As of 3:46 AM EST, Sunday, Nov 15: Snorkeling the reef off Key West tomorrow: Marginal. Wind NNE 8 kt, gusts 11 at the Key West harbor gauge. Seas up to 2 ft in Hawk Channel. No small craft advisory. Water 80.2°F. Sources: NWS Key West, NOAA.
Bumpy ride and cloudier water. Trips may still run. Ask your captain about a sheltered site.
Why: forecast wind 15 kt.
Too rough for the reef? See one up close, free.
Our Key West shop is full of living reef tanks: corals, fish and Florida Keys invertebrates you can stand nose to glass with, and nobody gets seasick. Open today 12 PM to 5 PM.
Get directions Call (305) 850-9949
The Underwater Gardener, in the Overseas Market plaza. Wed–Sat 11 AM–6 PM, Sun 12–5 PM, closed Mon and Tue.
Next few days
From the NWS Hawk Channel forecast only. Live wind is added on the day.
The details
NWS marine forecast, Key West reef
Overnight: North to northeast winds near 15 knots early, decreasing to 10 to 15 knots. Seas 1 to 2 feet, except 3 to 4 feet, occasionally to 5 feet west of Cosgrove Shoal Light. Nearshore waters a moderate chop, becoming a light to moderate chop.
Sunday: North to northeast winds 10 to 15 knots. Seas 1 to 2 feet, except 2 to 3 feet west of Cosgrove Shoal Light. Nearshore waters a light to moderate chop.
Sunday Night: Northeast to east winds 15 to 20 knots. Seas 2 to 3 feet. Nearshore waters choppy.
Monday: Northeast to east winds 15 to 20 knots, increasing to 20 to 25 knots. Seas 2 to 4 feet, occasionally to 5 feet. Nearshore waters choppy, becoming very rough.
Zone GMZ044, Hawk Channel from the west end of Seven Mile Bridge to Halfmoon Shoal out to the reef. NWS source
Tides at Key West
- Low Sun 7:47 AM 0.5 ft
- High Sun 2:27 PM 1.3 ft
- Low Sun 6:28 PM 1.1 ft
- High Mon 1:28 AM 1.9 ft
- Low Mon 8:42 AM 0.6 ft
NOAA station 8724580, Key West. Heights above mean lower low water.
Sun and UV
Sunrise 6:43 AM · Sunset 5:40 PM
UV: EPA hourly forecast for 33040.
How we make the call
A weather app tells you whether it will rain. It does not tell you whether the reef trip you booked is going to be any fun. This page does, and shows its work. It reads the National Weather Service marine forecast for the water between Key West and the reef, the wind gauge on Sand Key Light (the lighthouse on the reef, about 7 miles off Key West), the offshore wave buoy at Satan Shoal, and NOAA’s Key West tide station. It refreshes every 10 minutes.
- Stay In when the Weather Service has a small craft advisory or a marine warning up, when the forecast calls for 20 knots of wind or more, when Sand Key reads 20 knots two readings in a row, when forecast seas reach 4 feet, or when thunderstorms are likely.
- Marginal when wind runs 15 to 19 knots, gusts reach 20, seas reach 3 feet, the forecast says small craft should exercise caution, or there is a chance of storms. Boats often still go. The ride is bumpy, the water is cloudier, and captains move to calmer sites.
- Go when none of that is true. Under 10 knots with seas of a foot or less, we call it a great day.
The 4-foot line is ours, not the Weather Service’s. Their small craft advisory for seas does not start until 7 feet, and nobody enjoys snorkeling in 6-foot seas. If the data feeds go down, the page says so and makes no call. It never guesses Go.
Your captain makes the real decision. This is our read of public NOAA data, not a trip cancellation. If your trip gets canceled for weather, most Key West operators refund or rebook you. Check your booking terms.
Questions we get at the counter
Is it too rough to snorkel in Key West today?
The call at the top of this page answers that, with the reason under it. Wind matters more than anything else. Under about 15 knots, the reef is usually pleasant. Between 15 and 20, trips run but the ride out is rough and visibility drops. At 20 knots and up, the Weather Service issues a small craft advisory and most reef trips stay at the dock.
What is a small craft advisory?
It is a Weather Service alert for sustained wind of 20 to 33 knots, or seas of 7 feet or more in the Key West office’s waters. There is no legal definition of a small craft. It is a warning that the water is rough for most recreational boats, and that includes snorkel boats.
Which marine forecast covers the Key West reef?
Zone GMZ044: Hawk Channel from the west end of Seven Mile Bridge to Halfmoon Shoal, out to the reef. That is the water you cross to reach Sand Key and the other reefs off Key West. A lot of people pull up the Gulf forecast instead, which covers the back side of the island and can read very differently.
Why can the wind look bad when the seas look fine?
Direction. The reef lies south of Key West, and a north wind blows off the islands, so it has little open water to build waves before it reaches the reef. A strong north wind can still leave Hawk Channel fairly flat. A south or east wind of the same speed has miles of open water to work with. We still use the wind speed in the call, because a 20-knot wind makes for a hard day on a boat from any direction.
What is the water temperature in Key West today?
The water tile above shows the latest reading from NOAA’s Key West tide gauge, and the offshore buoy when it reports. Summer water runs in the mid to upper 80s. Winter cold fronts can drop it into the low 70s for a few days. Most people are comfortable in a rash guard down to the high 70s. Below that, a thin wetsuit makes a long swim a lot nicer.
How far is the reef from Key West?
Sand Key, one of the most popular reef sites, is about 7 miles off Key West. The reef runs the length of the Keys, and on rough days captains look for sites with some shelter from the wind.
What can I do in Key West when it is too rough to snorkel?
Come see a reef up close at our shop. We keep living reef tanks full of corals, fish and invertebrates from the Florida Keys and around the world, and you can stand nose to glass with animals you would only glimpse from the surface. It is free to walk in. We are in the Overseas Market plaza. Get directions.
Where the numbers come from
- National Weather Service Key West: marine forecast and active alerts for zone GMZ044 (Hawk Channel) and GMZ054 (Straits of Florida).
- NOAA National Data Buoy Center: Sand Key Light station SANF1 for wind, buoy 42095 at Satan Shoal for wave height and water temperature.
- NOAA Tides and Currents: Key West station 8724580 for water temperature, backup wind and tide predictions.
- EPA: hourly UV forecast for Key West, 33040.
Times are Key West time. Sand Key’s wind gauge sits about 49 feet above the water, so it reads a little higher than the wind you feel on deck.