Weather Data Shows Late April-May Cold Spells not that Uncommon in Nebraska

Weather Data Shows Late April-May Cold Spells not that Uncommon in Nebraska April 26, 2017

Freezing temperatures were reported at numerous locations across western Nebraska the morning of Wednesday, April 26, and Thursday, April 27. 

The lowest temperature reported Thursday morning at a National Weather Service (NWS) location was 21°F at Valentine.

The lowest temperature reported Wednesday morning at an NWS location was 27°F at Alliance and Sidney. The Nebraska State Climate Office Mesonet readings indicated hard freeze conditions at every Panhandle station, except Scottsbluff. Temperatures reached a low of 23°F at the Harrison station.

I have been receiving numerous calls in reference to how unusual this late freeze event is in comparison to the current climate normals period of 1981-2010 and since 2010. Table 1 lists data for selected stations across the state for these periods, including the average last freeze date, the range of last freeze dates, the lowest last freeze recorded, and the number of years when a freeze of 32°F to 28°F or lower was experienced during this period.

Table 1. Key frost and freeze records for selected sites in Nebraska. (Source: NOAA Cooperative Weather Observation Network)
Date of Average Last Freeze (2010-2016)Date of Average Last Freeze (1981-2010 Normals)Date Range of Freezes (2010-2016)Lowest May Temperature, Date (2010-2016)Events 32°F or below in May (2010-2016)Events 30°F or below in May (2010-2016)Events 28°F or below in May (2010-2016)
Alliance 5/17 5/21 5/6-5/29 22°F:  5/15/14 7 4 2
Broken Bow 5/13 5/11 4/23-5/22 26°F:  5/18/14 6 4 1
Hastings 4/20 4/22 3/9-5/17 28°F:  5/3/13 3 1 1
Kimball 5/13 5/13 5/6-5/20 29°F:  5/12/16 7 2 1
Lincoln 4/28 4/25 4/12-5/16 30°F:  5/16/14 3 2 0
McCook 5/6 5/1 4/10-5/16 25°F:  5/5/13 6 2 2
Norfolk 4/28 4/27 4/12-5/17 26°F:  5/3/11 3 2 1
North Platte 5/15 5/10 5/7-5/21 22°F:  5/5/13 6 4 2
Scottsbluff 5/7 5/7 4/18-5/17 21°F:  5/8/10 6 3 2
Valentine 5/15 5/11 6/6-5/23 27°F:  5/6/13 7 4 1

Our standard climatological comparison period is 1981-2010 and this will continue until 2022, when the new normals period of 1991-2020 begins. If we compare the average last freeze at the stations listed in Table 1 with the 1981-2010 normals period, the data would suggest that Hastings and Alliance averaged an earlier mean last freeze date during the 2010-16 period.

Of the remaining stations in Table 1, Scottsbluff and Kimball had the same average last freeze date during the 2010-2016 period as they did in the climatological period of 1981-2010.  Norfolk is one day later; Broken Bow, two days later; Lincoln, three days later;  Valentine, four days later, and McCook and North Platte, five days later. It appears, but is not conclusively determined, that the western half of the state experienced slightly later average last freeze dates during the 2010-16 period than in the 1981-2010 period.

Additional Resources

For daily updates on Nebraska weather, including soil temperatures, precipitation, GDD, and ET, see the Weather section of CropWatch. Information is provided by the Nebraska State Climate Office, which offers climate information, weather news and the Nebraska Mesonet, a statewide weather observation network with nearly 70 locations across Nebraska.

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