textproduct: Key West

KEY MESSAGES

-A potent cold front will race southeastward through the Florida Keys late today or this evening. In wake of the front, winds will clock northwest to north and freshen considerably. Near gale breezes will be possible. A Small Craft Advisory will likely be required for all Keys waters by this evening.

-The cold air mass behind the front along with one, possibly two, reinforcing front(s), have a good potential of keeping temperatures well below normal for the duration of the week.

-The reinforcing fronts will contribute to additional periodic and significant wind surges through through the week.

DISCUSSION

Issued at 400 AM EST Mon Jan 26 2026

Big changes are coming for Keys weather this week. To start things off, a potent cold front will drive southeastward across the Gulf and through the Keys today into tonight as a strong mid latitude trough moves through the eastern United States. Ahead of the front, a prefrontal trough will swing through South Florida and the Keys. Surface winds will firm up modestly out of the west. Highs today will be similar to yesterday at near 80 with dew points holding in the lower to mid 60s.

Low level convective support will be quite limited as the prefrontal trough barely scrapes across our area and the lower level flow becomes diffluent as the front reaches the Keys. Meanwhile upper level jet support will remain well to our north. As a result, despite high surface dew points, rain chances will remain slim at best. Behind this front, winds will surge out of the northwest to north, becoming windy. This front will inject much cooler and drier across the Keys. Expect highs and lows to slip 5 to 10 degrees below normal. The coolest lows will likely be found in the lee of South Florida due to radiational cooling and a South Florida land breeze. Dew points will plummet to near 50 Monday night and likely the 40s on Tuesday.

This will mark the beginning of a prolonged stretch of much cooler than normal weather, lasting through the remainder of the week. Highs will struggle to reach the upper 60s with lows falling broadly in the 50s. These persistent cold temperatures will be a consequence of the broad long wave trough remaining across the CONUS as a series of shortwaves swing through the eastern United States. In response, a couple of strong reinforcing surface highs driving southward through the eastern United States will reinforce the cool and dry air in place with additional northerly surges. There is a possibility that medium and long range temperatures may be cooler than forecast. This is due, in part, to the strength and duration of the cold air advection episodes, and the high likelihood that the shallow nearshore water temperatures will fall well into the 50s. For now, will hold forecast temperatures near the ensemble mean.

MARINE

Issued at 400 AM EST Mon Jan 26 2026

A strong cold front will blast through Keys waters beginning late this afternoon into tonight. This front will bring strong northwest to northerly breezes and building seas across the region. A Small Craft Advisory will be required for all Keys waters. Expect breezes to relax substantially on Tuesday as a surface high builds southeastward across Florida. However, additional wind surges are likely Tuesday night through Wednesday night due to a reinforcing cold front pushing southward across Keys waters.

CLIMATE

On this day in 1905, the high temperature in Key West was only 51F and the low temperature was 44F, both cold records for the date. With an average temperature of 47.5F, this ranks as a 4-way tie for the second-coldest day on record in Key West. Temperature records for Key West date back to 1873

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...None.