textproduct: Key West

KEY MESSAGES

- Rain and thunder chances will only be slight (near 20%) through the rest of the weekend. - While highs will be seasonably warm in the upper 80s through next week, lows will remain warmer than normal, providing little relief from the heat in the overnight hours.

- The next opportunity for an uptick in active weather looks to be the middle of the week.

DISCUSSION

Issued at 1020 AM EDT Sun May 31 2026 The month of May is coming to an end across the Florida Keys with summertime conditions in full swing. The morning KKEY sounding sampled an environment with a near-record high PWAT, near 2.3", for the day. Dew points across the Keys are in the mid to upper 70s amidst light and variable winds. Outdoor conditions are muggy and stagnant. Expect heat indices in the upper 90s to 100s today. Heat risk will be a concern, so try to find relief from the weather where one can.

There are a few quirks to the ongoing conditions across the Keys. Persistent southwesterly winds in the lower atmosphere are responsible for directing deep layers of moisture in the Caribbean towards the Keys, as sampled by the 00Z KKEY sounding, but those winds are also directing a plume of Saharan dust towards South Florida. The sounding sampled a dry layer above the surface but below 500 mb. A complicating factor is that while light and variable winds are forecast, a general trend towards southwesterlies is observed across the island chain. A reverse cloud line could develop across the Lower to Middle Keys later this afternoon. The potential for a cloud line means that even though shower activity in the late morning as seen by KBYX is sparse, PoPs will remain near 20 percent. Overall, take precautions for heat and humidity for the next few days.

PREV DISCUSSION

Issued at 509 AM EDT Sun May 31 2026 Muggy conditions will continue today as the pattern will see little change. Breezes will remain light and variable, but may assume a southwesterly direction for a short period of time in the afternoon due to daytime heating. This would offer an opportunity for reverse cloudline development. With weak steering flow, around 3 knots, this could result in a prolonged period of rainfall where any cloudline develops. All of this depends on whether on not southwesterlies prevail long enough to make this happen, so this is something that will have to be monitored in real time.

Guidance still points to a deep trough digging into Florida by the middle of the week, and sending a frontal boundary down the peninsula. Generally, this means an uptick in rain chances, but one caveat is the potential for some Saharan dust potentially arriving at the same time. Guidance may be overdoing rain chances over the middle of the week, specifically on Wednesday and Thursday, and it will be something to keep in mind as the forecast evolves.

MARINE

Issued at 1020 AM EDT Sun May 31 2026 There are no watches, warnings, or advisories in effect for the Florida Keys local waters. From synopsis, weak high pressure across the area will support light to gentle southwesterly breezes over the next few days, becoming light and variable at times. Near normal rain and thunder chances also expected. A weak frontal boundary may stall near the Keys coastal waters by mid week, supporting an uptick in wind speeds as well as rain chances.

AVIATION

(12Z TAFS) Issued at 1020 AM EDT Sun May 31 2026 VFR conditions prevail at EYW and MTH for the upcoming TAF period. Occasional MVFR CIGs may be observed during the day. Chances for rain will remain near 20 percent. Near surface winds are expected to remain light and variable.

CLIMATE

On this day in 2024, the daily record warm low temperature of 84F was recorded in Key West. This is also tied for the warmest low temperature ever recorded in May. Temperature records for Key West date back to 1872.

PRELIMINARY POINT TEMPS/POPS

Key West 89 82 89 81 / 20 10 20 0 Marathon 88 81 88 81 / 20 10 20 0

KEY WATCHES/WARNINGS/ADVISORIES

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