The world’s weather is changing. Cruising guru Jimmy Cornell explains how to future-proof your sailing and voyage planning

‘Sailing routes depend primarily on weather, which changes little over the years. However, possibly as a result of the profound changes that have occurred in the ecological balance of the world environment, there have been several freak weather conditions in recent years. The most worrying aspect is that they are rarely predicted, occur in the wrong season and often in places where they have not been known before. Similarly, the violence of some tropical storms exceeds almost anything that has been experienced before.

‘The depletion of the ozone layer and the gradual warming of the oceans will undoubtedly affect weather throughout the world and will increase the risk of tropical storms. The unimaginable force of [recent] mega hurricanes should be a warning of worse things to come.

‘All we can do is heed those warnings, make sure that the seaworthiness of our boats is never in doubt and, whenever possible, limit our cruising to the safe seasons. Also, as the sailing community depends so much on the forces of nature, we should be the first in protecting the environment, and not contribute to its callous destruction.’

Those words were written in 1994 in the foreword to the third edition of my book World Cruising Routes, but they are more pertinent than ever today. In the intervening years the global weather conditions have seen major changes, especially in the location, frequency, strength and extra-seasonal occurrence of tropical cyclones. So how can we as cruisers plan voyages in such a rapidly-changing world?

NASA satellite image shows four hurricanes affecting North America simultaneously on 15 September 2020; Katarina off Baja California, Sally above the Gulf of Mexico, Paulette near Bermuda and Teddy off the Leeward Islands, while wildfires rage from California to Colombia

Warmer oceans

In its sixth assessment of the impact of climate change, published in April 2022, the Intergovernmental Panel on Climate Change warns that climate change is causing dangerous disruption in nature and is affecting billions of people, stressing the urgency to act.

  • The oceans are getting warmer
  • The Arctic ice cap is melting at a faster rate than in any recorded times, as reported from Greenland this year
  • Tropical storm seasons are less clearly defined and becoming more active
  • Extra-seasonal tropical storms are more common
  • The Gulf Stream rate is slowing down
  • Coral is dying due to ocean warming

According to a report published in 2022 by the International Union for Conservation of Nature, the astonishing pace of warming in the oceans is the greatest hidden challenge of our generation, altering the distribution of marine species from microbes to whales, reducing fishing areas and starting to spread disease to humans.

Rising sea temperatures are thought to be a factor in the jump in tropical storm activity

This comprehensive analysis of ocean warming states that if the oceans had not already absorbed an enormous amount of heat due to escalating carbon dioxide, the atmosphere would be 36° warmer.

Warmer ocean temperatures, combined with higher sea levels, are expected to intensify the impact of tropical storms. Areas affected by such storms are already shifting poleward. According to the NOAA (the USA’s National Oceanic and Atmospheric Administration) an increase in Category 4 and 5 hurricanes is likely, with hurricane wind speeds rising by up to 10%.

Devastation after Hurricanes Irma and Maria hit the Caribbean in 2017. Photo: Sharpshotaero/Alamy

Storm seasons

As a sign of the intensification of the climate emergency, the 2020 North Atlantic hurricane season was the most active on record. Of the 30 named storms, 13 developed into hurricanes, and six intensified into super-hurricanes. The current La Niña episode is expected to cause another active Atlantic hurricane season. Forecasters at NOAA’s Climate Prediction Center are predicting an above average hurricane activity in 2022. This would make it the seventh consecutive above-average hurricane season.

The timing of the cyclone seasons is an essential factor in voyage planning and one of the results of climate change is that tropical storms are now occurring outside the accepted time frame. Although the official North Atlantic hurricane season continues to be considered to last from 1 June to 30 November, in recent years several hurricanes have occurred as early as late May, or as late as the end of November. In the last 10 years, five of the 161 hurricanes occurred in May. The earliest among them was hurricane Ana from 8-11 May 2018, which affected the south-east United States. The latest hurricane in recent years was Otto, which caused much damage in southern Central America between 20-25 November 2016.

These factors must be taken into account when planning a passage to or from the Caribbean, and arrivals in the Eastern Caribbean should be planned for early December.

An active 2022 hurricane season is also expected in the North Pacific in the area between Mexico, Central America and Hawaii. The behaviour of hurricanes here is similar to that of the North Atlantic and the storm season, officially lasting from 15 May to 30 November, is also lengthening. Among the 205 hurricanes recorded in the last 10 years, nine have occurred in May, four in the first half of the month. The earliest, Andres, occurred between 9-11 May 2021, while the latest, Sandra, struck between 23-28 November, also in 2021.

Be prepared for the unexpected. Photo: Tor Johnson

These examples have a direct bearing on voyage planning and show the importance of not arriving in the critical area before early December and leaving it before early May.

In the north-west Pacific both the frequency and force of typhoons is on the increase, with some super-typhoons having gusts of 200 knots or more. Typhoons have been recorded in every month of the year, with a well-defined safe season now a thing of the past.

In the North Indian Ocean the severity and destructive power of the cyclones has also intensified. The 2021 season recorded five cyclones, among them two severe cyclones, while the 2020 season recorded five cyclones, four of them of severe intensity. The trend in the southern hemisphere points in the same direction. In the South Indian and South Pacific oceans the cyclone seasons last longer, and the frequency of extra-seasonal cyclones has also increased – in the Coral Sea extra-seasonal cyclones have been recorded as late as June, July and even September.

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Mitigating risk

I have been monitoring global weather conditions since the 1980s both for my own interest and to update my various books (including World Cruising Routes, now in its ninth edition). Another valuable source has been the findings from regular surveys among long-distance sailors I’ve been conducting for over 40 years. I have interviewed more than 50 sailors on their views on climate change and its effects on future voyages. Most are active sailors, with the majority having completed at least one circumnavigation.

