Is the Delaware Bay rough? What to expect on the crossing
Sometimes. NOAA's Coast Pilot calls Delaware Bay a large, open bay that is subject to confusing, and sometimes dangerous, sea and swell conditions because of a large fetch, strong currents and numerous shoals. The Cape May to Lewes ferry crosses 17 miles of it in about 85 minutes, and sails year-round.
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Bay · New Jersey and Delaware · Reputation among passengers: mixed: commonly reported as uncomfortable in the wrong conditions.
- Low
- Moderate
- High
- Very high
Roughness summarises typical reported conditions for this crossing, not a forecast for any given sailing.
Open bay, long fetch and strong currents
In the Nausea Index table of the 121 sea crossings we cover, the Delaware Bay is rated manageable, one of 81 in that band, with 40 rated higher. Full table: the roughest sea crossings, ranked.
Key facts
- The Delaware Bay is a bay, and passenger reports place it in the moderate roughness band.
- The mechanism behind that reputation: Open bay, long fetch and strong currents.
- Conditions are reported roughest in January, February, March and November.
- The calmest months are usually June, July and August.
Why does the Delaware Bay get rough?
The Coast Pilot says Delaware Bay is a large, open bay with confusing, and sometimes dangerous, sea and swell conditions due to a large fetch, strong currents and numerous shoals. It is shallow along its northeastern and southwestern sides, with extensive shoal areas close to the main channel, and has very few harbors of refuge between the entrance and the Chesapeake and Delaware Canal. Winter navigation is restricted by extratropical storms that ravage the mid-Atlantic coast. At NOAA's Delaware Bay buoy (44009), 26 nautical miles south-east of Cape May in the Atlantic, the daily maximum wave height averages 1.91 m in January and 1.15 m in July.
When is the Delaware Bay roughest?
The Coast Pilot says extratropical storms are most intense from fall through spring, and that variable winter weather runs from about November through March. At the Delaware Bay buoy the daily maximum wave height tops about 2.0 m on 31 to 38 percent of days from November to April, against 4 to 7 percent of days from June to August. The Coast Pilot adds that summer is the start of the hurricane season and that the threat of tropical storms and hurricanes continues in autumn.
| Roughest water in Jan | Roughest water in Feb | Roughest water in Mar | Roughest water in Apr | Roughest water in May | Roughest water in Jun | Roughest water in Jul | Roughest water in Aug | Roughest water in Sep | Roughest water in Oct | Roughest water in Nov | Roughest water in Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Rough | Rough | Rough | Mixed | Mixed | Calm | Calm | Calm | Mixed | Mixed | Rough | Mixed |
Typical seasonal pattern, not a forecast. Any month can deliver a calm crossing or a bad one. Check the marine forecast for your sailing date. Select a month to see every sea and ferry crossing ranked for it.
Where to be on board
Front to back
- Bow (front)Avoid
- MidshipBest
- Stern (aft)OK
The crossing: About 85 minutes
Roughest stretch: The open bay mouth, mid-crossing
Stay low and near the middle of the ship. The open middle of the crossing is where the bay's fetch and currents are felt most.
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The crossings that cross it
| Route | Typical duration | What to know |
|---|---|---|
| Cape May, New Jersey to Lewes, Delaware | About 85 minutes | Cape May-Lewes Ferry, 17 miles across the bay, with up to 14 sailings a day in peak season. |
| Lewes, Delaware to Cape May, New Jersey | About 85 minutes | The same ferry the other way, run by the Delaware River and Bay Authority. It sails year-round. |
What helps on this crossing
- Check the marine forecast and the sailing status before you drive to the terminal. The Coast Pilot strongly encourages vessels in the bay to monitor current weather conditions and forecast.
- Plan around winter. The Coast Pilot says extratropical storms restrict winter navigation, and the buoy record shows the roughest waves from November to March.
- Sit low and near the middle, watch the actual horizon line and put your phone away. The crossing is about 85 minutes.
For the full toolkit see the seasickness guide, or what to do once it has already started. For what the trials actually say about the oldest trick on that list, see the verdict on looking at the horizon. If the rocking follows you ashore afterwards, that is land sickness, which is normal, and it passes.
Frequently asked questions
Is Delaware Bay rough in July?
Usually not. At the Delaware Bay buoy, outside the bay mouth in the Atlantic, the daily maximum wave height averages 1.15 m in July against 1.91 m in January, and about 4 percent of July days top 2.0 m. The Coast Pilot says summer gales are rare but may be encountered during tropical cyclones or local thunderstorms.
Is Delaware Bay rough in January?
January is the roughest month at the buoy: the daily maximum wave height averages 1.91 m, and 38 percent of January days top 2.0 m. The Coast Pilot says winter navigation is restricted by extratropical storms and that variable winter weather runs from about November through March.
Is Delaware Bay rough in September?
It can be. About 28 percent of September days top 2.0 m at the buoy, against 4 to 7 percent from June to August. The Coast Pilot says the threat of tropical storms and hurricanes continues in autumn.
How long is the Cape May to Lewes ferry?
About 85 minutes, according to the operator, for a 17 mile crossing of the bay. The ferry sails year-round and is run by the Delaware River and Bay Authority.
Other crossings
Sources & further reading
- https://nauticalcharts.noaa.gov/publications/coast-pilot/files/cp3/CPB3_C06_WEB.pdf
- https://nauticalcharts.noaa.gov/publications/coast-pilot/files/cp3/CPB3_C03_WEB.pdf
- https://www.cmlf.com/about-the-ferry/
- https://www.cmlf.com/sailing-information/
- https://www.ndbc.noaa.gov/station_page.php?station=44009
Sea conditions described here are typical patterns drawn from published marine and operator information as of July 2026, not a forecast: conditions on any given sailing depend on the weather that day, and any month can deliver a calm crossing or a bad one. Route and operator names are trademarks of their respective owners; Dizzout is not affiliated with or endorsed by them. Seasickness sensitivity varies from person to person; this page is informational and not medical advice.