The summer months see slightly higher temps by a few degrees, perhaps high-80's instead of the mid-'80s, but the summery half of the year is marked by consistently dry weather. The winter months, on the other hand, are known for rainfall, but it's not what you may think.
The average winter day starts off beautiful and the humidity gains throughout until it breaks with a short shower in the late afternoon. There are no monsoons and only the rare tropical storm. The "wet season" shouldn't deter you from your dream Hawaiian vacation.
You can use these semi-daily showers to your advantage on the Waimano Falls and Pools trail. Simply head out on the trail early in the morning after the heaviest afternoon rainstorm. The falls and pools are almost guaranteed to be enjoyable.
Waimano Falls and Pool's wintertime advantage doesn't stop there. Winter brings violent surf to many of Oahu's beaches, and, on the flip side, summer tends to bring glass-calm ocean conditions. So, on a particularly dangerous ocean day, you can take this inland hike to enjoy a cool swim and a tropical waterfall.
The trailhead is only 25 minutes north of Honolulu. Take H1 West out of Hawaii's largest city for about 10 miles then take Exit 10 to Pearl City. Merge onto Moanalua Road then use the right two lanes to turn right onto Waimano Road. Follow Waimano Road for about three miles before turning left onto Komo Mai Drive where you'll find a small parking lot hidden inside of a neighborhood.
Parking is limited inside the neighborhood, and make sure not to park on the neighborhood's streets. You'll most likely get a ticket. Make sure to show up early in the morning to get a spot, and, if you're really worried about the crowd, then make sure to come here on a weekday.
The first two-thirds of the trail takes place on an old paved road that winds its way through dense rainforest. You won't have any spectacular views on this trail, but the real reward is the waterfall and pool at the end. Make sure to follow the trail marked by pink ribbons tied to trees. Otherwise, you could end up on the Ko' olau Mountains Trail which takes you five miles out of the way.
The trail is relatively easy, but there is one caveat -- Cardiac Hill -- and you'll instantly know it when you see it. A quilt of exposed and interwoven tree roots cover the daunting hill to provide a series of tangled steps. This rip-rap is an ankle breaker, so watch your step and wear some sturdy shoes.
After Cardiac Hill, you'll traverse some narrow and muddy pathways to the big waterfall and its pools. Well, you'll be greeted by the waterfall and pools so long as there's been recent rain.
The water cascades into a narrow slot canyon where you'll find a deep pool during the rainy season. You'll also notice a rope swing tied to trees high above the pools. Locals like to use the swing for jumping into the pools when they are deep.
If you plan on using the rope swing, then make sure there are locals there making the jump. You can watch them in order to learn how to do it safely, and perhaps they'd be kind enough to instruct you. Otherwise, you should stay off the rope swing and choose not to jump into the pools from the canyon's cliff sides.
The pool is incredibly narrow and will likely be full of a few people. It takes knowledge and careful consideration to pull off a jump safely. And remember, you're a long way from help should you get injured.
Otherwise, it's time to enjoy the rushing 14-foot waterfall and its cooling pools. The water here tends to be a little clearer than other inland waterfalls because it's seasonally dependent. So make sure to pack an underwater camera for all of the adrenaline-filled fun, and make sure to save some energy for Cardiac Hill on your way out.