Whether we are in port, at anchor or - most importantly - out sailing we need to keep a close eye on what the weather is up to and how it will affect us. Key to this is always monitoring the weather and forecasts, making judgement calls when passage planning, and once well out to sea adapting as best as we can to the conditions. Wherever we are it is crucial that we maintain access to accurate forecasts. To collect weather info we use the internet, our single side band radio (SSB), VHF, AM/FM radio and historical data.

Below we talk about historical information and how this will shape our 2007 Atlantic Crossing. Use the navigation bar on the right hand side to view the other sources of data we use.

A very important way of predicting the weather especially the general trends is to consult records of previous years. Atlantic pilot charts give data for each month collected from ships over 150 years. “World Cruising Routes” uses the same data but also consults sailors, some of whom have made the trip several times, to find what to expect on different routes. The main sources we have used are:

The Atlantic Pilot Atlas 4th Edition - James Clarke

World Cruising Routes, 5th Edition - Jimmy Cornell

A study of these sources for our planned trip across the Atlantic this year suggests the following:

Late April, May, June and July are the best months for the trip. Earlier is no good as during the winter and early spring depressions from US sweep low into our route home. Later is not as good because the chances of meeting a hurricane start to increase from July onwards as the summer sun heats the seawater.

First thoughts would suggest a direct route between Virgin Is and Britain but the charts reveal that the winds of the Atlantic swirl around in a big circle blowing eastwards in the north part and westwards down near the equator. In the middle the wind is weaker and more unpredictable. As such we should head north to catch those favourable winds and then get blown across by them. Conveniently this takes us past Bermuda and gives the opportunity for a rest.

Virgins or Puerto Rico to Bermuda, 830M, course 000 (north), April and May.

First half of passage – 0% gales, 3% calms. Predictable easterly winds (i.e. blowing from the east to the west) F4 for both months with a west-going current of 0.5 knots.

Second half of passage – 2% chance of gales in April, 0% gales for May, 3% calms. Progressing north the most common wind direction changes from E to W in April and from SE to SW in May (all F4), but winds are more variable here so it could come from any direction especially in April.

Bermuda to Azores, 1700M, course 070-085, May and June

3% gales in May, 1% gales in June, (7% gales in April). 2-3% calms

At 32N Bermuda lies in a latitude of light and variable winds. Heading north of the direct line to Azores should give more dependable and generally SW4 winds. Near 40N the winds are much better especially in June but the conditions are colder and the risk of icebergs and gales increases. A balance needs to be struck. Approaching Azores takes the route south of the best winds once again (expect W or WNW4 with 5% chance of calm) but may provide a welcome rest and the opportunity for re-provisioning.

Azores to Ireland, 1200M, course 050-060, June and July

1% gales, 2-3% calms once away from Azores

By mid summer the Azores high is well established driving useful sailing winds in many places other than in the Azores themselves. Expect light variable and possibly northerly winds for the first part of the passage (5-7% calms in this area). A direct route to the English Channel risks being swept toward the Bay of Biscay by NW winds and current of the Portuguese trades, better to head north and catch more favourable W (average F4 and 0.5 knots) winds and current. The pleasant sunny climate of the Azores will change to damp and cooler 'English Channel weather' as you head north and catch the westerly winds.

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