April 11, 2022

Matt Weidert

BVI Weather and Marine Forecast Resources for Sailing

During my first bareboat trip to the BVIs many years ago, I didn’t pay much attention to the weather forecast. Big mistake.

Everything was fine and we enjoyed the steady 10-15 knot easterly trades and an occasional isolated thunderstorm - typical British Virgin Islands weather. But - what if we were caught in Cane Garden Bay when a northerly ground swell picked up at 2:00am?

It could have been dangerous and at a minimum quite uncomfortable for the crew.

As I’ve become more experienced (and wiser with age) I watch the BVI weather like a hawk before and during our sailing trips. I’ve even figured out how to use an Iridium GO! and download Predict Wind forecast data over satellite for some charter destinations.

The good news for the BVIs is that with decent cell phone coverage throughout the sailing grounds, you can get everything you need from the palm of your hand.

In this post, I’ve collected all the info you need to plan for and monitor the BVI weather for your next boat trip. And, given the proximity of the BVI neighbors - USVI and Spanish Virgin Islands - this weather info will be just as good for those sailing destinations as well.

Here’s what I’ll cover:

British Virgin Islands weather information links
BVI Weather features to watch out for
What is the weather like in the British Virgin

British Virgin Islands weather information links

NOAA marine forecast

This is the official NOAA marine forecast for the Virgin Islands.

Once the map loads, click on the area you will be sailing in. Precipitation is likely to be similar between the different forecast regions, but sea height will have notable differences: sailing within the protection of the islands (AMZ725) you can expect a lesser sea state (vs AMZ715).

I like to follow it for a couple weeks before my trip, and then I check it daily. It covers 5-6 days and provides you information on 5 areas.

Synopsis - general overview of the weather features affecting the area
Wind speed (here’s a link to the Beaufort Scale if you need to freshen up on your terminology)
Sea state - wave height and period
Chance of precipitation
Northerly ground swells (see below)

Approaching an isolated thunderstorm and preparing to adjust our sails

Difference between isolated and scattered thunderstorms

You’ll often see the terms isolated or scattered thunderstorms in the marine forecast (instead of the % chance of precipitation common with many weather forecasts. Here’s the difference

Isolated thunderstorms (or showers): expected to cover 1/8th of the forecast area
Scattered thunderstorms: expected to cover 1/8 to 1/2 of the coverage area

Windy app

I like the windy app to visualize the forecast. It also works on your desktop and is free!

In addition to wind speed/direction, you can see wave, swell, cloud cover, and more.

For a more chart-based view, some cruisers like Windguru.

Radio and VHF

If you don't have internet access while underway, you can pick up the marine forecast at the following channels:

Radio: ZBV 780 AM
- Daily marine forecast:
  - M-F: 8:05am
  - Sat: 7:30am
  - Sun: 9:45am
- Weather updates are also broadcast throughout the day. You can check the schedule here.
VHF: The NOAA forecast is broadcast nonstop on WX3 and WX4.

Radar Scope shows your location and bearing relative to squalls and lightning strikes

RadarScope App

If you are sailing where you'll have regular access to cell service, consider installing the RadarScope app on your phone. In BVI, you'll get coverage from the TJUA radar in San Juan, Puerto Rico. There is generally cell phone service throughout BVI.

You'll get hi-resolution doppler radar so you can keep track of thunderstorms. I like how you can see your location and heading on the map. Gives you a better picture of where the storms are in relation to your sailing yacht.

10-day forecast: Wunderground

For a standard 10-day forecast, my go to is Wunderground. This link is for Road Town, Tortola.

Ground swells are well forecasted by NOAA

BVI weather features to watch out for

Northerly ground swells

This one can catch novices by surprise. Ground swells can affect northerly exposed anchorages, making them uncomfortable and potentially dangerous.

From Nov-Apr, strong storms in the far away North Atlantic produce these swells that then travel all the way down to the British Virgin Islands.

The result can be extremely rolly anchorages and even breaking waves on the shore. Boats have been known to be thrown ashore from ground swells, so take caution.

The good news is they are extremely well forecasted, so check that forecast often. You can also see the Cane Garden Bay surf report.

To monitor real time data, check out this buoy plot, which is a located a few hundred miles offshore to the north.

Notable BVI destinations affected by ground swells:

Cane Garden Bay: if any ground swell is forecasted, we avoid CGB. Try Diamond Cay or other Jost Van Dyke anchorages instead
The Baths: while not an overnight destination, the mooring field will be quite rolly and swimming ashore from the dingy tie-off can be very dangerous. Many times the swell will cause red flag conditions, and using the NPS mooring balls is prohibited. You can check flag conditions on the National Parks Trust facebook page. If you don’t have schedule flexibility and need to fit in a visit to the Baths, you have two options
- Take a taxi from North Sound, such as Leverick Bay
- Grab a slip at Virgin Gorda Yacht Harbour and get a taxi
Cooper Island: swells can wrap around into the mooring field, again, making this one unpleasant

I was backwinded during this lunch stop at Muskmelon Bay | Easterly trade winds, but yacht is facing west

Backwinding while anchored

Backwinding is possible at some popular BVI anchorages. Make sure you understand what it means and how to plan for it. You can see at example above at Muskmelon Bay at Guana Island.

Strong winds (~15+ knots) blow, in this case from the easterly trade winds in the BVIs
When the wind reaches this speed and blows over tall terrain (like many of the BVI islands), it doesn't just blow straight over. A vortex is created and creates wind at the surface in the opposite direction of the trades.
So despite easterly trade winds, at the surface you may experience a westerly wind which would push your catamaran towards the shore (see the picture above when we were anchored at Muskmelon Bay - the bow is oriented towards the west as a result of being backwinded)
Given how close you have to be to shore, it can be a concern at some BVI anchorages due proximity to the shoreline - this can happen at White Bay, for example, when the wind is from the NE
Being backwinded can be acceptable if you plan for it and have enough swinging room to manage the phenomenon

Typical day in the British Virgin Islands with puffy trade wind cumulus clouds

What is the weather like in the British Virgin Islands

It’s wonderful!!

But seriously you’ll enjoy some of the best conditions for sailing anywhere.

Generally, for weather conditions, you can expect steady 10-15 knot trade winds from the ENE-ESE, puffy tradewind cumulus clouds, and an occasional shower or squall.

I like to break the BVI sailing calendar into 4 seasons:

High season: December to March
Shoulder season 1: April to June
Peak hurricane season: July to October
Shoulder season 2: November

Read about what to expect in each in my post about the best time to visit the British Virgin Islands.

Want to learn more about sailing in the British Virgin Islands? Check out my BVI Beginner’s Guide for other useful insights.

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BVI Weather and Marine Forecast Resources for Sailing