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Hawai‘i Weather

We had Hawai‘i weather in New York yesterday, and we're having it again today. Evening at home felt a bit like evening in Kailua-Kona, which has mentally rewound my life about five weeks--very pleasant. Hawai‘i has very funny and interesting weather, though. Read on:

The Hawaiian Islands are at 20° north latitude, just south of the Tropic of Cancer. The wind blows from the east, carrying evaporated moisture from thousands of miles of Pacific waters. The vast majority of this rain falls on the eastern side of each island, where the moist air reaches the land. The volcanic slopes cast a rain shadow on the western shores, and the difference in climate is clearly visible in overhead photographs.

The extreme range of variation in rainfall, the winds and ocean currents, the steep mountains, and the eroding and evolving landscape all combine to create numerous microclimates on each island. We stayed in Kailua-Kona on our recent trip, and like most of the coastal towns the air is comfortably in the 80s (F) during the day and the 60s (F) at night. It's at the western extremes of the Big Island, so it's generally very dry, with desert lands to the north that would closely resemble the western deserts of North America were it not for the immense old lava flows draped downhill to the sea. But just five minutes upslope from the Kona coast and you're driving past rich green trees. Ten minutes upslope and you're in a cloud forest. Half an hour south and you're surrounded by farms growing coffee, mangoes, avocadoes, and macasmia nuts. An hour north and you could be in northern California. Head uphill from there and you travel through grassy plains, past the treeline, to the arid peak of Mauna Kea, where there are almost never clouds but visitors are warned of "freezing fog." One mountain to the south, the lava pouring from Kilauea causes the air to be filled with vog (volcanic fog).

We grew up in western Massachusetts, where the saying was "if you don't like the weather, wait a minute." We've had years with almost no snow, and years where there were blizzards in October or May. In Hawai‘i the temperature difference between night and day is greater than that between summer and winter. If you don't like the weather, move over a few miles.

When I say we've had "Hawai‘i weather," by the way, I guess I mean we've had Kailua-Kona weather: nearly 80° by day, nearly 60° by night. But the next few days are going to feel like a drive into the forest...

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