Spring 2024 Frost/Freeze Info (NWS Hastings has started Frost Advisories/Freeze Warnings for the spring season)

**  PLEASE NOTE:  NWS Hastings will now start issuing Frost Advisories/Freeze Warnings for at least most of our 30-county coverage area **

- FOR THE MAJORITY OF OUR COVERAGE AREA (except for Valley/Greeley/Sherman/Dawson/Gosper/Furnas counties): The majority of our coverage area is now considered "fully eligible" for Frost Advisories/Freeze Warnings, although our forecasters can use discretion and possibly decide against a formal Advisory/Warning if frost/freeze conditions appear very marginal, brief in nature etc. 

- FOR THESE 6 COUNTIES IN OUR FAR NORTH/WEST COVERAGE AREA (Valley/Greeley/Sherman/Dawson/Gosper/Furnas):  At least for another week or so, these 6 counties are considered the least susceptible to frost/freezing conditions (given that vegetation is less "farther along" compared to areas farther south and east). As a result, we MIGHT opt against issuing a formal Warning/Advisory for these counties if it is a marginal frost/freeze situation. 

General Overview of Spring Frost/Freeze Information: 
The mid-April through early-May time frame typically features the final occurrence of freezing temperatures and/or frost of the spring season within our 30-county coverage area of south central Nebraska and north central Kansas. Based on 30-year averages, the date of the AVERAGE last spring freeze (32°-or-colder) ranges from around April 18th in far southeastern local communities (such as Beloit KS), to around April 24-29th in the Tri Cities (Grand Island/Hastings/Kearney), to around May 3-7th in far northern and western communities such as Greeley, Gothenburg and Cambridge. HOWEVER, after viewing the maps and tables contained in this story, it is readily apparent that the phrase "average last freeze date" is quite relative, as most sites exhibit a 5-9 week range between the earliest/latest last dates on record! 

Please refer to the wealth of information within the tabs below (including tables/maps of average last frost/freeze/hard freeze dates) to stay on top of the frost/freeze situation across our local area this spring. This includes the "Looking Ahead" section just below, which will highlight upcoming opportunities for frost/freeze within the next 7-10 days and also gives our insight as to when we believe the last frost/freeze of spring 2023 has most likely occurred. 

Looking Ahead: ** Some  Frost Possible Tues Night-Wed AM (April 24)...BUT Otherwise No Concerns Through At Least April 30th  ** 
(updated April 22...will likely not be updated again until April 26)

• April 23 (Mon night-Tues AM): 
  There are ZERO concerns for frost/freeze, as low temperatures will only bottom out in the 40s across nearly our entire coverage area. 
   
• April 24 (Tues night-Wed AM): 
  Although sub-freezing temperatures appear quite unlikely, temperatures could bottom out as low as 35-37° especially within several Nebraska counties mainly along/north of Interstate 80. Assuming clouds are not overly-thick, this COULD BE just cold enough to allow for some frost development (issuance of a Frost Advisory is possible, but not certain). 
   
• April 25-30 (Wed night-Thurs AM and beyond): 
  Temperatures will warm back up leading into a potentially active stretch of weather, with any frost/freeze concerns disappearing again for a while (perhaps even well into May?)
   
• ** PLEASE NOTE **: Sometimes (albeit rarely) a freeze can occur as late as mid-late May (this actually occurred just two years ago in 2022...when sub-freezing temps occurred on May 22!) 

Recapping Last Spring's (2023) Final Frost/Freeze:
- Spring 2023: For the majority of the NWS Hastings coverage area, the spring's final freeze(and especially hard freeze) occurred a little bit later than average. Most of our area observed it's final occurrence of 32º-or-colder at some point between April 23-May 4, and it's final occurrence of a hard freeze (28º-or-colder) between April 23-May 3. Particularly regarding the last hard freeze, this was generally 1-2 weeks later than the 30-year average. However, once the last freeze/hard freeze occurred in early-May, a pronounced warm-up kicked in and our entire area never really came close to seeing patchy frost thereafter (let alone a truly late freeze). 

• Frost/Freeze Definitions
• Local/Regional Last Frost/Freeze Maps & Table
• Freeze Susceptibility Maps
• Spring First Leaf/Bloom Index Maps

 

Before continuing, 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° (or colder), along with light winds, is usually needed to initiate frost formation. At least minor damage is possible to plants. One must keep in mind that frost is not guaranteed if the air is very dry and/or winds are roughly 8+ MPH.   The range of average dates for the LAST spring frost across across most of south central NE and north central KS is between May 1 - May 15. Freeze Freeze occurs when the temperature drops to 32°-or-lower. A freeze will damage many unprotected plants, especially if the temperature remains at-or-below freezing for several hours.   The range of average dates for the LAST spring freeze across most of south central NE and north central KS is between April 18 - May 7. Hard Freeze Hard freeze (per our local NWS definition) occurs when the temperature reaches 28°-or-lower. This usually means that most seasonal vegetation will be destroyed. In addition, there is a likelihood of damage to unprotected outdoor plumbing/un-drained sprinkler systems etc.    The range of average dates for the LAST spring hard freeze across across most of south central NE and north central KS is between April 9 - April 29.

 

 

South Central Nebraska and North Central Kansas
30-Year Average Last Frost/Freeze Dates (1994-2023)
(click images to enlarge)

Average Last 36° Date (Last Spring Frost) 1994-2023	Average Last 32° Date (Last Spring Freeze) 1994-2023	Average Last 28° Date (Last Spring Hard Freeze) 1994-2023

 

Median Dates of Last Spring Freeze & Hard Freeze (1991-2020)
(Midwestern Regional Climate Center)

Median Date of Last Spring 32° Freeze	Median Date of Last Spring 28° Hard Freeze

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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 our area!

