Fall's first freeze delayed by warm weather in these states. What to expect.

Fall's above normal temperatures are expected to linger across much of the United States this year, according to the Climate Central.

In a 2025 study, Climate Central analyzed the first freeze occurrences in 204 cities across the nation since 1970, finding that the first freeze often occurred much later in the season. Some central states, such as Kansas and Missouri, remain unseasonably warm.

Compared to the early 1970s, the first fall freeze now occurs an average of 12 days later. Given the changes in fall's temperatures, this shift is not surprising. The entire Lower 48 states experience warming fall temperatures, except for a few areas in the Midwest and Southeast.

When to expect fall's first freeze

Based on data from the U.S. Climate Normals from 1991 to 2020, the first freeze occurs when the surface air temperature is predicted to be 32 degrees or lower over a large area for a period of time that is climatologically important.

Typically the National Oceanic and Atmospheric Administration's "Historical Date of First Freeze: Median Date" map below, which is used for agricultural purposes, shows the average date of each region's first fall freeze. Meaning, in five of the 10 years that were documented, a freeze is expected to have occurred on or before the specified date.

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Warming trends delay first freeze in US

Fall days that are unusually warm have increased in 238 cities, or 98% of the 243 cities that were examined by Climate Central.

Fall warming has been greatest across the Plains, Northern Rockies and the Southwest, with fall temperatures in these areas increasing by 3-4 degrees (or more) since the early 1970s.

Impact of a freeze delay

A delayed first freeze sets off a chain of events that affect different regions in the United States. Because pollen and ragweed persist far longer into the fall, allergy sufferers are among those most immediately affected.

A freeze delay would also prolong the growth season, which can be beneficial for certain crops such as corn and soybeans but detrimental to others, such as fruit crops that need a certain amount of chill time.

In addition, pests like those obnoxious mosquitoes will have longer active seasons prior to the beginning of the first freeze.

Frost vs. freeze: What's the difference?

When temperatures start to drop below 32 degrees, the National Weather Service issues three types of alerts. When they are issued and how they are classified are as follows:

• Frost advisory: When temperatures are in the mid-30s (33 to 36 degrees), frost can be typically patchy. When temperatures are near or just above freezing, frost is more likely to occur and harm outdoor vegetation.
• Freeze watch or warning: When temperatures drop to 32 degrees or below, a freeze occurs. When low temperatures are predicted to be between 29 and 32 degrees, a freeze warning is issued.
• Hard freeze watch or warning: A hard freeze is more serious than a freeze, as the name suggests. These happen when temperatures persistently fall below 28 degrees, which kills off the majority of plants, plants, crops and insects.

SOURCE: Climate Central, NOAA, National Weather Service