Best Time of Year for Snorkeling on Oahu
The summer months, from June to September, generally offer the best overall conditions for snorkeling on Oahu. The water temperature during these months are at their warmest, averaging around 80−82∘F (27−28∘C) on the south shore (Waikiki) and slightly cooler but still very pleasant on the west side. This is comfortable for extended periods in the water without a wetsuit for most people. The visibility during the summer typically brings calmer seas, less rain, and higher visibility, making it easier to spot colorful fish, sea turtles, and other marine life among the coral reefs. While monk seals, turtles and dolphins are not seasonal in Hawaii, during the summer months there can be more monk seal and green sea turtle sightings because they are often more active and visible in the calmer shores. On Oahu’s western shoreline, the dolphins tend to play in the southern shores close to Nakakuli during warmer months.
While not everyone can travel in high season, shoulder seasons (Spring: March-May and Fall: September-November) are also excellent choices to explore the islands. The fall brings good water clarity and a chance for late-season turtle sightings. In the spring, the ocean begins to calm down from the winter surf, and water clarity improves which makes for great snorkeling. Dolphin sightings are common and March and November are on the cusp of the exciting whale watching season!
Alas our wonderful winter (December-February) season. Hawaii’s winter is often marked by high surf and more wet conditions. The north and some northwestern facing shores experience large swells during winter, making it a world-renowned surfing destination but unsuitable for beginner snorkeling. (Check out the Eddie Big Wave Surf Contest or Pipe Masters to see how amazing and massive the waves can get!) However, the beautiful thing about Oahu is that by changing shorelines, you can often find different conditions that may be more favorable for your chosen water adventure. Although winter can be challenging for snorkeling on the north shore and east side, south and western shores generally remain calmer and safe for snorkeling tours even in winter.
Another prime highlight of winter in Hawaii is whale season. Winter (December-March, with peak viewing in January and February) is the prime time for humpback whale watching on Oahu. While not a direct snorkeling activity, many tours combine whale watching with snorkeling opportunities on the calmer leeward (west) side of the island. Ko Olina Ocean Adventures combines this exciting type of excursion for you.
Whichever season your travel plans may end up bringing you to the islands, there are great chances that with the proper local knowledge and guidance, you can find a great shoreline to snorkel and explore..