Sunny, high near 84°. No real rain risk. All-day beach window.
forecastRain OutlookOpen-Meteo
tap an hourTop rain chance is just 5% — pack the sunscreen, not the umbrella.
Tide
0.3 ft · falling ↘
Next low tide
12:24 PM 0.2 ft
T−…
1.9 ft of drop from the 7:54 AM high; the wet sand is widest from about 11:24 AM.
Wind
14 mph
from the ENE
UV Index
High
reapply every 80 min
Time to Burn
UV 6 · incl. sand glarefor unprotected fair skin (burns easily, tans a little). SPF 30+, reapply every 2 hours and after every swim.
Strongest 12 PM to 4 PM · peaks at UV 7
An estimate from the standard erythemal dose model, not a medical limit. Darker skin burns more slowly than this, people vary either way, and sunscreen only helps if you use enough of it and reapply.
Rip Current Riskestimated
todayCalm pattern today. Currents can still surprise — keep kids within reach.
Caught in one? Don’t fight it. Swim parallel to the beach until you’re free, then angle back in.
Beach Flag
Green Flag
calm, swim easy
estimated · trust the lifeguard
Red Tide
Checking…
asking FWC
Water Quality
bacteria testingWater here is sampled by the Florida Healthy Beaches Program at the Sunset Park station (2.8 km from the beach centre). We do not restate the result, because the state publishes it only on its own page and a stale copy here could be wrong about today.
Today’s official resultSource: Florida Department of Health
Sargassum WatchNOAA satellite
seaweed outlookLatest 7-day NOAA satellite composite detects moderate sargassum offshore. Some may drift onto the beach. Offshore satellite estimate only — on-the-ground conditions may differ.
Water by Monthtypical
avg 2021–2024Warmest around July (89°), coolest around January (75°).
surf’s up (gently)
Tides are NOAA predictions (Marathon station 8724580); temps, wind, UV, waves and water temp are live from Open-Meteo; rip current risk from the NWS surf-zone forecast; red tide from FWC sampling. Flag status is estimated from wave height and wind, so always trust the lifeguard’s actual flag over this app.
The air is 77°F, feeling like 83°F, with breezy 11 mph winds from the NE. The UV index reaches 7 (high), strongest from 1 PM to 4 PM.
The week ahead at Marathon, day by day: the sky, the high, the strongest wind and the biggest waves, the UV peak and the daytime chance of rain. The calmest day for a swim looks like Wed Nov 4.
| Day | Sky | High | Wind | Waves | UV | Rain |
|---|---|---|---|---|---|---|
| Today | Mostly sunny | 84°F | 14 mph | — | 7 | 5% |
| Fri Oct 30 | Cloudy | 83°F | 14 mph | — | 7 | 18% |
| Sat Oct 31 | Cloudy | 79°F | 14 mph | — | 6 | 16% |
| Sun Nov 1 | Thunderstorms | 79°F | 16 mph | — | 5 | 41% |
| Mon Nov 2 | Thunderstorms | 79°F | 15 mph | — | 6 | 28% |
| Tue Nov 3 | Drizzle | 79°F | 13 mph | — | 6 | 7% |
| Wed Nov 4 | Cloudy | 80°F | 8 mph | — | 6 | 7% |
High and low tides for the next 7 days, from NOAA’s predictions for tide station 8724580. Heights are in feet above the average low tide. The shell window is the last hour and a quarter of the ebb and the first three-quarters of the flood around the day’s lowest daylight low, when the most sand is bare; the lowest low of the week is marked.
| Day | Tide 1 | Tide 2 | Tide 3 | Tide 4 | Shell window |
|---|---|---|---|---|---|
| Today | Low 6:43 AM 0.0 | High 1:39 PM 1.4 | Low 5:43 PM 0.9 | — | 4:28 PM–6:28 PM |
| Fri Oct 30 | High 12:41 AM 2.5 | Low 7:43 AM 0.1 | High 2:38 PM 1.3 | Low 6:32 PM 0.9 | 6:28 AM–8:28 AM · best |
| Sat Oct 31 | High 1:39 AM 2.4 | Low 8:51 AM 0.3 | High 3:46 PM 1.3 | Low 7:37 PM 1.0 | 7:36 AM–9:36 AM |
| Sun Nov 1 | High 1:49 AM 2.2 | Low 9:02 AM 0.4 | High 3:59 PM 1.4 | Low 8:09 PM 1.0 | 7:47 AM–9:47 AM |
| Mon Nov 2 | High 3:13 AM 2.1 | Low 10:08 AM 0.6 | High 5:03 PM 1.5 | Low 9:47 PM 1.0 | 8:53 AM–10:53 AM |
| Tue Nov 3 | High 4:43 AM 2.0 | Low 11:05 AM 0.7 | High 5:52 PM 1.7 | Low 11:10 PM 0.8 | 9:50 AM–11:50 AM |
| Wed Nov 4 | High 6:03 AM 2.0 | Low 11:52 AM 0.8 | High 6:33 PM 1.9 | — | 10:37 AM–12:37 PM |
The average sea temperature at Marathon for each month (2021–2024). The water is warmest in July (89°F) and coolest in January (75°F). It averages 74°F or warmer, comfortable for most swimmers, in every month.
