Freeze Forecasts
The risk of damaging freeze events is reduced this winter (2007/2008) due to a developing La Niña.
Background - Of the dozen or so devastating freezes that have impacted the citrus industry and other agriculture concerns over the last century or in the Southeast, nearly all of them occurred during times of Neutral conditions in the Pacific Ocean, when there is neither El Niño or La Niña present. The table below lists the impact freezes and the corresponding Phase of the Pacific Ocean.
| Freeze Event | Climate Phase |
|---|---|
| December 1894 | Neutral |
| February 1899 | Neutral |
| December 1934 | Neutral |
| January 1940 | Neutral |
| December 1962 | Neutral |
| January 1977 | El Niño |
| January 1981 | Neutral |
| January 1982 | Neutral |
| December 1983 | Neutral |
| January 1985 | Neutral |
| December 1989 | Neutral |
| January 1997 | Neutral |
Reduced Risk
An in-depth analysis of weather observations from across the Southeast over the last 60 years shows that the risk of severe freezes in Florida is up to three times greater during Neutral conditions in the Pacific Ocean. Being in a La Nña this winter, that risk should be reduced. Keep in mind that severe freezes are unique weather events, and there's always a chance that they could occur in any phase of Pacific Ocean conditions. For details on probabilities for specific extreme temperatures in your county, see the Climate Risk Tool
Early Season Freezes
We have found no connection between the Pacific Ocean and first frost/freeze dates. Presented here are the expected dates of first freezes at the 10%, 50%, and 90% probability levels. 50% probability maps show the average dates when the first 32°F freeze occurs in your county. In practical terms it means that half of the freezes occurred before that date and half after that date. 10% probability maps show how soon the first freeze can occur. In practical terms it means that in 1 out of 10 years, the first freeze will occur that soon. 90% probability maps show the other side of the probability distribution. In practical terms it means that in 9 out 10 years, the first freeze occurs before that date, or only in 1 out 10 years the first freeze will occur by or after that date.
Late Season Freezes
We have found no connection between the Pacific Ocean and last freeze dates. Presented here are the expect dates of last freezes at the 10%, 50%, and 90% probability levels. 50% probability maps show the average dates when the last 32°F freeze occurs in your county. In practical terms it means that half of the freezes occurred before that date and half after that date. 10% probability maps show how late the last freeze can occur. In practical terms it means that in 1 out of 10 years, the last freeze will occur by that date or later. 90% probability maps show the other side of the probability distribution. In practical terms it means that in 9 out 10 years, the last freeze occurs by that date or later, or only in 1 out 10 years the last freeze will occur that soon.
