Florida's Frost Dates

Whether you're planning a vegetable bed, updating your landscaped yard or wondering when to bring container plants indoors, knowing the likely frost dates for your area is a must for any gardener. Find out how average frost dates are calculated, what they are for your area, and how to protect tender plants if there's a risk of frost.

Frost and Freezes

Frost and freeze are both weather conditions that can cause problems for your plants. But did you know that frost can occur a few degrees above freezing temperatures? Here are the three cold weather alerts that you need to pay attention to so that you can keep your outdoor plants happy.

Frost

Frost occurs when water vapor in the air gets cold enough to freeze as it settles on surfaces. In warmer temperatures, this vapor might settle as dew. Frost can even form when the air temperature is at 36 or 37 degrees Fahrenheit. This is because various factors can mean that the temperature at ground level is a few degrees colder than the air temperature, which is usually measured with a thermometer two meters above the ground.

For many plants, frost will only cause minor issues, but it can kill or damage any flowers or buds and can cause problems for sensitive plants. Covering plants or moving them indoors will protect them if frost advisories are issued.

Freeze

A freeze occurs when the air temperature dips to 32 degrees Fahrenheit or lower for several hours. Many plants will be damaged by these conditions. The plant cells themselves freeze at this temperature, which can lead to brown or black patches and potential wilting. Sometimes the damage can affect the entire plant.

Outdoor plants can be covered with bedding, towels or tarps to protect them during a freeze. These should be left in place overnight but removed in the morning to avoid trapping condensation.

Hard Freeze

A hard freeze means temperatures of 28 degrees Fahrenheit or lower, for four or more consecutive hours. These conditions will cause similar damage to a freeze, but in this case, temperatures are so cold that covering plants is unlikely to help. If possible, bring delicate plants indoors during a hard freeze.

What Are Average Frost Dates?

Average frost dates are calculated from historic weather forecasts. They are not designed to give an exact date for the first fall frost and last spring frost of the year, but to tell gardeners when nightly frosts are likely to begin and end for the season.

Depending on what you want to grow, you will need to wait a specified amount of time after the last frost date before you plant seeds or bring seedlings outside. The average last spring frost date for your region can tell you when the growing season approaches for your chosen plants.

How to Use Frost Dates

Bear in mind that the frost dates you will find on various websites, including the USDA's useful plant hardiness zone map, are taken from an average of recorded frost dates in previous years. This means that, although they can give a good general idea of when safe temperatures will be reached, these dates are not designed to be an accurate prediction. It's still important to keep an eye on nightly temperatures.

Hardy perennial plants - that is, those that are hardy for your Zone - should survive any expected nightly frosts or freezes. However, if you are growing plants that are hardy only in a warmer Zone, you may need to take extra measures to ensure they are not damaged. If you're not sure what Hardiness Zone you live in, this website may help you find out.

For example, if you live in North Central Florida, in Zone 9b, but are growing plants that are hardy in Zone 10, you would need to pay attention to frost dates and the weather forecast. If a frost event is expected, you will need to cover those tender plants with old bedding, towels, or frost fabric. Alternatively, if they are in containers, you could bring them indoors.

In spring, check local weather forecasts, and wait until you see a safe temperature several nights in a row before bringing tender plants outside.

Florida's Frost Dates

In North Florida, the first possible expected frost date of fall is November 1. The last expected frost date in spring is February 28. These dates represent the earliest and latest expected frost dates for the entire state. Of course, where in Florida you live will make a big difference to expected frost dates in your local area.

Here are the frost dates for some of Florida's major cities, sourced from the Farmer's Almanac. These will give you a rough idea of the usual frost range where you live. They are worked out at 30% accuracy, meaning there is just a 30% chance of seeing frost earlier in fall and later in spring.

• Tallahassee's first fall frost is November 13 and last spring frost is March 19.
• Jacksonville's first fall frost is December 24 and last spring frost is Feb 15.
• Gainesville's first fall frost is November 24 and last spring frost is March 13.
• Daytona Beach can expect frost from December 31 until February 15.
• Orlando can see frost from January 3 until January 30.
• Tampa's first frost date is January 3 and last frost is January 31.
• Sarasota may expect frost from January 2 until January 27.
• Fort Myers has a first frost date of January 7 and a last frost date of January 28.
• West Palm Beach and Miami have no data as frost and freezes are extremely rare in those areas.

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