below so far this fall

   

 Kansas observed 28 degrees or below so far this fall

Nebraska observed 28 degrees or below so far this fall 

 



Below is a table and set of maps, primarily focused on average dates for reaching particular temperature frost/freeze thresholds. However, there is often tremendous variation from year-to-year and between any given location across the area (see bottom of page for details on unusually early freeze in September 1974). 

Examining the table below, here are a few things to consider:

- The first column lists 10 chosen locations in south central Nebraska and 4 in north central Kansas with long histories of being NWS Cooperative Observer sites (except for Grand Island and Hastings airports, which are automated systems). This is just a small sampling of dozens of observing locations within the NWS Hastings coverage area, and these sites are generally organized from north to south down the column. Click HERE for a map of the 30-county NWS Hastings County Warning Area.

- The second column shows the strict numerical average date of the first observance of 36, 32, and 28 degree temperatures. Corresponding to the latest issuance of 30-year climate normals, this data covers the 1981-2010 period. Please note that differences in average freeze dates between these locations are NOT purely a function of "north versus south", but also depend on a variety of factors including local terrain. For example, although Alton, KS, is located well south of Grand Island, NE,  Alton typically sees freezing temperatures sooner in the fall thanks to efficient cold air drainage along the South Fork Solomon River valley. 

- The second and third columns reveal the earliest and latest freeze dates (32 degrees or colder) observed during the past 30 years. It is readily apparent that the phrase "average freeze date" is quite relative, as most sites have a 5-7 week difference between the earliest and latest dates. For the majority of locations, the earliest freeze during the past 30 years occurred during September 1991 or 1993. On the opposite spectrum, for some locations one of the latest freezes on record held off until early November in 1998.

- The final column on the right reveals the date that 36, 32 and 28-degree thresholds were first met in FALL 2011 within the area. A blue-shaded date indicates a location that reached a temperature threshold at least 7 days before the average date, while red-shaded dates indicates that this threshold was met at least 7 days later than the average date. 


 Climatological Data For South Central Nebraska and North Central Kansas
(All Averages Based on 30-year observations from 1981-2010)

 

Average First 
Date of...

36 Degrees
32 Degrees
28 Degrees

Earliest Date 
1981-2010 of...

32 Degrees
or Colder 

Latest Date 
1981-2010 of...

32 Degrees
or Colder 

First Fall 2011  
Occurence of...

36 Degrees
32 Degrees
28 Degrees

 Greeley

Sep. 23
Sep. 27
Oct. 6

Sep. 15,1993 

Oct. 14,1997

Sep. 15 (36°)
Sep. 23 (32°)
Oct. 20 (19°)

 Loup City

Sep. 24
Sep. 30
Oct. 10

Sep. 13, 1989

Oct. 25, 2003

Sep. 22 (35°)
Oct. 15 (32°)
Oct. 20 (21°)

 Osceola

Sep. 30
Oct. 9
Oct. 14

Sep. 19, 1991

Nov. 3, 1998

Oct. 15 (35°)
Oct. 19 (30°)
Oct. 20 (23°)

 Kearney Airport
(NWS Observer)

Sep. 27
Oct. 5
Oct. 16

Sep. 17, 1981

Oct. 25, 1997 

 Sep. 22 (36°)
Oct. 19 (31°)
Oct. 20 (22°)

 Grand Island
 (airport)

Sep. 29
Oct. 8
Oct. 15

 Sep. 19, 1991

 Oct. 26, 2007

 Sep. 22 (36°)
Oct. 19 (29°)
Oct. 20 (22°)*

 York

Oct. 3
Oct. 12
Oct. 21

 Sep. 19, 1991

Nov. 4, 1998

 Sep. 22 (36°)
Oct. 19 (27°)
Oct. 19 (27°)

 Cambridge

Sep. 25
Oct. 2
Oct. 12

Sep. 15, 2008

 Oct. 25, 1997

Sep. 22 (32°)
Sep. 22 (32°)
Oct. 20 (22°)