In a similar survey on voyage planning conducted in 2018, there were still a few who had doubts about the seriousness of this global phenomenon. However, this time, with one exception, everyone I spoke to agreed that the threat posed by the changes in climatic conditions posed a serious threat to future voyages (besides the wider danger to mankind itself).

Cruisers enjoy the Tobago Cays in the Grenadines. Forward planning is needed to leave a yacht in traditional ‘safe’ zones such as Grenada. Photo: Peter Phipp/

Some of those who contributed to the survey also expressed other concerns, such as the overfishing of the oceans, the pollution that is now reaching even the remotest parts of the world, the threat to tropical atolls and low-lying land areas, and the displacement of their populations. Another area of concern is the change in the attitude of local people towards visiting sailors. This was highlighted by several incidents during the Covid pandemic when many countries imposed draconian restrictions on visiting boats, which could not then continue their voyages.

To complete the survey, contributors were asked whether climate change would influence their decision, were they to plan a world voyage now. With only one exception, all stated that while they were aware of its considerable effects, they would take that factor into account but would still be prepared to plan and leave on a long voyage.

Bearing in mind the changed circumstances, these are a few basic safety measures that should be adhered to when planning a voyage now or in the near future:

  • Ensure you do not arrive in the tropics too close to the start of the safe season, and allow a safe margin by leaving before its end
  • Avoid cruising during the critical period and preferably leave the tropics
  • At all times, monitor the weather and have a Plan B to deploy in case of an emergency
  • If you plan to leave the boat unattended, make sure your insurance company is informed and agrees with your plans.

When it comes to insurance, Ric De Cristofano, director of underwriting at Topsail Insurance, explained: “Climate change is likely to be the main topic for insurers over the next decade.

Cornell’s route through the Northwest Passage in 2015 on Aventura IV in blue, and the shrinking of the polar ice cap (yellow)

“There is absolutely no doubt that climate change is triggering more extreme weather events around the globe and most insurers have internal modellers who are forecasting a higher frequency and severity of hurricanes, and even of lesser weather events, such as electrical storms.

“Insurers are building these into their loss modelling now for future pricing. The impact on boat owners planning to go cruising will be both direct and indirect. The former is likely to include increased coverage restrictions along the lines of no Caribbean windstorm cover and for such risks to be rated higher by insurers.

“As for the latter, the insurance industry is preparing itself for large and catastrophic insurance events to become more frequent, which ultimately will lead to cost increases across a whole range of services.”

Survey respondents also stressed the even greater importance of having reliable access to weather information in a world of changing conditions. Nick Olson, development manager at PredictWind, pointed out that: “Weather events will be more extreme, but that is the type of event we aim to avoid already. Seasonal planning should not change greatly, as what we do already is try to avoid extreme weather.

“We have some new tools aimed at extreme weather coming online in the next few months. One will alert you when there are factors which could produce extreme weather that would trigger potential thunderstorms.

Aventura in the ice

“Another extreme we might see is having more light winds. Our departure planning and weather routing tool both rely on forecast modelling, which will adapt to climate changes and predict the expected conditions like they do now in producing the short term forecasts. Being able to see the expected conditions, whether extreme or the opposite, and thus help avoid what we don’t want to be caught in, is the basic premise of what we do.”

High latitudes

One visible effect of climate change is the increasing numbers of sailors heading for high latitudes in the belief that climate change in the polar regions would result in more benign conditions. I benefited from this myself with a successful transit of the Northwest Passage in 2015, which was indeed possible as a direct result of climate change. The Northwest Passage has been described as the ‘canary in the coal mine’ of climate change because whatever happens there will eventually have repercussions for climate conditions in other parts of the world. Voyages to Antarctica may fall in the same category, and no one is in a better position to comment on this matter than Skip Novak, widely considered as the world’s authority on polar sailing.

“With respect to the impact of climate change on voyaging to the far south there are two things at play; weather and sea ice concentrations. For those of us who sailed regularly in the Southern Ocean from 40 years ago, the consensus of colleagues (both racers and cruisers) is that sea conditions seem much more volatile than before,” says Novak.

“One theory of substance is that in the Southern Ocean the westerlies are being compromised by winds pushing through this band from the north, certainly more often than in previous decades. This causes the steady long swells we have formerly experienced to be less consistent with more ‘washing machine’-like conditions.

“To postulate on sea ice concentrations for navigation is tricky. For sure, temperatures on the Antarctic Peninsula have spiked up from 40 years ago, but this does not necessarily mean less sea ice in the archipelago in any given year. A cold winter and lack of strong winds in spring into summer will see inshore waters choked, sometimes into late January. It remains, as it has always been, the luck of the draw on where you can go.”

Pete Goss cruising in his formerly owned Garcia Exploration 45 Pearl of Penzance. Photo: Jason Pickering


Skip’s observations go to the core of the matter – there is, as ever, a large element of luck – and I was pleased to learn that none of the sailors I interviewed would be deterred and abandon their plans. Most appeared to have considered seriously the possible risks involved when planning their route and places visited and were confident that, if necessary, there would be a solution.

Some of the most experienced and well travelled among them, such as Pete Goss, stressed the importance of “having a well built, strong boat that you have confidence in and that would be able to stand up to the weather, and ensure you survive it.”

Former naval officer Eric Abadie, currently on a world voyage on Garcia Nouanni 47 Manevaï, is more concerned by the “impact in the visited countries, both because of the climate change itself and the political disorders induced by the climate change in those countries.”

He adds: “As for me, it’s on the water that I am truly happy. And that will not change!”

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