National Weather Service Weather Forecast Office

When you look at historical freeze data (32 degrees or lower), there is a tremendous variation from year-to-year and between any given location in south central Nebraska and north central Kansas. Last year, the fall of 2007 saw a delayed first freeze as October was wet for many areas. With the exception of the far northern parts of south central Nebraska (Greeley on 10/12/07), the first freeze didn't happen until the last 10 days of October, which was about three weeks behind schedule. 

Looking back for several decades, or even to the turn of the century, there is about a two month gap between the earliest and latest  freezes on record. One of the earliest freeze dates on record occurred the first week of September in 1974, as many locations in south central Nebraska and north central  Kansas dropped below the freezing mark on September 3rd. A weather map (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. 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	Greeley, NE Observation Form September 1974

The following is more information regarding frost and freezing conditions in south central Nebraska and north central Kansas.

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 needed for frost formation. Minor damage is possible to some plants.  A good portion of south central Nebraska had frosty conditions the morning of September 15, especially in low lying areas.

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