There isn’t really a bad time to visit Kauai. The worst of the Garden Isle’s tropical weather, for the most part, still feels like a dream to most vacationers from the U.S. mainland and other more temperate climes.
And compared to those latitudes, Kauai’s weather is usually quite predictable and, in many respects, similar throughout the year. The island’s location near the northern edge of the tropics makes for balmy temperatures all year-round, with not a whole lot of difference between summer and winter. Daily highs on Kauai tend to range from the upper 70s to the mid-80s.
Short of a landfalling hurricane—quite rare in the Hawaiian Islands—the most disagreeable weather (at least in your average tourist’s eyes) on Kauai is rain. And it’s true that Kauai gets a lot of rainfall: In fact, the misty heights of Mount Wailaleale, with more than 400 inches of average annual precipitation, maybe the rainiest place on Earth. But the subject of rain on Kauai must be qualified by a couple of fundamental points.
First, the distribution of rainfall is far from equal. The leeward side of the island is much drier than the windward side, and it’s often surprisingly easy to track down clear skies even during the rainy season. And second, all of that rain gives Kauai its magnificent “Garden Isle” lushness, plus its dramatically water-carved scenery—countless waterfalls included—and plentiful rainbows.
In this guide, we’ll sketch out the basic framework of Kauai’s weather, provide some month-by-month stats, and discuss a few travel considerations related to what the island sky’s likely to be doing at a given time of year.
Kauai’s Weather: A Snapshot
Kauai’s generally wonderful weather is dominated by the trade winds. These northeasterly breezes flow off a large, persistent high-pressure cell: the Pacific High. Over the open ocean near Hawaii, the average annual rainfall is only about 20 or 25 inches. But on mountainous Kauai, the trade winds are forced upslope, producing clouds and precipitation. The windward side of Kauai, therefore, gets a healthy amount of rain, amounts increasing upwards with elevation to max out around Mount Waialeale. (The soggy, mostly trackless Alakai Swamp on the Olokele Plateau below Wailaleale is one reflection of all that rainwater.)
Kauai’s high interior casts a rainshadow. The wrung-out trades warm up and dry out as they descend the leeward slope. The driest parts of the western and southern coast receive 20 inches or less of average rainfall. That’s an amazing contrast across a small area when you consider the 70-plus inches of rainfall the North Shore can receive and those hundreds of inches of rain falling in the mountains.
The Pacific High tracks north and south throughout the year along with the Sun. In the summertime, the high moves north and tends to be at its strongest. This makes for the steadiest influence of trade winds on Kauai of the year. Trade-wind weather, with clouds often forming against the windward slopes and plentiful sunshine elsewhere, prevails about 90 percent of the time in the Kauai summer.
In winter, the Pacific High moves south and weakens. The northeasterly trades are still the dominant weather pattern over Kauai, but they’re frequently interrupted by other systems. Winter is the stormiest season on Kauai. A typical winter sees at least a few significant bouts of heavy rains and gales from Kona storms, cold fronts, and upper-level low-pressure systems. In contrast to trade-wind weather, such disturbances can bring southerly winds and island-wide rainfall.
The Kauai summer is the dry season, the winter the rainy season. But given the regular rainfall of windward Kauai in summer, these distinctions are a little misleading.
Month-by-Month Weather on Kauai
Below are monthly average high and low temperatures and precipitation for Lihue on Kauai’s eastern shore (the Coconut Coast). These figures are only a rough guide, though. We’ve already discussed how dramatically rainfall varies across the island. Leeward towns such as Kekaha and Waimea are a lot drier than Lihue. Also, remember that temperature generally decreases with elevation, and there’s quite the elevational spread on Kauai. Conditions up in the Kokee highlands, for example, are liable to be cooler—maybe significantly so—than the coastal resort hubs.
For the following, temperatures are given in degrees Fahrenheit.
January
Average High: 78
Average Low: 65
Precipitation: 4.59”
February
Average High: 78
Average Low: 66
Precipitation: 3.26”
March
Average High: 78
Average Low: 67
Precipitation: 3.58”
April
Average High: 79
Average Low: 69
Precipitation: 3”
May
Average High: 81
Average Low: 70
Precipitation: 2.87”
June
Average High: 83
Average Low: 73
Precipitation: 1.82”
July
Average High: 84
Average Low: 74
Precipitation: 2.12”
August
Average High: 85
Average Low: 74
Precipitation: 1.91”
September
Average High: 85
Average Low: 74
Precipitation: 2.69”
October
Average High: 83
Average Low: 73
Precipitation: 4.28”
November
Average High: 81
Average Low: 71
Precipitation: 4.7”
December
Average High: 79
Average Low: 68
Precipitation: 4.78”
The Best Time to Visit Kauai From a Weather Standpoint
The high tourist season on Kauai comes in winter, aka the rainy season. While this is statistically the wettest and stormiest time of year, the weather on the island is still a heck of a lot nicer than most parts of the U.S. in winter. Rain showers are often on and off, with plenty of sun breaks. A Kona storm might bring a couple of days of wetness but is unlikely to completely spoil your vacation.
In the summer dry season, you’ll still likely encounter occasional trade-wind showers (and cloudiness) on the windward side, but these aren’t much of an issue. Heading over to the leeward side of Kauai—to Poipu, say, or Waimea Canyon—will typically get you into the sunshine.
Between July and November is the window for tropical cyclones and hurricanes potentially influencing Kauai. These are fairly rare in the Hawaiian Islands and come with plenty of advance warning. Direct hits by hurricanes are very uncommon here, but storms passing close to the islands can still bring strong winds and torrential rains.
Long story short, you can usually expect nice, warm temperatures—kept from being uncomfortably hot by the moderating ocean influence—whatever time of year you visit. During the trade-wind weather that predominates most of the time, rain is rarely totally disruptive, and you can generally hunt out sunshine somewhere on the island. The winter brings occasional storms that usually provide the heaviest and most prolonged rainfall, but there may be only a handful of these in a normal year—and sometimes none at all.
Really, compared to a lot of travel destinations in the world, Kauai and the rest of Hawaii offer pretty spectacularly nice weather throughout the year!
