textproduct: Key West

KEY MESSAGES

- Gentle to moderate southeast to south breezes across the Florida Keys coastal waters, except light to gentle across the SE Gulf.

- Heat will be the primary weather concern through the rest of the week as indices may approach 108 to 110 degrees in the afternoon for portions of the island chain.

- Rounds of Saharan Air Layer will continue to stream across our area this week into next week, keeping rain and thunder chances slight, except chances across the SE Gulf.

FORECAST

The complex pattern remains in place across Florida and the eastern Gulf for the next few days. An upper level low will continue to slowly meander about the eastern Gulf sparking additional showers and thunderstorm coverage around it as it does so. The upper low has deepened with now closed off low pressure showing up at 850 mb and 700 mb. However, there is still no surface reflection. The National Hurricane Center (NHC) gives this system a 10% percent chance for tropical cyclone development over the next 48 hours and a 30% chance of tropical cyclone development over the next 7 days. Therefore, since the SE Gulf waters are the closest to the circulation, there remains a chance of showers and thunderstorms with a slight chance for the remainder of the Florida Keys and surrounding coastal waters. This upper level low is expected to lift northward as we head into early next week being replaced with ridging. Even with the ridging moving into place, moisture undulations will continue to propagate through the Keys resulting in slight chance of showers and thunderstorms. Outside of the rain chances, the dog days of summer are here with highs near 90 degrees and overnight lows in the lower 80s. Dew points are expected to remain in the mid to upper 70s resulting in heat values of 105 to 110 degrees. Therefore, make sure to take breaks and stay hydrated in the heat!

The Atlantic ridge will slowly gain more influence over the Keys over the coming days resulting in mainly southeast breezes. These breezes will largely peak in the evening and overnights and lull during the daytime hours.

MARINE

Issued at 443 AM EDT Sat Jul 18 2026 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, a closed upper level low will continue spinning just off the West Coast of Florida today. This low is caught in between a split ridge with one piece of the ridge across the western North Atlantic and the other across the western Gulf. The ridge over the Atlantic will begin to slowly influence the Keys coastal waters over the next several days. Therefore, expect mainly southeasterly breezes to continue into at least early next week. Breezes will tend to surge overnight, then lull in the afternoon.

AVIATION

(06Z TAFS) Issued at 443 AM EDT Sat Jul 18 2026 VFR conditions are expected to persist at both EYW and MTH terminals through the TAF period. Near surface winds will remain southeast to south through the period. There remains the risk for an isolated shower or thunderstorm throughout the period. Confidence remains low on timing and placement, therefore, VCSH was not included at this time.

CLIMATE

On this day on 2023, the daily record warm low temperature of 87F was recorded in Key West. This is also tied for the warmest low temperature ever recorded in July for the Key West area. Temperature records for Key West date back to 1872.

Also, on this day in 2023, the daily record warm low temperature of 87F was recorded in Marathon. This is also the warmest low temperature ever recorded in July and ties the warmest low temperature ever recorded in the Marathon area. Temperature records for Marathon date back to 1951.

PRELIMINARY POINT TEMPS/POPS

Key West 90 83 90 83 / 20 20 20 20 Marathon 90 82 91 82 / 20 20 20 20

KEY WATCHES/WARNINGS/ADVISORIES

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