Final Spring 2012 Frost/Freeze Recap

Spring 2012 Frost/Freeze Recap: Now that we are well into the blazing heat of summer, it's time to take a look back at the spring frost/freeze season, and how unusual it was for South Central Nebraska and North Central Kansas...

Although "spring final-freeze dates" often show tremendous variation from year-to-year, there was no doubt that spring 2012 featured some of the earliest final-freezes on record within the 30-county NWS Hastings coverage area, resulting in an incredibly early start to the growing season. Based on the final occurrence of both hard freeze (28 degrees or colder) and freeze (32 degrees or colder), the majority of the area last reached these marks a notable 20-45 DAYS EARLIER THAN AVERAGE. This was especially the case across north central Kansas and near the state line in far south central Nebraska, where most places recorded their last 32-degree readings 40-45 DAYS EARLIER THAN AVERAGE. Based on 30-year averages from 1981-2010, the majority of the NWS Hastings coverage area can typically expect to freeze for the last time between the last week of April and the first week of May.

For most of the 30-county area, the last occurrence of 28° or colder occurred way back on March 9th or 10th, except for some places in northern and western portions of south central Nebraska that again reached this mark on April 8th or 11th. The following table reveals that places such as Hastings and Hebron recorded their earliest final-freeze date (32°) on record!

Location

Average Last Spring Freeze Date
(1981-2010)

Last Freezing Temperature
Recorded THIS SPRING

Earliest Last Freeze Date
On Record (32°)

Latest Last Freeze Date
On Record (32°)

Grand Island

April 25

April 11 (30°)

April 5 (1984, 1977, 1969)

May 29, 1947

Hastings

April 24

March 9 (22°)

March 9, 2012

May 29, 1947

Kearney

April 30

April 11 (31°)

April 3, 1930

May 29, 1947

Hebron

April 25

March 10 (32°)

March 10, 2012

May 29, 1947


For a wealth of information on several other sites across the area, please refer to the larger table located farther down the page. Based on results from the table below, here are just a few "highlights" involving locations that strayed at least 15 days from average final frost/freeze dates this year:

Final occurrence of 28° (hard freeze) or lower:
Greeley (April 11) was 17 days earlier than average, and the 3rd-earliest in the past 30 years
Kearney (March 10) was 43 DAYS EARLIER THAN AVERAGE, and the earliest of at least the past 30 years
Grand Island (March 9) was 35 days earlier than average, and the earliest of at least the past 30 years
Cambridge (April 8) was 15 days earlier than average, and tied with 1985 for the earliest of the past 30 years
Holdrege (March 10) was 34 days earlier than average, and the earliest of at least the past 30 years
Hastings airport (March 9) was 36 days earlier than average, and the earliest of at least the past 30 years
Hebron (March 9) was 34 days earlier than average, and the earliest of at least the past 30 years
Smith Center KS (March 9) was 31 days earlier than average, and the earliest of at least the past 30 years
Alton KS (March 9) was 42 DAYS EARLIER THAN AVERAGE, and the earliest of at least the past 30 years
Plainville KS (March 9) was 34 days earlier than average, and the earliest of at least the past 30 years
Beloit KS (March 9) was 30 days earlier than average, and the earliest of at least the past 30 years

Final occurrence of 32° (freezing) or lower:
Kearney airport (April 11) was 19 days earlier than average, and the 2nd-earliest occurrence in the past 30 years
Hastings airport (March 9) was 46 DAYS EARLIER THAN AVERAGE, AND THE EARLIEST ON RECORD
Hebron (March 10) was 46 DAYS EARLIER THAN AVERAGE, AND THE EARLIEST ON RECORD
Smith Center KS (March 10) was 43 DAYS EARLIER THAN AVERAGE, and the earliest in the past 30 years
Plainville KS (March 10) was 46 DAYS EARLIER THAN AVERAGE, and the earliest in the past 30 years
Beloit KS (March 11) was 40 DAYS EARLIER THAN AVERAGE, and the earliest in the past 30 years

Final occurrence of 36° (frost potential) or lower:
Smith Center KS (April 8) was 24 days earlier than average, and the earliest of at least the past 30 years
Plainville KS (April 11) was 24 days earlier than average, and earliest of at least the past 30 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. The range of average dates for the last occurrence of spring frost across south central Nebraska and north central Kansas is between May 1 - May 16.

A Freeze occurs when the air temperature drops to 32 degrees or lower. A freeze will result in significant damage to many unprotected plants, especially if the temperature remains at the freezing mark for a few hours. The range of average dates for the last freeze of the spring across south central Nebraska and north central Kansas is between 
April 20 - May 4.


A Hard Freeze occurs when the temperature reaches 28 degrees or lower for at least a few hours. It usually means that many types of plants and most seasonal vegetation will be destroyed. The range of average dates for the last hard freeze of the spring across south central Nebraska and north central Kansas is between April 8 - April 28.


