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With pleasant temperatures, lower chances of rain, and smaller crowds, September is one of the best times to visit Hawaii. If you’re short on time, here’s a quick answer: Hawaii sees warm, mostly dry weather in September with average highs around 85°F and lows in the mid 70s.

Expect blue skies, moderate humidity, balmy ocean temperatures, and fewer tourists.

In this comprehensive guide, we’ll cover everything you need to know about Hawaii’s weather in September including temperature, rainfall, humidity, ocean conditions, and events that could impact your travel plans.

We’ll also compare September to other months and help you determine if it’s the ideal time for your Hawaiian vacation.

September Brings Ideal Hawaiian Temperatures

Daytime Highs Average in the Mid-80s

When it comes to daytime highs, September brings some picture perfect weather to Hawaii. According to records from the National Climatic Data Center (NCDC), average temperatures across the islands range from the mid-70s to the mid-80s during the afternoon and early evening hours (NCDC data).

For example, Honolulu sees typical highs around 86°F while Kahului reaches 84°F. These mid-80-degree temps allow for comfortable outdoor exploring without excessive heat or humidity.

Nightly Lows in the Comfortable Low 70s

In addition to pleasant days, September nights in Hawaii are also quite enjoyable. Overnight lows drop down to the low 70s on average, with places like Hilo and Lihue seeing temps in the 71°F-72°F range (NCDC records).

These cooler yet mild evenings lend themselves perfectly to sunset dinners on the beach or cozying up at your island accommodation after an action-packed day.

Warmest Weather on West Coasts, Coolest in the Mountains

While weather varies slightly across the Hawaiian islands in September, some trends emerge based on location and elevation. The NCDC shows the following geographic differences:

  • West and south shores generally see the warmest weather while north and east shores run a bit cooler.
  • Lower coastal regions experience higher temps than mountain areas at higher elevations.
Location Average High Temp
Kona, West Coast 86°F
Haleakala Summit, Over 10,000 Feet Elevation 59°F

So when making Hawaiian travel plans, keep September’s ideal weather in mind along with warmer temps on coasts and cooler mountain climates. With average highs in the 80s and lows in the 70s, conditions will be perfect for everything from sunbathing on the shores to epic hikes through lush inland rainforests.

Less Humid Than Summer With Comfortable Ocean Temperatures

Humidity Drops from August Highs

One of the best things about September’s weather in Hawaii is the drop in humidity compared to the summer months. While the islands do stay moderately humid year-round, levels in September average around 66% according to Weatherspark. This is down from the August average of 70% humidity.

The more comfortable moisture levels are aided by the cooling trade winds flowing in off the ocean.

With less muggy air prevalent, being outdoors enjoying Hawaii’s beautiful landscapes and beaches is more pleasant without becoming overwhelmed by heat and stickiness. Whether sightseeing or being active, the dip in humidity is welcomed.

Pleasant Trade Winds Keep the Air Feeling Fresh

The cooling breezes Hawaii is famous for, called trade winds, continue flowing consistently in September. These winds originate from the northeast and travel across the islands at speeds around 12 to 15 mph.

The trades not only moderate the heat of the day, but provide a fresh ocean air feeling. Sunbathing on the beaches is more enjoyable with the winds blowing. And views from high elevation lookout points stay clear rather than hazy thanks to the circulation.

Statistics from Current Results show September as having the second highest average wind speeds annually in Hawaii behind July. So visitors can expect plenty of breeze to keep hot afternoons and evenings comfortable.

Hawaiian Waters Stay Consistently Warm

While the air temperatures fluctuate some in September, the ocean waters around Hawaii stay bath-like throughout the year. In September, the average sea temperature only cools about 2°F from August to reach 79°F.

With the tropical sun still blazing, hitting the beach or even snorkeling for hours is delightful. Surfers can also catch waves wearing just swim trunks rather than full wet suits thanks to the minimal variation.

Month Average Ocean Temperature
January 77°F
May 79°F
August 81°F
September 79°F

So while the air cools a bit and dries out, visitors can look forward to warm Hawaiian waters for aquatic adventures throughout September and beyond. The stable ocean temperatures coupled with pleasant humidity and consistent trade winds make it a fabulous time to visit.

Lower Chance of Rainfall Compared to Other Months

September Sees Less Rainfall Than Summer

According to AccuWeather, September is one of the driest months in Hawaii. The summer months of June, July, and August see the most rainfall due to tropical storms and warmer ocean temperatures causing more evaporation and convection processes.

However, as fall begins in September, the rainfall decreases statewide. For example, Honolulu averages 0.1 inches less rainfall compared to August. The chances of significant rain events impacting outdoor plans drops off significantly making September an ideal time to visit.

Fewer Tropical Storm Threats

September falls in between the peak Pacific hurricane season of August-September and secondary peak of October-November. Hawaii sits in the central Pacific Ocean, so it’s vulnerable to tropical storms during summer and fall.

