Hertasee
Why dive here
With 66+ marine species recorded in the area - including jellyfish lake - Hertasee offers some of Bornholm's richest reef diving. Water ranges 3-18°C, warmest July, August, September.
Hertasee, a landlocked lake on Bornholm, presents a unique freshwater dive. You'll find a silty bottom and limited visibility, but it’s a quiet spot for checking gear or practicing skills away from the sea’s swells. Keep an eye out for the local birdlife, Arctic Terns and Lesser Black-backed Gulls, above the surface. We'd suggest this site for training dives or divers seeking calm, controlled conditions.
Typical Hertasee Dive Profile
Illustrative profile based on site depth and type. Actual dive profiles vary - always follow your dive computer and training.
Safety Notes
Cold water this month (avg 14°C). Drysuit or thick wetsuit (7mm+) recommended.
Nearest Dive Centres to Hertasee
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Conditions
Ocean conditions, forecast and tides for Hertasee
Hertasee Ocean Conditions
Monthly averages for Hertasee, sourced from Open-Meteo marine data - nearest station: Open-Meteo marine grid (54.94, 13.85) (7km away)
October Averages
Sea Temperature
14°C
57°F · Range: 11.7–16.3°C
Air Temperature
12°C
53°F
Wind Speed
8.16 m/s
15.9 knots
Atmospheric Pressure
1013.3 hPa
Based on 4 years of monitoring data · Data sources: Open-Meteo marine data
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