 Holdrege

Oct. 3
Oct. 10
Oct. 21

Sep. 19, 1991

Nov. 4, 1998

Sep. 22 (33°)
Sep. 30 (31°)
Oct. 19 (28°)

 Hastings
(NWS Office/airport)

Sep. 29
Oct. 9
Oct. 19

Sep. 19, 1991

 Nov. 3, 1998

Sep. 22 (36°) / Oct. 18 (35°)
Oct. 19 (28°) / Oct. 19 (31°)
Oct. 19 (28°) / Oct. 20 (22°)*

 Hebron

Oct. 1
Oct. 11
Oct. 20

 Sep. 19, 1991

 Oct. 26, 1997
 Oct. 26, 2007

Oct. 15 (35º)
Oct. 19 (32º)
Oct. 20 (23°)

 Smith Center KS

Oct. 3
Oct. 13
Oct. 20

 Sep. 21, 1983

 Nov. 4, 1998

Oct. 19 (34º)
Oct. 20 (26°)
Oct. 20 (26°)

 Alton KS

Sep. 26
Oct. 3
Oct. 13

 Sep. 15, 1993

 Oct. 23, 2007

Sep. 22 (32°)
Sep. 22 (32°)
Oct. 20 (22°)

 Plainville KS

Oct. 7
Oct. 17
Oct. 27

Sep. 20, 1995

 Nov. 4, 1998

Oct. 19 (32º)
Oct. 19 (32º)
Oct. 20 (27°)

 Beloit KS

Oct. 5
Oct. 17
Oct. 26

 Sep. 22, 1995

 Nov. 10, 1998

Oct. 19 (34º)
Oct. 20 (24°)
Oct. 20 (24°)

 * Grand Island and Hastings airports actually dropped below 28 degrees on the late evening of the 19th, but the table reflects the overnight low temperature recorded on the morning of the 20th to better correspond with NWS Cooperative Observer data which reflects a 24-hour period ending around 7 AM


 South Central Nebraska and North Central Kansas 
Average First Frost/Freeze Dates (1981-2011)

(click images to enlarge)

Average 36-Degree Date (Frost)
Average 32-Degree Date (Freeze)
Average 28-Degree Date (Hard Freeze)


Nebraska Frost/Freeze Averages (maps courtesy NWS Omaha/Valley)
(click images to enlarge)

 Average date of first 36-degree temps

 Average date of first 32-degree temps

 Average date of first 28-degree temps

 


 

 Average First Fall 32-Degree Dates for Kansas (courtesy the Kansas State Climatologist)

(click to enlarge)

 


 A Look Back At The Unusually Early Frost/Freeze of September 1974:

One of the earliest freezes on record in parts of South Central Nebraska occurred the first week of September in 1974, as many locations dropped below the freezing mark on September 3rd.  A surface weather map (see below, far left thumbnail image) from September 3, 1974 depicted just why such cold temperatures were observed. An unseasonably cold airmass roared into the region behind a strong cold front. Eventually, surface high pressure set up over the region, creating an ideal situation for a record early freeze. In fact, note the hand written comment "Record early damaging frosts, corn belt area" at the top of the weather map. Cooperative Observation forms for Gothenburg and Greeley, Nebraska are also shown below. The Gothenburg observer noted "Clear. Froze. Ice. Crop Damage" on the right side of the form on the 3rd. Finally, it is interesting to note both Gothenburg and Greeley recorded freezing temperatures again just ten days later on September 13, 1974.  

September 3, 1974 Weather Map

(click to enlarge)

Gothenburg, NE Observation Form
September 1974

(click to enlarge)

Greeley, NE Observation Form
September 1974

(click to enlarge)

 

This page was composed by the staff at the National Weather Service in Hastings, Nebraska.

 



Return to News Archive

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.