Explanation of the following table:

• The first column lists 10 locations in south central Nebraska and 3 in north central Kansas with long histories as NWS Cooperative Observer sites (except for Grand Island and Hastings airports, which are automated systems). This is just a small sampling of dozens of official weather stations within the NWS Hastings coverage area, and these sites are generally organized down the column from north-to south. 
   
• The second column shows the average date of the LATEST spring observance of 28°, 32° and 36° temperatures during the most recent 30-year period from 1994-2023.
   
• The third and fourth columns reveal the earliest last freeze date and latest last freeze date (32° or colder) over the last 30 years. It is readily apparent that the phrase "average last freeze date" is quite relative, as most sites feature a 5-9 week difference between the earliest and latest dates! For some of these locations, the incredibly-early last freeze of spring 2012 (between March 9-11) was among the earliest on record. On the opposite spectrum, for several places the latest freeze of the last 30 years occurred in mid-May 2014. 
   
• The final column is a recap of LAST SPRING (2023), showing the last dates that 28°, 32° and 36° were observed. A blue-shaded date indicates that the last spring frost/freeze/hard freeze of 2023 occurred at least 10 days LATER than the 30-year average, while red-shaded dates indicate a last spring frost/freeze/hard freeze that was at least 10 days EARLIER than the 30-year average. 

Spring Frost/Freeze Data For South Central Nebraska + North Central Kansas
(based on 30-year averages from 1994-2023)

	Avg Last Spring Date: 28° or Colder 32° or Colder 36° or Colder	1994-2023 Earliest Last Date: 32° Or Colder	1994-2023 Latest Last Date: 32° Or Colder	Last Year (2023)   Last Occurrence: 28° Or Colder 32° Or Colder 36° Or Colder
Greeley	April 29 May 7 May 15	April 16, 2007	May 23, 2022	May 3 (28º) May 3 (28º) May 21 (35º)
Osceola	April 14 April 27 May 3	April 9, 2003	May 15, 2014	April 24 (24º) April 24 (24º)    May 3 (36º)
Gothenburg	April 21 May 3 May 15	April 11, 2012	May 25, 2002	April 25 (28º) May 2 (29º) May 3 (33º)
Kearney Airport (NWS Observer)	April 19 April 29 ​May 9	April 10, 2003	May 18, 2014	May 2 (28º) May 3 (29º) May 4 (33º)
Grand Island (airport)	April 14 April 26 ​May 6	April 9, 2003	May 17, 2014	May 2 (28º) May 3 (32º) May 3 (32º)
Holdrege	April 18 May 1 ​May 9	April 10, 2003	May 17, 2011	May 2 (28º) May 2 (28º) May 3 (33º)
Hastings (airport)	April 13 April 24 ​May 4	March 9, 2012	May 17, 2014	April 23 (24º) May 2 (30º) May 3 (33º)
Clay Center, NE	April 11 April 24 ​May 4	March 11, 2012	May 23, 2022	April 24 (25º) May 2 (32º) May 4 (36º)
Cambridge	April 20 May 4 ​May 13	April 8, 2003	May 21, 2015	May 1 (27º) May 4 (32º) May 4 (32º)
Hebron	April 13 April 24 ​May 4	March 11, 2012	May 16, 2014	April 24 (19º) May 4 (30º) May 4 (30º)
Smith Center, KS	April 11 April 20 May 1	March 10, 2012	May 11, 2020	April 24 (27º) April 24 (27º) May 2 (33º)
Plainville, KS	April 11 April 21 ​May 4	March 10, 2012	May 12, 2008	April 24 (26º) May 2 (32º) May 3 (33º)
Beloit, KS	April 9 April 18 ​May 1	March 11, 2012	May 4, 2004	April 23 (26º) April 23 (26º) May 3 (34º)

 

 

The Midwestern Regional Climate Center (MRCC) produces maps that update DAILY, depicting the most recent date that sites across the region that have fallen to at least 32° or 28° this spring. In addition, GRAY shaded areas = places that have NOT YET accumulated at least 150 Growing Degree Days (GDD/base 50º F) since Feb. 1st.

This generally means that gray-shaded areas have not yet become favorable for widespread plant/crop growth that could be significantly damaged by frost/freeze, while white-shaded areas are more likely to feature vegetation susceptible to more widespread freeze damage. 

                                                                                                            (click images to enlarge Nebraska and Kansas maps)

KS: Most Recent  32° or Below This Spring (dots) and areas most prone to have vegetation damaged by a freeze (WHITE shaded areas)	NE: Most Recent  32° or Below This Spring (dots) and areas most prone to have vegetation damaged by a freeze (WHITE shaded areas)
KS: Most Recent  28° or Below This Spring (dots) and areas most prone to have vegetation damaged by a freeze (WHITE shaded areas)	NE: Most Recent  28° or Below This Spring (dots) and areas most prone to have vegetation damaged by a freeze (WHITE shaded areas)

 

The USA-National Phenology Network (NPN) produces several maps that update DAILY, depicting the progression of particular types of spring vegetation across the nation, and how it compares to long-term averages. See their web page for much more detail and information, but the two maps highlighted below depict First Leaf Index Anomaly and First Bloom Index Anomaly. In short, this means they show the current status of some types of spring vegetation (first leaf-out or first-flowering) compared to long-term averages, giving an idea of whether spring is "ahead" of or "behind" schedule. 

                                                                (click images to enlarge)

Spring Leaf Index Anomaly	Spring Bloom Index Anomaly