Fall 2021 Frost/Freeze Info (as of Nov. 1: NWS Hastings has DISCONTINUED all Freeze Warnings for the fall )

** PLEASE NOTE: as of Nov. 1: NWS Hastings HAS DISCONTINUED FREEZE WARNINGS THIS FALL for our entire 30-county coverage area. Freeze Warnings and Frost Advisories will again become possible as needed when the growing season starts up again in spring 2022 **

According to longer-term averages, the NWS Hastings coverage area of south central Nebraska and north central Kansas is NOW ACTUALLY PAST THE 1-3 WEEK PERIOD THAT FEATURES THE AVERAGE DATE OF THE FIRST FALL HARD/KILLING FREEZE!

Of course, as outlined extensively in the data presented below, the first fall frost/freeze dates can vary tremendously from one year to the next, and just within the past 30 years, "first freezes" have ranged anywhere from mid-September to early-November.
-- Last year in 2020, most of our coverage area had its first true fall freeze and/or hard freeze sometime between Oct. 16-26. --

Please refer to the wealth of information within the tabs below (including tables and maps of average frost/freeze/hard freeze dates) to "stay on top" of the frost/freeze situation across the local area this fall. This includes the "Looking Ahead" section just below, as it will highlight any nights within the next 7-10 days that appear to hold frost/freeze potential (if any). Finally, check out the last tab for a glance back at the RECORD-EARLIEST frost/freeze that parts of our area experienced on Sep. 3, 1974!

Looking Ahead: ** Fall 2021 Potential-For-FREEZE Forecast ** (valid through Nov. 2):
(updated: Nov. 1)

As of Nov. 1: this forecast section has been DISCONTINUED for the fall. Now that we are into November and WELL PAST the average first freeze dates, sub-freezing temperatures should no longer be considered unusual. In addition, NWS Hastings will no longer issue Freeze Warnings this fall.

** The 2021 growing season has EFFECTIVELY ENDED **

Looking Back to Last Fall (2020):

Overall, the first freeze/hard freeze of Fall 2020 was fairly typical and "on schedule", although if anything it did lean slightly later than 30-year averages. Generally speaking, most areas recorded their first freeze and/or hard freeze sometime during the Oct. 16-26 time frame, although a few mainly northern/western local spots (such as Greeley/Ord/Cambridge) observed "barely-freezing" temperatures as early as Sep. 29-Oct. 2. Even a small part of our southeastern coverage area (particularly Thayer/Fillmore counties) saw slightly-freezing temperatures during this earlier time frame.

Frost/Freeze Definitions
Local/Regional First Frost/Freeze Maps & Table
September 1974 Record Early Freeze

Before continuing on, here are a few definitions...

Frost

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°- 36°, along with very light winds, is usually needed to initiate frost formation. At least minor damage is possible to plants. One must keep in mind that a frost is not guaranteed if humidity isn't high enough and/or winds are roughly 8+ MPH.

The range of average dates for the first fall frost across most of
south central Nebraska and north central Kansas is between Sep. 24 - Oct. 8.

Freeze

Freeze occurs when the temperature drops to 32°-or-lower. A freeze will result in significant damage to many unprotected plants, especially if the temperature remains at-or-below freezing for several hours.

The range of average dates for the first fall freeze across most of
south central Nebraska and north central Kansas is between Oct. 1 - Oct. 16.

Hard Freeze

Hard freeze occurs when the temperature reaches 28°-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 first hard freeze of the fall across most of
south central Nebraska and north central Kansas is between Oct. 9 - Oct. 26.

South Central Nebraska and North Central Kansas
30 Year Average First Frost/Freeze Dates (1990-2019)
(click image to enlarge)


Average 36° Date (First Possible Frost)	Average 32° Date (First Freeze)	Average 28° Date (First Hard Freeze)

Below is a table focused on the average dates for reaching particular frost/freeze temperature thresholds. Keep in mind, there is often tremendous variation from year-to-year and between any given location across the area.