 Detailed Frost/Freeze Table and Climatological Maps:

Below is a table and set of maps, primarily focused on average dates for the last occurrence of particular frost/freeze thresholds in the spring. However, please keep in mind there is sometimes tremendous variation from year-to-year and between any given location across the area. Regarding the table, here are some things to consider:

- The first column lists 9 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 average date of the latest observance of 28, 32, and 36 degree temperatures during the 30-year period from 1981-2010. 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, Alton, KS, in Osborne County is typically prone to later freezes in the spring than some locations farther north, thanks to efficient cold air drainage along the South Fork Solomon River valley.

- The third and fourth columns reveal the earliest last freeze date and latest freeze date (32 degrees or colder) observed during the past 30 years, covering the period 1983-2012. It is readily apparent that the phrase "average freeze date" is quite relative, as most sites have a 5-8 week difference between the earliest and latest dates. For the majority of locations, the earliest last freeze during the past 30 years occurred between March 9 and April 10. On the opposite spectrum, for many locations the latest freeze during the past 30 years was between May 13-29. 

- The final column on the right reveals the date that 28, 32 and 36-degree thresholds were LAST met in SPRING 2012 within the area. A blue-shaded date indicates that a location met one of these temperature thresholds at least 7 days later than the average date, while red-shaded dates indicates that this threshold was last met at least 7 days earlier than the average date. It is readily apparent that in spring 2012 most locations recorded their last freezing temperatures considerably earlier than normal.


 Climatological Spring Freeze Data For South Central Nebraska and North Central Kansas
(average dates based on 30-year observations from 1981-2010)

 

Average Last
Date of...

28 Degrees
32 Degrees
36 Degrees

Earliest Last Date
1983-2012 of...

32 Degrees
or Colder

Latest Date
1983-2012 of...

32 Degrees
or Colder

Latest Spring 2012
Occurence of...

28 Degrees
32 Degrees
36 Degrees

Greeley

April 28
May 4
May 16

April 15, 2007

May 19, 2000

April 11 (23°)
May 9 (32°)
May 9 (32°)

Osceola

April 14
April 26
May 4

March 31, 1991

May 15, 1983

April 11 (28°)
April 23 (32°)
April 23 (32°)

Kearney Airport
(NWS Observer)

April 22
April 30
May 10

April 9, 2003

May 28, 1992

March 10 (27°)
April 11 (31°)
May 9 (35°)

Grand Island
(Airport)

April 13
April 25
May 4

April 5, 1984

May 13, 1997

March 9 (22°)
April 11 (30°)
April 23 (33°)

York

April 8
April 21
April 29

April 1, 1991

May 13, 1997

April 11 (28°)
April 23 (30°)
May 9 (36°)

Cambridge

April 23
May 3
May 14

April 14, 1985

 May 29, 1992

April 8 (26°)
May 9 (31°)
May 9 (31°)

Holdrege

April 13
April 28
May 6

April 9, 2003
April 9, 1985

May 29, 1992

March 10 (23°) 
May 9 (31°)
May 9 (31°)

Hastings
(NWS Office/Airport)

April 14
April 24
May 2

March 9, 2012

May 14, 2004

Mar. 9 (23°) / Mar. 9 (22°)
Mar. 9 (23°) / Mar. 9 (22°)
Apr 23 (34°)Apr 23 (34°)

Hebron

April 12
April 25
May 3

March 10, 2012

May 13, 1997

March 9 (22º)
March 10 (32º)
April 23 (33°)

Smith Center KS

April 9
April 22
May 2

March 10, 2012

May 15, 1983

March 9 (21°)
March 10 (22°)
April 8 (34°)

Alton KS

April 20
April 29
May 9

April 8, 1985

May 29, 1992

March 9 (19°) 
May 9 (31°)
May 9 (31°)

Plainville KS

April 12
April 25
May 5

March 10, 2012

May 11, 2008

March 9 (22°)
March 10 (29°)
April 11 (36°)

Beloit KS

April 8
April 20
May 1

March 11, 2012

May 6, 1989

March 9 (22°)
March 11 (32°)
April 23 (35°)

 


 

 Median Dates of Last Spring Freeze and Hard Freeze (1981-2010)
(Midwestern Regional Climate Center)

(click images to enlarge)

Median Date of Last 32-Degree Freeze Median Date of Last 28-Degree Hard Freeze

 


 

South Central Nebraska and North Central Kansas
Average Last Frost/Freeze Dates (1981-2010)

(click images to enlarge)

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


 


 

Nebraska Average Date of Last Spring Freeze
(map courtesy NWS Omaha/Valley
)

(click image to enlarge)

Average date of last 32-degree temps in the spring

 

Kansas Average Date of Last Spring Freeze
(courtesy of the
Kansas State Climatologist)

(click to enlarge)

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

 




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