INSTRUMENT / SEA TEMPERATURE
Piran Water Temperature
Updated Wed 13:04 (Europe/Ljubljana)
Slovenia · Forecast updated Nov 11, 2026, 13:04 UTC
Current Sea Temperature
18.2°C
64.8°F
Cool water
Valid Nov 11, 2026, 13:04 (Europe/Ljubljana). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
0.8°C above
The typical November average is 17.4°C (63.3°F) from the historical baseline.
Recent trend
Cooling by 0.9°C
Seven-day average: 18.7°C, versus 19.7°C in the prior seven days.
What to wear
Cool water
A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions or replace the snorkel forecast.
Typical Sea Temperature Over the Year
In the historical baseline for Piran, typical monthly averages range from about 11.4°C (52.5°F) in February to 26.2°C (79.2°F) in August.
Over the past 30 days, the average sea temperature in Piran has been 20.5°C.
Historical baseline (full year)
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Piran, calculated from hourly observations for 2023–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 11.2–13.1°C | 12.3°C / 54.1°F |
| February | 11.0–11.8°C | 11.4°C / 52.5°F |
| March | 11.3–12.8°C | 11.8°C / 53.2°F |
| April | 13.2–15.2°C | 14.2°C / 57.6°F |
| May | 17.1–18.7°C | 18.1°C / 64.6°F |
| June | 22.5–23.8°C | 23.3°C / 73.9°F |
| July | 25.8–26.5°C | 26.1°C / 79.0°F |
| August | 25.1–27.4°C | 26.2°C / 79.2°F |
| September | 24.0–24.2°C | 24.1°C / 75.4°F |
| October | 20.1–21.8°C | 20.7°C / 69.3°F |
| November | 16.7–18.1°C | 17.4°C / 63.3°F |
| December | 13.6–14.7°C | 14.0°C / 57.2°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (45.54, 13.54). 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 2023–2025 baseline. The range is the lowest and highest yearly monthly mean, not an hourly extreme.
Piran in January
Typical January water temperature near Piran is 12.3°C (54.1°F), with yearly monthly means from 11.2–13.1°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: December 14.0°C · February 11.4°C.
Explore Piran sea temperature in January, including swim comfort and month comparisons →
Piran in February
Typical February water temperature near Piran is 11.4°C (52.5°F), with yearly monthly means from 11.0–11.8°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: January 12.3°C · March 11.8°C.
Explore Piran sea temperature in February, including swim comfort and month comparisons →
Piran in March
Typical March water temperature near Piran is 11.8°C (53.2°F), with yearly monthly means from 11.3–12.8°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: February 11.4°C · April 14.2°C.
Explore Piran sea temperature in March, including swim comfort and month comparisons →
Piran in April
Typical April water temperature near Piran is 14.2°C (57.6°F), with yearly monthly means from 13.2–15.2°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: March 11.8°C · May 18.1°C.
Explore Piran sea temperature in April, including swim comfort and month comparisons →
Piran in May
Typical May water temperature near Piran is 18.1°C (64.6°F), with yearly monthly means from 17.1–18.7°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: April 14.2°C · June 23.3°C.
Explore Piran sea temperature in May, including swim comfort and month comparisons →
Piran in June
Typical June water temperature near Piran is 23.3°C (73.9°F), with yearly monthly means from 22.5–23.8°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: May 18.1°C · July 26.1°C.
Explore Piran sea temperature in June, including swim comfort and month comparisons →
Piran in July
Typical July water temperature near Piran is 26.1°C (79.0°F), with yearly monthly means from 25.8–26.5°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: June 23.3°C · August 26.2°C.
Explore Piran sea temperature in July, including swim comfort and month comparisons →
Piran in August
Typical August water temperature near Piran is 26.2°C (79.2°F), with yearly monthly means from 25.1–27.4°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: July 26.1°C · September 24.1°C.
Explore Piran sea temperature in August, including swim comfort and month comparisons →
Piran in September
Typical September water temperature near Piran is 24.1°C (75.4°F), with yearly monthly means from 24.0–24.2°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: August 26.2°C · October 20.7°C.
Explore Piran sea temperature in September, including swim comfort and month comparisons →
Piran in October
Typical October water temperature near Piran is 20.7°C (69.3°F), with yearly monthly means from 20.1–21.8°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: September 24.1°C · November 17.4°C.
Explore Piran sea temperature in October, including swim comfort and month comparisons →
Piran in November
Typical November water temperature near Piran is 17.4°C (63.3°F), with yearly monthly means from 16.7–18.1°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: October 20.7°C · December 14.0°C.
Explore Piran sea temperature in November, including swim comfort and month comparisons →
Piran in December
Typical December water temperature near Piran is 14.0°C (57.2°F), with yearly monthly means from 13.6–14.7°C.
Swimming and snorkeling: cold water. Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.
Adjacent months: November 17.4°C · January 12.3°C.
Explore Piran 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 | 21.5°C / 70.7°F | 24.6°C / 76.3°F | 28.5°C / 83.3°F |
| July | 24.7°C / 76.5°F | 26.8°C / 80.3°F | 28.9°C / 84.0°F |
| August | 26.5°C / 79.7°F | 27.8°C / 82.0°F | 29.6°C / 85.3°F |
| September | 23.4°C / 74.1°F | 25.6°C / 78.2°F | 27.9°C / 82.2°F |
| October | 19.9°C / 67.8°F | 22.0°C / 71.6°F | 23.6°C / 74.5°F |
| November | 17.7°C / 63.9°F | 18.7°C / 65.6°F | 19.9°C / 67.8°F |
Partial coverage: 6 calendar months with records. Profile calculated from 3934 hourly forecast records across 6 monthly periods. This is a growing archive, not a long-term climate normal.
About the water at Piran
Adriatic town with the Strunjan nature reserve's clear, sheltered shallows.
- Area
- Istria
Piran Water Temperature: Common Questions
What is the water temperature in Piran today?
The current sea surface temperature near Piran is 18.2°C (64.8°F). Over the last 30 days, the average has been 20.5°C.
When is the water warmest in Piran?
The water is typically warmest in August, at around 26.2°C (79.2°F) in the 2023–2025 historical baseline.
When is the water coldest in Piran?
The water is typically coldest in February, at around 11.4°C (52.5°F) in the same historical baseline. A wetsuit is usually recommended during this period.
Can you swim in Piran today?
The water is 18.2°C. It may feel cool, but a wetsuit or short swims can help.
Full Snorkeling Forecast
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Piran.
View Snorkel Forecast →