| Month | Water °F | Water °C | For swimming |
|---|---|---|---|
| January | 75°F | 24°C | Comfortable |
| February | 75°F | 24°C | Comfortable |
| March | 79°F | 26°C | Comfortable |
| April | 79°F | 26°C | Comfortable |
| May | 84°F | 29°C | Warm |
| June | 86°F | 30°C | Very warm |
| July | 89°F | 31°C | Very warm |
| August | 88°F | 31°C | Very warm |
| September | 88°F | 31°C | Very warm |
| October (now) | 84°F | 29°C | Warm |
| November | 81°F | 27°C | Warm |
| December | 77°F | 25°C | Comfortable |
Rip currents. If a current pulls you away from shore, don’t fight it: swim parallel to the beach until you are out of it, then swim back in. If you can’t, float and wave for help.
Sun. The UV index peaks at 7 today, when unprotected fair skin burns in about 22 minutes. Wear SPF 30 or higher, reapply every two hours and after swimming, and find shade in the middle of the day.
Red tide. Florida's state sampling (FWC) has flagged nothing near Marathon this week. Red tide can make you cough and sting your eyes near the water.
Seaweed. The NOAA satellite shows moderate sargassum offshore.
Water quality. Water at Marathon is sampled by the Florida Healthy Beaches Program at the Sunset Park station. Official sampling results →
Dogs. Dogs are allowed right now, on a leash.
Swim near a lifeguard when one is on duty, and follow the beach flags and posted signs. The Marathon rules page covers dogs, alcohol, fires and more.
Under 1 ft is calm, good for small children and floating. 1–2 ft is small, fine for most swimmers. 2–4 ft is moderate: fun for bodyboarding, harder for weak swimmers. 4–6 ft is rough, and over 6 ft is dangerous for swimming.
Under 8 mph is light and pleasant. 8–15 mph is breezy, good for kites and cooler on a hot day. 15–25 mph blows sand and whips up the water. Over 25 mph most people pack up. Today at Marathon it’s breezy.
0–2 is low, 3–5 moderate, 6–7 high, 8–10 very high and 11 or more extreme. At 8 or more, fair skin can burn in under 20 minutes. The UV index is highest around midday even when it is cloudy.
Under 60°F is cold and most people want a wetsuit. 68–73°F is cool but swimmable. 74–79°F feels comfortable, and 80°F or more feels warm.
High tide is at 1:39 PM, and low tide is at 6:43 AM and 5:43 PM. Times are NOAA predictions.
The UV index peaks at 7 (high). At that peak, unprotected fair skin burns in about 22 minutes. Wear SPF 30 or higher, reapply every two hours and after swimming, and find shade in the middle of the day.
Florida's state sampling (FWC) has flagged nothing near Marathon this week.
The NOAA satellite shows moderate sargassum offshore.
Highs run 79–84°F over the next 7 days. No day has a strong chance of rain. The calmest day for a swim looks like Wed Nov 4.
The water at Marathon averages about 84°F (29°C) in October.
July is the warmest month, averaging 89°F. January is the coolest, at 75°F.
The water averages 74°F or warmer from January to December. July is the warmest, at 89°F.
The usual water temperature in October at the nearest beaches. Tap one for its live conditions.
| Sombrero Beach conditions | 3 mi | 83°F |
|---|---|---|
| Duck Key conditions | 10 mi | 83°F |
| Bahia Honda conditions | 15 mi | 84°F |
| Long Key conditions | 16 mi | 84°F |
| Big Pine Key conditions | 19 mi | 84°F |
| Lower Keys conditions | 26 mi | 83°F |
More for Marathon: parking · sunset time tonight · things to do · US water temperatures today →