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Honolulu in September

Honolulu Weather in September

🇺🇸 United States

28°C
High
24°C
Low
8
Rain Days
12h
Sunshine
78%
Humidity

North America › 🇺🇸 United States › Honolulu

Updated: March 2026

Is September a Good Time to Visit Honolulu?

7/10
Good

September is a good time to visit Honolulu (7/10). With 12 daily sunshine hours and only 8 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 6th sunniest of the year in Honolulu. Culture-focused travellers and those who prefer lighter crowds will find September a practical choice, with prices running lower than peak May without sacrificing all the good weather. October offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Honolulu's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.

vs August:28°C avg high

Honolulu's September climate peaks at 28°C each afternoon before cooling to 24°C overnight. 12 daily sunshine hours and just 8 wet days mean the odds of a fine day are solidly in your favour. It is a reasonable time to visit, with a backup plan for the occasional shower.

28°C

Avg High

24°C

Avg Low

8 days

Rain Days

12h

Sunshine

78%

Humidity

Temperature in Honolulu in September

The narrow 4°C gap between daytime and overnight temperatures, characteristic of coastal cities with maritime moderation, means a single mid-layer works across the whole day. At 78% humidity, the 28°C daytime high feels 2-4°C warmer in practice: quick-dry fabrics and shade-seeking between noon and 3pm are the sensible response. UV index averages 6 this month, classed as moderate. Sunscreen is a sensible precaution for extended outdoor time, particularly at midday. Wind averages 22 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 82°F average high, 75°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).

Temperature in September

Monthly Precipitation (mm)

What to Wear in Honolulu in September

Morning24°CBefore the day warms up
Afternoon28°CPeak daytime temperature
Evening27°CAfter sunset cools down

Packing for Honolulu in September means dressing for 28°C days and 24°C evenings. A light cotton tee with a casual overshirt works well at 28°C, the overshirt doubles as a layer for air-conditioned venues. Evening temperatures settle at 24°C, a modest 4°C drop that a light cardigan or denim jacket covers. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues. At 78% average humidity, quick-dry synthetic or bamboo fabrics dry overnight and stay comfortable longer than cotton.

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Local tip: Layers are more practical than a single heavy garment in Honolulu. The day-to-evening temperature shift rewards packing a versatile mid-layer you can add or remove as conditions change.

Events in Honolulu in September

September has no major festivals or public holidays in Honolulu, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.

What to Pack for Honolulu in September

Based on 28°C average highs and 8 rainy days

  • Light layers for morning and evening
  • Breathable T-shirts and comfortable trousers
  • UV-protective sunglasses
  • Quick-dry travel towel
  • Anti-chafe balm for long walking days
  • Moisture-wicking synthetic fabrics for active days
  • SPF 30+ sunscreen
  • Comfortable walking shoes (a second pair lets the first air out overnight)
  • Universal travel adapter
  • Small day pack for city exploration
  • Reusable water bottle

Best Activities in Honolulu in September

  • Explore outdoor markets and street food stallsMid-morning (10am-12pm)At 28°C, the temperature is ideal for extended walking without overheating
  • Guided walking tour of the historic centreMorning or late afternoonComfortable temperatures allow several hours on foot without fatigue
  • Visit rooftop viewpoints and observation decksGolden hour (1 hour before sunset)Warm clear evenings provide exceptional visibility for panoramic photography
  • Day trip to the surrounding countryside or coastFull day (depart by 8am)September is reliably dry enough for rural day trips without weather risk
  • Afternoon in a world-class museum or galleryAfternoon (2-5pm)Pairs well with outdoor morning activities and provides a mid-day rest from sightseeing
  • Coffee-house or traditional cafe culture experienceMid-morning or post-lunchA cultural ritual in this region that rewards slow appreciation regardless of weather
  • Evening live music, theatre, or opera performanceEvening shows typically at 7-9pmConsistent evening temperatures make getting to and from evening venues comfortable
  • Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningSeptember brings distinct seasonal changes to public green spaces worth exploring
  • Seek out chilled local specialities: cold-brew tea, ice desserts, or chilled seafood at street-level stallsAny time; most atmospheric in evening marketsHot-weather street food culture peaks in September, with vendors setting up specifically for warm evenings

Why is Honolulu warm in September?

Honolulu's September climate is governed by the Inter-Tropical Convergence Zone (ITCZ), which draws moisture-laden trade winds across the region, producing the characteristic wet season rainfall of warm tropical cities. Daytime heat peaks around 28°C, moderated slightly by afternoon convective showers. Overnight temperatures remain warm at 24°C because the humid air retains heat effectively. Climate data: Open-Meteo ERA5 (1991–2020).