However, the statistical chances of a direct hit from a Pacific tropical storm drops in September as high pressure systems start developing more consistency over Hawaii according to the

NOAA Climate Prediction Center. Fewer tropical threats mean calmer weather patterns with more consecutive rain-free days. This makes for excellent beach weather and ideal conditions for outdoor activities across the islands.

Best Weather on Leeward Coastlines

Keep in mind, September’s weather does vary by each island’s unique geography. Many Hawaiian islands are split by mountain ranges creating a windward (east facing) side and leeward (west facing) area. The windward coasts experience more clouds and rain due to orographic lift from the mountains, while leeward coasts are drier and sunnier as rain shadow effects dominate.

September sees peak sunny days on the leeward coastlines of the Big Island, Maui, Molokai, and Oahu. So for island hoppers, the western beaches and resort towns like Kanapali, Ko Olina, and Kona offer peak September weather monthly averages for swimming, snorkeling, golf, and more outdoors events.

Smaller Crowds and Great Events

Visitor Numbers Dip After Summer Rush

September is technically still summer in Hawaii, but the crowds from July and August start to thin out. Kids are back in school on the mainland, so many families will wait to travel during more convenient school breaks.

Still, with average temperatures hovering in the 80s, September remains a popular time to visit the islands.

According to the Hawaii Tourism Authority, on average about 245,000 visitors come to the Hawaiian Islands in September. While still busy, this is quite a bit less than the 315,000 average visitors that come during the peak summer months.

So while the crowds may be smaller, some travelers actually prefer September for that reason – allowing them to have the beaches and attractions a bit more to themselves!

Prime Time for Ocean Sports

If you love water activities, September is a prime month to enjoy Hawaii’s famous snorkeling, swimming, surfing, paddle boarding and even whale watching opportunities, with water temperatures still warm – generally between 78-82 degrees Fahrenheit depending on location.

Ocean conditions also tend to be calmer in September than during the blusterier winter months. This makes for excellent conditions for snorkeling to spot Hawaii’s bountiful and colorful sea life. Sites like Hanauma Bay on Oahu or Kealakekua Bay on the Big Island offer some of the best snorkeling in September when water visibility can extend up to 150 feet!

Surfing is always popular in Hawaii, and September brings fun-sized swells that are ideal for beginner and intermediate surfers. Experienced surfers can still find challenging waves, especially on Oahu’s famed North Shore which starts to see larger winter swells arrive in September.

Celebrate Aloha Festivals and Hawaii Food & Wine Festival

September brings several can’t miss festivals and events to the Islands that celebrate Hawaiian culture. The Aloha Festivals occur throughout the month across all Islands, featuring parades, concerts, food fairs and cultural displays.

Highlights include the Aloha Festivals Floral Parade on Oahu and the Aloha Festival’s Hoʻolauleʻa Block Party.

Food lovers will also enjoy attending the Hawaii Food and Wine Festival which takes place on Oahu and Maui in September. This culinary event allows attendees to sample dishes from acclaimed local chefs and restaurants, experience cooking demonstrations, attend exclusive dinners and more.

The Perfect Time to Visit Paradise

September is a fabulous time to visit Hawaii. With pleasant temperatures, fewer crowds, and lower prices than the busy summer months, it’s arguably the best time of year to experience the Aloha State.

Idyllic Weather

Hawaii sees warm and sunny weather year-round, but September brings especially gorgeous conditions. Daily highs reach the mid-80s Fahrenheit, while nighttime lows dip to the balmy low 70s. Trade winds keep things breezy and comfortable.

With an average of just 1-3 inches of rain this month, skies stay clear for beach days and outdoor adventures.

Smaller Crowds

By September, most schools are back in session so Hawaii’s crowds thin out. You’ll encounter shorter lines, easier restaurant reservations, and more space to spread out on the island’s famous beaches. September occupancy rates are 30-50% lower than the packed summer months, so you’ll have more elbow room to relax and soak up the island vibes.

Lower Prices

With smaller crowds comes relief for your wallet. September airfare and hotel rates see significant drops from the high summer season. According to travel experts, September is one of the cheapest months for plane tickets to Hawaii. Savvy travelers can save hundreds of dollars by planning a fall trip.

From comfortable weather to bargain prices, September is a magical month in paradise. The islands will charm you with warm sunshine, lush landscapes, and the welcoming spirit of aloha. Why not escape the early fall chill on the mainland by booking your Hawaiian dream vacation?

Conclusion

With sublime weather featuring sunny skies, warm ocean water, and fewer rainstorms, September is undeniably one of the best times for a Hawaiian vacation. The moderating fall temperatures keep things comfortable while lower humidity and smaller crowds ensure a relaxing trip.

If you’re planning a trip to Hawaii, pencil in September for ideal weather conditions to hike volcanic cliffs, lounge on golden beaches, feast at food and wine celebrations, and fully experience the islands’ aloha spirit.

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