Lock 21
Lock 21 offers a thrilling and one-of-a-kind dive experience where you can immerse yourself in the history of a 19th-century submerged Victorian canal lock on the majestic St. Lawrence River. With its strong currents, this dive is best suited for experienced divers who are up for a challenge.
While the dive itself is primarily focused on its historical significance, you may also have the opportunity to encounter various species of fish such as bass, trout, and catfish as they gracefully navigate the waters surrounding the lock.
For more detailed information about Lock 21, including dive guides and resources, please visit the Save Ontario Shipwrecks website. Take a leap into the past and discover the hidden wonders of this extraordinary dive site.
While the dive itself is primarily focused on its historical significance, you may also have the opportunity to encounter various species of fish such as bass, trout, and catfish as they gracefully navigate the waters surrounding the lock.
For more detailed information about Lock 21, including dive guides and resources, please visit the Save Ontario Shipwrecks website. Take a leap into the past and discover the hidden wonders of this extraordinary dive site.
Diving Conditions Score for Lock 21
6.1
Above AverageDecent conditions, proceed with caution.
The score is based on a calculation of the current weather and sea conditions.
Dive Site Overview for Lock 21
Depth
16m
Visibility
4m
Experience Level
advanced
expert
Weather Conditions for Lock 21
Wave Height
1m
Wind Speed
10 m/s
Water Temp
18°C
Visibility
15km
Cloud Cover
57.5%
Wave Period
8s
Air Temperature
20°C
Precipitation
0 mm
Detailed 7-Day Diving Forecast for Lock 21
Alpha
Dive Score Chart for Lock 21
Best time to dive: 6:00 with score 7.113333333333333/10. Water conditions: Waves 1m, Wind 10 m/s.Best night dive time: 0:00 with score 6.613333333333333/10.
Chart showing hourly dive conditions including wave height, wind speed, water temperature, and visibility throughout the day.
Sunrise at Lock 21: 06:00
Sunset at Lock 21: 18:00
Optimal diving conditions at Lock 21 are affected by daylight hours. Sunrise occurs at 06:00 and sunset at 18:00, which impacts visibility and water temperature for scuba diving and snorkeling.
Best Overall
6:00Score: 7.1/10
Waves: 1m (8s), Wind: 10 m/s
Best Night
0:00Score: 6.6/10
Waves: 1m, Wind: 10 m/s
Seasonal Analysis for Lock 21Alpha
Historical patterns and best seasons for diving at Lock 21
The dive score combines all factors to rate overall diving conditions throughout the year. Higher scores indicate better diving conditions.
Monthly Dive Score Analysis - Seasonal Diving Conditions
Higher values indicate better diving conditions
Seasonal DiveScore Chart
This chart displays monthly diveScore data throughout the year, showing seasonal patterns. The data is presented as a bar chart with an overlaid line graph.Dive scores range from 1 to 10, with 10 being optimal conditions.
Higher values indicate better diving conditions
Best Season for Lock 21
Winter
Avg. Score: 9.9/10
Winter offers the best overall diving conditions with calmer seas and better visibility, despite cooler temperatures.
Best Months for Lock 21
January
Score: 10.0
February
Score: 9.9
December
Score: 9.8
Ideal Conditions for Lock 21
Water Temp
24.5°C / 76.1°F
June
Visibility
20.1m / 65.9ft
October
Wave Height
0.2m / 0.7ft
January
Wave Period
8.0s
January
Seasonal Insights for Lock 21
Lock 21 shows typical northern hemisphere patterns with June being the warmest month (24.5°C) and December the coldest (20.5°C). The calmest conditions typically occur in January with average wave heights of 0.2m and wave periods of 8.0s. The most comfortable wave conditions are in January with a low wave steepness ratio, creating gentler swells. January offers the longest wave periods (8.0s), creating more comfortable and predictable conditions for boat entries and exits. Ocean currents are slowest in January (0.5m/s) and strongest in January (0.5m/s). January is usually the driest month with 0.0mm of precipitation. For beginners, the best time to visit would be during January to March, when ocean conditions are calmer with long-period waves and currents are typically weaker. Experienced divers might enjoy the challenges and potentially better visibility during the shoulder seasons, with moderate currents that can improve marine life encounters.
Last updated: 1 min. ago - Jun 22, 2026
Note: This dive site is not a verified dive site. Please dive with caution. This dive site might have incorrect information by the community.
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