Sunshine Hours

The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.

UV Index

A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate -- wear sunscreen. UV 6-7: High -- hat and SPF 30+ essential. UV 8-10: Very High -- limit midday exposure. UV 11+: Extreme -- seek shade between 10am-4pm.

Rain Days

A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.

Humidity

Relative humidity as a percentage. Below 40%: Dry -- skin and throat may feel parched. 40-60%: Comfortable -- ideal for most people. 60-80%: Sticky -- light, breathable fabrics recommended. Above 80%: Muggy -- heat feels more intense; quick-dry clothing is essential.

Frequently Asked Questions: Honolulu in September

In September, Honolulu experiences average highs of 28°C (82°F) and lows of 24°C (75°F). Expect around 8 rainy days and 12 hours of sunshine per day, with humidity averaging 78%. The 4°C gap between daytime and overnight temperatures is worth planning around: light layers work for most visitors during the day, but an overshirt or cardigan handles the cooler evenings. UV index averages 6, so sun protection is advisable on clear days.
Honolulu typically sees 8 rainy days in September, with total precipitation of around 22mm. Rain is moderate and manageable. Showers tend to pass quickly, and a light rain layer or foldable umbrella is sufficient protection for most days. For context, the driest month in Honolulu typically sees 4-6 fewer rain days than September.
Pack light layers, a light jacket for evenings, comfortable walking shoes, and sunscreen for Honolulu in September. Daytime temperatures of 28°C are pleasant, but the evening drop to 24°C means a jacket is essential if you plan to be out after dark. Rain is infrequent with only 8 wet days, so a light rain layer is optional. Comfortable walking shoes are a priority given the amount of ground most visitors cover.
Yes, September is an excellent time to visit Honolulu. With 12 daily sunshine hours and only 8 rainy days, conditions are ideal for sightseeing and outdoor activities. Temperatures averaging 28°C during the day are comfortable for long walks and outdoor dining. This is peak travel season, so booking accommodation in advance and arriving at popular attractions early in the morning helps avoid the busiest periods.
The average high temperature in Honolulu in September is 28°C (82°F), and the average low is 24°C (75°F). The mean daily temperature is approximately 26°C (79°F). The day-to-night range of 4°C is narrow, typical of coastal or maritime cities. These are 30-year climate normals based on the 1991 to 2020 reference period; individual years will vary, particularly in transitional months like spring and autumn.
The best month to visit Honolulu is generally May. May offers the most sunshine at 13 hours per day and only 8 rainy days. Average temperatures reach 26°C, making it comfortable for sightseeing, outdoor dining, and exploring the city. If your travel dates are flexible, planning your trip around May gives you the best chance of dry, bright weather.
September is shoulder or low season in Honolulu, meaning fewer tourists and generally lower prices than peak months. With 12 sunshine hours and 8 rainy days, the weather is less of a draw for mass tourism. This is an advantage for travellers who prefer a quieter, more relaxed experience with shorter queues and easier accommodation availability.
In September, Honolulu suits a range of activities thanks to mild temperatures around 28°C. Mix of indoor and outdoor activities works well given the moderate chance of rain. Top options include exploring historic neighbourhoods, visiting museums and galleries, local food markets, and day trips to surrounding areas. With 12 hours of sunshine, parks and waterfront walks are particularly enjoyable.

September ranks 6th sunniest of the year in Honolulu, with an average 12 daily sunshine hours. The driest months are January, February, and August. July is the hottest month (28°C avg high); February is the coolest (24°C). From here, temperatures fall 0°C into October. Compared to last month (August: 28°C high, 7 rain days), September is similarly warm and wetter. September sits in the middle of the annual sunshine ranking for Honolulu, offering a reasonable balance of good weather and manageable crowds.

Year-Round Climate

MonthHighLowRain DaysSunDetails
January25°C21°C710hView
February24°C21°C710hView
March25°C21°C911hView
April25°C22°C912hView
May26°C23°C813hView
June27°C24°C813hView
July28°C24°C813hView
August28°C24°C712hView
September28°C24°C812hView
October28°C24°C711hView
November26°C23°C710hView
December25°C22°C710hView

Other Months in Honolulu

JanFebMarAprMayJunJulAugSepOctNovDec

Plan Your Trip to Honolulu

Best Time to Visit Honolulu

Data Sources for Honolulu

Honolulu on WikipediaOpen-Meteo Climate APINOAA National CentersUK Met OfficeWMOGeoNames

Climate normals represent 30-year averages (1991-2020). Individual years may vary.