Water temperature in Marathon
Sea surface temperature · updated today, Wednesday, October 28, at 7:53 pm (EDT)- Today
- 81.9–82.8 °F
- Air today
- 74 / 85 °F
- Tue 3
- 83.8 °F
- Wetsuit
- No wetsuit
Today the water in Marathon is 82.8 °F and ranges 81.9–82.8 °F through the day, with the air between 74 °F and 85 °F. It warms over the next few days: about 83.8 °F by Tuesday 3.
Measured by satellite
This is the temperature satellites measured yesterday in the water just below the surface, at the nearest point of sea to Marathon (0.3 mi away), from NASA's MUR analysis, which sees the water in 1 km detail. It isn't a forecast: the big figure above is what a model gives for right now. On sunny afternoons the top of the water can be a little warmer.
Satellite: NASA MUR (JPL MUR MEaSUREs, PO.DAAC), doi:10.5067/GHGMR-4FJ04. Sources and licenses
The water over the next few days
- Today
- Thu 29
- Fri 30
- Sat 31
- Sun 1
- Mon 2
- Tue 3
- Wed 4
- Thu 5
- Fri 6
Water over the last 60 days
Over these days it has dropped 7.2 °F (from August 29).
Over the next few weeks the water looks a bit above normal (+0.8 °F), according to ECMWF 46-day.
Daily average and its range (low and high). The dotted line is the forecast.
Water temperature by month vs. normal
The water off Marathon is warmer than normal for late October today (+2.3 °F).
- 74.6° 75°JanJ
- 74.5° 75°FebF
- 75.8° 76°MarM
- 78.1° 78°AprA
- 80.7° 81°MayM
- 83.5° 83°JunJ
- 85.1° 85°JulJ
- 85.8° 86°AugA
- 84.8° 85°SepS
- 82.6° 83°OctO
- 79.1° 79°NovN
- 76.7° 77°DecD
- Monthly normal
- Today
In Marathon the water is pleasant year-round: 74.5–85.8 °F on average, depending on the month.
The water is warmest in August (85.8 °F on average) and coldest in February (74.5 °F).
Monthly averages for 1991–2020 (NOAA OISST, from satellites and buoys; nearest data point 5.4 mi away). Right by the shore, the water can be a little colder or warmer. Sources and licenses
Water and air, day by day
| Day | Water | Air | Max wave |
|---|---|---|---|
| Today | 81.9–82.8 °F | 74 / 85 °F | 3.3 ft |
| Thu 29 | 82.6–83.5 °F | 75 / 84 °F | 2.4 ft |
| Fri 30 | 83.1–83.7 °F | 76 / 83 °F | 2.0 ft |
| Sat 31 | 83.3–83.7 °F | 78 / 83 °F | 1.7 ft |
| Sun 1 | 83.3–83.7 °F | 77 / 82 °F | 2.6 ft |
| Mon 2 | 83.3–83.8 °F | 76 / 82 °F | 3.2 ft |
| Tue 3 | 83.5–84.0 °F | 75 / 82 °F | 3.1 ft |
Which wetsuit to wear
| Water | Wetsuit | How it feels |
|---|---|---|
| < 52 °F | 6/5 mm with hood, booties and gloves | Very cold: full kit only |
| 52°–57 °F | 5/4 mm with booties | Cold: takes your breath away |
| 57°–63 °F | 4/3 mm | Cool |
| 63°–66 °F | 3/2 mm | Mild |
| 66°–72 °F | Shorty (springsuit) | Pleasant |
| 72°–75 °F | Rash guard or top | Very pleasant |
| > 75 °F | No wetsuit | Warm |
A rough guide: it depends on the wind, how long you stay in and each person.
Fish are cold-blooded: the water sets their activity. Sudden temperature changes usually put them off the bite; with steady water, activity is more regular.
Previous days
The water over the last 60 days.
