Pacific Ocean Islands

The Pacific’s dimensions are truly vast. From north to south it measures a mind-blowing 16,000km, while near the equator it’s 17,000km wide. This makes the Pacific by far the largest ocean, covering a third of the globe and accounting for half of the ocean’s entire surface area. Amongst its superlatives are the deepest depths, highest submarine mountains and largest coral reefs. Adrift in the middle of its endless waters are over 7,000 diminutive islands. Many of them lie in the tropical waters of Melanesia, Micronesia and Polynesia – often collectively called the ‘continent’ of Oceania for their common cultural roots. Most are the tips of extinct or dormant volcanoes, thickly covered in tropical vegetation. On their coasts, turquoise lagoons lap palm-fringed sandy beaches protected by coral reefs on which the waves break. Ever since the early seafarers, this has been the stuff of legend.

Centre-stage geographically, the inner tropical convergence zone sits over the equator in the austral winter (Apr-Oct) or a few degrees south in summer. With mostly weak winds, this region of rising air-mass is best avoided. The real meteorological limelight is on what happens above and below it. The sub-tropical high pressure zone located from about 15° to 35° South has predominantly easterly winds, and as the air-mass flows in towards the convergence zone the Coriolis effect skews the wind NE in the northern hemisphere and SE in the southern. These trade winds routinely provide power in the tropical waters of the Pacific Islands. They’re predominant year round, but depending on the location of the islands are distinctly more or less reliable with the changing seasons. Way out west in the southern hemisphere, New Caledonia has SE trades particularly in the local summertime (Oct-Mar), in contrast the winter (Jun-Oct) is much better on Fiji (Viti Levu & Mamanucas), Viti Levu & Mamanucas, Tahiti and Moorea. The ambient trade wind strength of Force 3-4 generally needs local thermals to accelerate beyond Force 5: strong winds are more the exception than the rule at these latitudes. When island topography doesn’t help out, like on Samoa, it’s often on the cusp of planing strength. Dec-Mar can get really stormy with tropical cyclones forming between 10° and 20° South and heading south-west towards New Guinea or Queensland.

Distinct from the South Sea Islands, Hawaii sits on the northern edge of the tropics, near the Tropic of Cancer and therefore under the influence of the NE trades all year round. But there are still seasonal variances, with a reliably windy summertime and weaker winds in winter. Thanks to topographical strengthening Maui enjoys particularly reliable winds, but Oahu still scores a respectable quota of 60% or more in summer.

In contrast, New Zealand in the deep south is outside the trade wind zone. While South Island is exposed to the stormy onslaught of the westerly wind zone all year round, conditions on North Island are a little calmer – at least in summer. Even so, the weather’s still very lively – affected as it is by rapid changes between successive high and low pressure systems as well as the ensuing warm and cold fronts. South-westerly winds frequently alternate with easterlies: “four seasons in one day” as they say. While the winds in Auckland are comparatively weak, venturi and thermal effects ensure a reliable supply of strong to very strong winds all around the 2,518m volcanic cone in Taranaki.

On top of all the other superlatives, the Pacific has something special to offer: the biggest and best waves on the planet! Spots like Jaws on Maui and Teahupoo on Tahiti are bona-fide trademark big waves. The tropical islands around the equator score groundswell out of the higher latitudes of both hemispheres, plus there’s always a chance of catching some swell from distant cyclones, hurricanes or typhoons. The biggest swell generators south of the equator are storms raging in the Roaring Forties and Furious Fifties around Antarctica. Peak season for quality swell is wintertime (Apr-Oct) with wave periods of 14 seconds or more, but even in summer there’s a really decent yield of S-SW swell. In contrast, North Pacific storms are more seasonally pronounced. The large lows moving eastward over the Aleutians Islands mainly occur in the northern winter (Oct-Mar). Their swells pound the legendary Hawaiian ‘north shores’ at full power and size, lighting up the southern hemisphere islands two to four days later, even if they are 40-60% smaller. The same applies to southern winter swells that reach Hawaii’s south coasts in summertime.

Sitting 40° South, New Zealand is beside the source, sometimes right in the middle of it. Consequently the waves can be very big, but not so clean. Taranaki profits particularly well from its exposed location, scoring anything that travels up through the Tasmanian Sea. Auckland’s west coast is sheltered from southerly swells by Taranaki and South Island, but the east coast occasionally comes alive with cyclone swell. New Zealand also stands apart from the tropical Pacific Islands due to a cooler climate (8-22°C) and chillier waters (11-18°C) so close to Antarctica. In contrast, the tropical islands inside the Tropic of Capricorn bask in 24-30°C air and 24-29°C water all year round.

Tides within the expansive Pacific Basin are modest at a maximum of 1.5m, but on shallow reefs even less than a metre can have a large affect. In New Zealand, Auckland and Taranaki have ranges of up to 3m or more so timing is pivotal.