INSTRUMENT / SEA TEMPERATURE
Key Largo Water Temperature
Updated Mon 13:51 (America/New_York)
USA · Forecast updated Nov 9, 2026, 13:51 UTC
Current Sea Temperature
27.5°C
81.5°F
Warm water
Valid Nov 9, 2026, 13:51 (America/New_York). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
1.8°C above
The typical November average is 25.7°C (78.3°F) from the historical baseline.
Recent trend
Holding fairly steady
Seven-day average: 27.6°C, versus 27.6°C in the prior seven days.
What to wear
Warm water
Most people are comfortable in swimwear or a light rash guard.
Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions or replace the snorkel forecast.
Key Largo is the northern gateway to the Florida Keys reef tract, including John Pennekamp Coral Reef State Park. Use this page for water temperature, then check the live forecast for wind, waves and the day's snorkel score. Temperature alone is not a safety rating.
Typical Sea Temperature Over the Year
In the historical baseline for Key Largo, typical monthly averages range from about 22.2°C (72.0°F) in January to 31.4°C (88.5°F) in August.
Over the past 30 days, the average sea temperature in Key Largo has been 28.3°C.
Historical baseline (full year)
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Key Largo, calculated from hourly observations for 2022–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 21.2–22.8°C | 22.2°C / 72.0°F |
| February | 21.9–25.2°C | 23.6°C / 74.5°F |
| March | 24.2–25.8°C | 25.2°C / 77.4°F |
| April | 25.5–27.3°C | 26.2°C / 79.2°F |
| May | 28.5–29.6°C | 28.9°C / 84.0°F |
| June | 29.6–30.7°C | 30.1°C / 86.2°F |
| July | 30.2–32.4°C | 31.2°C / 88.2°F |
| August | 30.8–31.8°C | 31.4°C / 88.5°F |
| September | 30.4–30.9°C | 30.7°C / 87.3°F |
| October | 28.0–28.4°C | 28.3°C / 82.9°F |
| November | 25.5–25.9°C | 25.7°C / 78.3°F |
| December | 23.1–24.8°C | 23.8°C / 74.8°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (25.13, -80.46). Each month is the mean of yearly monthly means; the range is the lowest and highest of those yearly monthly means. Open-Meteo methodology.
Water temperature by month
Each month uses the 2022–2025 baseline. The range is the lowest and highest yearly monthly mean, not an hourly extreme.
Key Largo in January
Typical January water temperature near Key Largo is 22.2°C (72.0°F), with yearly monthly means from 21.2–22.8°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: December 23.8°C · February 23.6°C.
Explore Key Largo sea temperature in January, including swim comfort and month comparisons →
Key Largo in February
Typical February water temperature near Key Largo is 23.6°C (74.5°F), with yearly monthly means from 21.9–25.2°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: January 22.2°C · March 25.2°C.
Explore Key Largo sea temperature in February, including swim comfort and month comparisons →
Key Largo in March
Typical March water temperature near Key Largo is 25.2°C (77.4°F), with yearly monthly means from 24.2–25.8°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: February 23.6°C · April 26.2°C.
Explore Key Largo sea temperature in March, including swim comfort and month comparisons →
Key Largo in April
Typical April water temperature near Key Largo is 26.2°C (79.2°F), with yearly monthly means from 25.5–27.3°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: March 25.2°C · May 28.9°C.
Explore Key Largo sea temperature in April, including swim comfort and month comparisons →
Key Largo in May
Typical May water temperature near Key Largo is 28.9°C (84.0°F), with yearly monthly means from 28.5–29.6°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: April 26.2°C · June 30.1°C.
Explore Key Largo sea temperature in May, including swim comfort and month comparisons →
Key Largo in June
Typical June water temperature near Key Largo is 30.1°C (86.2°F), with yearly monthly means from 29.6–30.7°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: May 28.9°C · July 31.2°C.
Explore Key Largo sea temperature in June, including swim comfort and month comparisons →
Key Largo in July
Typical July water temperature near Key Largo is 31.2°C (88.2°F), with yearly monthly means from 30.2–32.4°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: June 30.1°C · August 31.4°C.
Explore Key Largo sea temperature in July, including swim comfort and month comparisons →
Key Largo in August
Typical August water temperature near Key Largo is 31.4°C (88.5°F), with yearly monthly means from 30.8–31.8°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: July 31.2°C · September 30.7°C.
Explore Key Largo sea temperature in August, including swim comfort and month comparisons →
Key Largo in September
Typical September water temperature near Key Largo is 30.7°C (87.3°F), with yearly monthly means from 30.4–30.9°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: August 31.4°C · October 28.3°C.
Explore Key Largo sea temperature in September, including swim comfort and month comparisons →
Key Largo in October
Typical October water temperature near Key Largo is 28.3°C (82.9°F), with yearly monthly means from 28.0–28.4°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: September 30.7°C · November 25.7°C.
Explore Key Largo sea temperature in October, including swim comfort and month comparisons →
Key Largo in November
Typical November water temperature near Key Largo is 25.7°C (78.3°F), with yearly monthly means from 25.5–25.9°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: October 28.3°C · December 23.8°C.
Explore Key Largo sea temperature in November, including swim comfort and month comparisons →
Key Largo in December
Typical December water temperature near Key Largo is 23.8°C (74.8°F), with yearly monthly means from 23.1–24.8°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: November 25.7°C · January 22.2°C.
Explore Key Largo sea temperature in December, including swim comfort and month comparisons →
Forecast archive (growing)
These values come from hourly forecasts SnorkelForecast has stored. They cover only months with records and do not replace the historical baseline.
| Month | Min | Average | Max |
|---|---|---|---|
| June | 28.5°C / 83.3°F | 30.5°C / 86.9°F | 31.9°C / 89.4°F |
| July | 30.6°C / 87.1°F | 31.3°C / 88.3°F | 32.1°C / 89.8°F |
| August | 30.8°C / 87.4°F | 31.7°C / 89.1°F | 32.6°C / 90.7°F |
| September | 29.5°C / 85.1°F | 30.9°C / 87.5°F | 32.0°C / 89.6°F |
| October | 26.7°C / 80.1°F | 28.9°C / 84.0°F | 30.3°C / 86.5°F |
| November | 27.0°C / 80.6°F | 27.6°C / 81.7°F | 28.1°C / 82.6°F |
Partial coverage: 6 calendar months with records. Profile calculated from 3886 hourly forecast records across 6 monthly periods. This is a growing archive, not a long-term climate normal.
About the water at Key Largo
Gateway to John Pennekamp park and the shallow Florida Keys reef tract.
- Area
- Florida
Key Largo Water Temperature: Common Questions
What is the water temperature in Key Largo today?
The current sea surface temperature near Key Largo is 27.5°C (81.5°F). Over the last 30 days, the average has been 28.3°C.
When is the water warmest in Key Largo?
The water is typically warmest in August, at around 31.4°C (88.5°F) in the 2022–2025 historical baseline.
When is the water coldest in Key Largo?
The water is typically coldest in January, at around 22.2°C (72.0°F) in the same historical baseline.
Can you swim in Key Largo today?
At 27.5°C, the water is usually comfortable for swimming and snorkeling.
Full Snorkeling Forecast
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Key Largo.
View Snorkel Forecast →