| Day | Water | Low / high |
|---|---|---|
| Tue 27 | 81.9 °F | 81.7–82.2 °F |
| Mon 26 | 82.2 °F | 81.9–82.4 °F |
| Sun 25 | 82.2 °F | 81.9–82.4 °F |
| Sat 24 | 82.6 °F | 82.4–82.8 °F |
| Fri 23 | 82.8 °F | 82.6–82.9 °F |
| Thu 22 | 82.8 °F | 82.4–83.1 °F |
| Wed 21 | 82.6 °F | 82.2–82.9 °F |
Show all 60 days
| Day | Water | Low / high |
|---|---|---|
| Tue 20 | 83.7 °F | 83.3–84.0 °F |
| Mon 19 | 84.2 °F | 84.0–84.6 °F |
| Sun 18 | 85.3 °F | 84.7–86.0 °F |
| Sat 17 | 86.0 °F | 85.5–86.4 °F |
| Fri 16 | 85.6 °F | 85.5–86.0 °F |
| Thu 15 | 85.8 °F | 85.6–86.2 °F |
| Wed 14 | 86.4 °F | 86.2–86.5 °F |
| Tue 13 | 86.5 °F | 86.2–86.7 °F |
| Mon 12 | 86.5 °F | 86.2–86.7 °F |
| Sun 11 | 86.4 °F | 86.0–86.7 °F |
| Sat 10 | 86.4 °F | 86.2–86.5 °F |
| Fri 9 | 86.7 °F | 86.4–86.9 °F |
| Thu 8 | 86.9 °F | 86.5–87.1 °F |
| Wed 7 | 86.9 °F | 86.5–87.1 °F |
| Tue 6 | 86.2 °F | 85.8–86.7 °F |
| Mon 5 | 85.8 °F | 85.5–86.2 °F |
| Sun 4 | 85.6 °F | 85.3–85.8 °F |
| Sat 3 | 85.5 °F | 85.1–85.6 °F |
| Fri 2 | 85.1 °F | 84.7–85.5 °F |
| Thu 1 | 84.9 °F | 84.9–85.3 °F |
| Wed 30 | 85.5 °F | 85.3–85.8 °F |
| Tue 29 | 86.2 °F | 86.0–86.4 °F |
| Mon 28 | 86.4 °F | 86.0–86.7 °F |
| Sun 27 | 86.5 °F | 86.2–86.7 °F |
| Sat 26 | 86.7 °F | 86.4–87.1 °F |
| Fri 25 | 86.7 °F | 86.4–87.1 °F |
| Thu 24 | 86.5 °F | 86.2–86.9 °F |
| Wed 23 | 86.4 °F | 86.2–86.7 °F |
| Tue 22 | 87.1 °F | 86.9–87.4 °F |
| Mon 21 | 87.4 °F | 87.3–87.6 °F |
| Sun 20 | 87.8 °F | 87.4–88.0 °F |
| Sat 19 | 87.6 °F | 87.4–87.8 °F |
| Fri 18 | 87.6 °F | 87.3–88.0 °F |
| Thu 17 | 87.8 °F | 87.6–88.0 °F |
| Wed 16 | 88.2 °F | 87.8–88.5 °F |
| Tue 15 | 88.7 °F | 88.3–88.9 °F |
| Mon 14 | 88.7 °F | 88.2–89.2 °F |
| Sun 13 | 88.3 °F | 88.0–88.9 °F |
| Sat 12 | 88.2 °F | 87.8–88.5 °F |
| Fri 11 | 88.2 °F | 87.8–88.3 °F |
| Thu 10 | 88.5 °F | 88.3–88.7 °F |
| Wed 9 | 89.1 °F | 88.7–89.2 °F |
| Tue 8 | 89.2 °F | 88.9–89.8 °F |
| Mon 7 | 89.1 °F | 88.7–89.4 °F |
| Sun 6 | 89.2 °F | 88.9–89.4 °F |
| Sat 5 | 89.1 °F | 88.5–89.4 °F |
| Fri 4 | 89.1 °F | 88.5–89.4 °F |
| Thu 3 | 88.7 °F | 88.3–89.1 °F |
| Wed 2 | 88.5 °F | 87.8–89.1 °F |
| Tue 1 | 88.9 °F | 88.3–89.6 °F |
| Mon 31 | 88.5 °F | 88.0–89.1 °F |
| Sun 30 | 88.5 °F | 88.2–88.9 °F |
| Sat 29 | 89.1 °F | 88.9–89.6 °F |
It's the daily analysis from Météo-France / Copernicus Marine (satellites, buoys and model), not a buoy reading at this spot.
Questions about the water in MarathonQuestions
What's the water temperature today in Marathon?
82.8 °F; through the day it ranges 81.9–82.8 °F.
Will the water get warmer or colder?
It warms over the next few days: about 83.8 °F by Tuesday 3.
Which wetsuit do I need today?
With the water as it is today, no wetsuit (warm). It's a rough guide: it depends on the wind and each person.
How warm is the water in Marathon in October?
In October, the water in Marathon averages 82.6 °F (1991–2020). For a long swim: no wetsuit (warm).
How warm is the water in Marathon in August?
In August, the water in Marathon averages 85.8 °F (1991–2020), the warmest of the year. For a long swim: no wetsuit (warm).
When is the best time to swim in Marathon?
In Marathon the water is pleasant year-round: 74.5–85.8 °F on average, depending on the month. The water is warmest in August (85.8 °F on average) and coldest in February (74.5 °F).
Is the water warmer or colder than normal?
The water off Marathon is warmer than normal for late October today (+2.3 °F).
More about Marathon today
Water temperature near Marathon
- Big Pine Key 82.8 °F · 17 mi
- Layton 83.1 °F · 19 mi
- Cudjoe Key 81.3 °F · 26 mi
- Matecumbe 83.3 °F · 32 mi
- Big Coppitt Key 81.5 °F · 37 mi
- Plantation Key 81.5 °F · 38 mi
Only places with a different forecast: spots a few miles apart share the same model cell and wouldn't add anything.
Learn more
Sea surface temperature: Open-Meteo with Météo-France / Copernicus Marine, CC BY 4.0; grid point 2.2 mi away. Near the shore, in coves and estuaries, the water can be a little colder or warmer.
Forecast from Open-Meteo (CC BY 4.0) with models from ECMWF, NOAA, Météo-France, DWD, Copernicus Marine and CAMS. Updated at 7:53 pm (local time).
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