September weather forecast
Hawaii, USA

September in Hawaii signifies a gentle transition from the intense summer to the softer hues of autumn. The month witnesses temperatures ranging from 73°F (22.8°C) to 87°F (30.6°C). While the warmth of summer lingers, there's a subtle decrease in the highs compared to August.

September’s rainfall sees a slight uptick, signaling the onset of Hawaii's wetter season. Mount Waialeale on Kauai starts to register more frequent showers, a pattern that will continue intensifying in the succeeding months. Windward areas, with their verdant landscapes, receive more frequent drizzles, providing a refreshing contrast to the sun-parched leeward coasts, which still manage to enjoy ample sunny spells.

Regions of elevation, such as Mauna Kea and Mauna Loa, continue to boast clear, mesmerizing skies for a majority of the month. Stargazers can often capture the beauty of celestial events, with the cooler nights enhancing the overall experience.

When juxtaposed with August, September brings a milder touch to the climate. The threat from the Pacific hurricane season still looms, albeit diminishing as the month progresses. As September draws to a close, the Hawaiian archipelago readies itself for October, a month that traditionally sees more pronounced changes in weather patterns, especially in terms of rainfall.

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• Honolulu - September »
  In Honolulu in September, the average water temperature is 80.4°F (26.9°C). In Honolulu during September, the rain falls for 17.9 days and regularly aggregates up to 1.22" (31mm) of precipitation.
• Hilo - September »
  Hilo, during September nights, records a temperature marginally cooler than the daytime average, at a pleasant 70°F (21.1°C). In Hilo, in September, the average water temperature is 79.3°F (26.3°C).
• Kailua - September »
  With an average ocean temperature of 80.4°F (26.9°C), September is the month with the warmest seawater in Kailua. With an average ocean temperature of 80.4°F (26.9°C), September is the month with the warmest seawater in Kailua.
• Kaneohe - September »
  September is the month with the warmest seawater in Kaneohe with an average ocean temperature of 80.4°F (26.9°C). In Kaneohe during September, the rain falls for 14.5 days and regularly aggregates up to 1.1" (28mm) of precipitation.
• Kahului - September »
  Kahului's temperature records reveal September as the warmest month, marked by average highs of 79.9°F (26.6°C) and lows of 76.1°F (24.5°C). September, recording an average high temperature of 79.9°F (26.6°C) and a low temperature of 76.1°F (24.5°C), is Kahului's warmest month.
• Ewa Gentry - September »
  June through September, with an average maximum UV index of 7, are months with the highest UV index in Ewa Gentry, Hawaii. June through September, with an average maximum UV index of 7, are months with the highest UV index in Ewa Gentry, Hawaii.
• Kihei - September »
  The month with the warmest seawater in Kihei is September, with an average ocean temperature of 80.1°F (26.7°C). September is Kihei's warmest month, registering average high temperatures of 79.9°F (26.6°C) and lows of 76.1°F (24.5°C).
• Wahiawa - September »
  Shifting into September, Wahiawa records an average high-temperature of a still warm 82.4°F (28°C), presenting minor fluctuations compared to the previous month. The least humid month in Wahiawa is September, with an average relative humidity of 73%.
• Schofield Barracks - September »
  On the last day of September, in Schofield Barracks, sunrise is at 6:23 am and sunset at 6:20 pm HST. Schofield Barracks's warmest season falls during August and September, averaging a high-temperature of 87.1°F (30.6°C).
• Wailuku - September »
  Wailuku registers the highest average temperatures during the month of September, with peaks of 79.9°F (26.6°C) and lows of 76.1°F (24.5°C). On the first day of September in Wailuku, Hawaii, sunrise is at 6:10 am and sunset at 6:41 pm.