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

The first column lists 10 locations in south central Nebraska and 3 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.
The second column shows the average date of the first observance of 36°, 32° and 28° temperatures during the most recent 30 year period from 1991-2020.
The third and fourth columns reveal the earliest first freeze date and latest first freeze date (32° 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 between Sep. 13-20 in years such as 2014/1995/1991. On the opposite end of the spectrum, for many locations the latest freeze during the past 30 years occurred between Oct. 25-Nov. 4 in years such as 1997/1998/2015.
The final column on the right is a "work in progress", and reveals the date that 36°, 32° and 28° thresholds were first met THIS FALL within our area. A blue-shaded date indicates that a location reached a temperature threshold at least 10 days before its average date, while red-shaded dates indicate that this threshold was first met at least 10 days after its average date.

Fall Frost/Freeze Data For South Central Nebraska and North Central Kansas
(based on 30-year averages from 1991-2020)

	Avg First Fall Date Of: 36° Or Colder 32° Or Colder 28° Or Colder	1991-2020 Earliest Date Of: 32° Or Colder	1991-2020 Latest Date Of: 32° Or Colder	First Fall 2021 Date Of: 36° Or Colder 32° Or Colder 28° Or Colder
Greeley	Sep. 24 Oct. 1 Oct. 9	Sep. 15, 1993	Oct. 16, 2015	Sep. 22 (34º) Oct. 17 (30º) Oct. 22 (28º)
Osceola	Oct. 4 Oct. 13 Oct. 19	Sep. 19, 1991	Nov. 3, 1998	Oct. 14 (36º) ? ?
Gothenburg	Sep. 28 Oct. 4 Oct. 17	Sep. 19, 2006	Oct. 27, 2013	Oct. 14 (30º) Oct. 14 (30º) Oct. 16 (26º)
Kearney Airport (NWS Observer)	Sep. 29 Oct. 9 Oct. 19	Sep. 19, 1991	Oct. 25, 1997	Oct. 14 (33º) Oct. 22 (32º) ?
Grand Island (airport)	Oct. 1 Oct. 10 Oct. 18	Sep. 19, 1991	Oct. 26, 2007	Oct. 14 (35º) Oct. 16 (32º) ?
Holdrege	Oct. 3 Oct. 11 Oct. 19	Sep. 20, 1991	Nov. 4, 1998	Oct. 14 (30º) Oct. 14 (30º) ?
Hastings (airport)	Oct. 3 Oct. 12 Oct. 20	Sep. 20, 1991	Nov. 3, 1998	Oct. 14 (33º) ? ?
Geneva	Oct. 6 Oct. 15 Oct. 22	Sep. 19, 1991	Nov. 3, 1998	Oct. 14 (36º) Oct. 16 (32º) ?
Cambridge	Sep. 27 Oct. 3 Oct. 15	Sep. 13, 2014	Oct. 25, 1997	Sep. 22 (36º) Oct. 14 (30º) Oct. 16 (28º)
Hebron	Oct. 2 Oct. 12 Oct. 21	Sep. 19, 1991	Oct. 29, 2015	Oct. 14 (35º) Oct. 16 (31º) ?
Smith Center, KS	Oct. 6 Oct. 16 Oct. 24	Sep. 22, 1995	Nov. 4, 1998	Oct. 15 (36º) Oct. 16 (32º) ?
Plainville, KS	Oct. 7 Oct. 16 Oct. 24	Sep. 20, 1995	Nov. 3, 1998	Oct. 14 (36º) Oct. 21 (32º) ?
Beloit, KS	Oct. 8 Oct. 15 Oct. 26	Sep. 13, 2014	Nov. 10, 1998	Oct. 16 (33º) Oct. 30 (32º) ?

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

One of the earliest frost and/or freezes on record in parts of central/south central NE and north central KS occurred the first week of September 1974, as many locations dropped below the freezing mark on Sept. 3rd! Just as a few examples: NWS cooperative observers in Beaver City/Ravenna reported morning lows as cold as 29º. Even in our KS coverage area, Webster Dam fell to 32º.

A surface weather map (below left) from Sept. 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 handwritten comment "Record early damaging frosts, corn belt area" at the top of the weather map. The original NWS cooperative observation forms from Gothenburg and Greeley NE are also depicted below. The Gothenburg observer noted "Clear. Froze. Ice. Crop Damage" on the right side of the form on the 3rd. It's also interesting to note that both Gothenburg and Greeley recorded freezing temperatures again just 10 days later on Sept. 13!


Sep. 3, 1974 Weather Map	Gothenburg, NE Observation Form	Greeley, NE Observation Form

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