Weather patterns can be an important part of deciding when to plan your Kauai vacation. We want to provide you with plenty of Kauai weather data to help you make an informed decision.
Before we dive into the details, bear in mind that weather history is a fairly descent predictor of future weather. It’s the best tool we have. However, an unusual weather pattern could easily change the actual weather experience. That is true of any destination, not just Kauai.
Average Kauai Temperatures
Let’s start with the high and low temperatures. The following graph shows the average monthly high and low temperatures based on weather data collected at the Kauai airport in Lihue. Lihue is a town that’s very close to sea level and is therefore fairly representative for all the Kauai beach resorts. As you can see from the chart, Kauai’s weather is pleasantly warm year-round. Even in the coolest month of January, daytime highs average 78 F and the evening lows dip to 65 F. August is the warmest month with daytime highs averaging 85 F and cooling off to 75 F in the nighttime. (To convert temperatures to Celcius, use this link.)
Kauai Rainfall Data
Before we look at Kauai rainfall details, we want to highlight one very interesting pattern about rain in Hawaii — more rain falls overnight than during daytime hours. Rain showers are usually brief. So, keep that in mind as you are considering this data.
Even though winter months tend to be a little wetter, we wouldn’t hesitate to book a Hawaii vacation in the winter. In fact, we tend to go to Hawaii quite often in the winter because we love the humpback whale season in Hawaii. Even in the wetter, winter months, t’s been very rare that we’ve encountered rain. We’ve never had a full day that was a complete rainout.
Rain in Hawaii brings some benefits that we tourists enjoy. Rain makes the pretty waterfalls flow. (Note that some waterfalls dry up or are only a trickle after a dry summer.) The rain makes Hawaii’s delicious produce grow and the flowers bloom. Last, but not least, after a shower, one of Hawaii’s famous rainbows can be seen.
The following chart shows the average monthly rainfall levels based on data collected at Kauai’s main airport in Lihue. With 2.3 inches of rain or less, the driest months range from April through September. The rainiest month is December at 5.2 inches of rain.
Another point to note about the above rainfall chart is that the significant increase in rainfall between February and March is partially due to the fact that March has more days than February. When we further investigated it, rainfall levels in March were still slightly higher in March as compared to February, which is not as dramatic as the chart appears at first glance.
As you are reviewing rainfall levels throughout the year, another aspect to consider are the micro-climates on the island. Some areas are drier than others. The following map shows the annual rainfall by area.
Additionally, take a look at the following Bing bird’s eye view map of the island. The darker greener areas experience the most rainfall.
From these two maps, take notice that the popular resort area of Poipu is the driest region, followed by the east side towns of Kapaa and Lihue where many hotels and vacation rentals are. On the North Shore, Princeville is a popular destination with vacation accommodations even though the region gets more than twice the amount of rain as the east and south resort areas. Does that mean that if you choose to stay in Princeville you’ll constantly experience rain? That’s highly unlikely! Remember that most rain falls overnight and rain showers are usually short. That all being said, if you are planning a vacation during a month with above average rainfall levels, it might be a good idea to stay in east or south resort regions to minimize rain. There are no guarantees for better weather, but based on history and probability it’s a safer bet.
If you are torn between where to stay on Kauai, consider splitting your time between the different climates. See our post on two different vacation experiences on the same Hawaiian Island.
In addition to the Kauai rainfall data, we want to share some of our personal experiences with Kauai weather. We’ve visited Kauai in the months of February, April, May and October. In all those visits, we’ve only experienced one rainy day that ruined our plans. Ironically, that rainy day was in one of the driest months — May. We were also staying in one of the driest regions — Poipu.
Ocean Temperature around Kauai
You can swim year round in Hawaii. For more details, see our Hawaii ocean temperatures article.
Humidity in Kauai
Per the data on this page, the average humidity is in the low to mid 70%. Most people will agree that 70% is pretty high humidity. Thankfully the prevailing tradewinds from the northeast, keep you comfortable despite the humidity. Occasionally, Kona winds from the southwest make the atmosphere feel hot and sticky.
To keep more comfortable in humid weather, we recommend that you stay in a place that has ample air conditioning. We spent a couple of nights in a Poipu condo without air conditioning one April. With a ceiling fan on, by late night, we’d start to feel comfortable in the condo. We vowed then to always stay in accommodations with air conditioning.
Wear light, breathable clothing to help you feel more comfortable in the Kauai humidity.
Hurricanes in Kauai
The last hurricane, Iniki, that hit Kauai and caused any major damage was in 1992. Hurricane season in Kauai, which runs from June through November, is usually quiet, however 2015 has been an unusually busy season for tropical storms.
Have you been to Kauai? What time of year did you go and what was your experience with the weather?