Climate and monthly weather forecast
Hawaii, USA

Hawaii, the oceanic American state, is tropical but encounters four different Köppen climate zones: tropical, arid, temperate, and polar based on altitude and topography on the constituent islands.
The entire state is an archipelago surrounded by water, which lies in Oceania, southwest of the continental United States in the central Pacific Ocean. Trade winds from the Pacific Ocean substantially influence the weather as they push towards the northeastern slopes of the Hawaiian Islands, where they move further upwards and produce significant rainfall on the windward side.

The eight main islands have varied microclimates such as tropical rainforest, arid desert, temperate, and alpine based on the region's elevation and its relative position, windward or leeward concerning the high mountains. The diverse terrain of high mountain peaks up to 4200 meters, valleys, ridges, and extensive slopes is responsible for wide-ranging weather conditions. The vast Pacific Ocean that surrounds Hawaii on all sides supplies large quantities of fresh sea air throughout the year and acts as a giant thermostat that does not allow the temperatures of the islands to reach the high levels typical of the tropics.
Hawaii's climate is characteristically tropical but with moderate temperatures and humidity due to the influence of north and eastern trade winds.

Hawaii is popular, around the year tourist destination with its vast coastline of roughly 750 miles, diverse landscape amid a backdrop of mountains, warm tropical climate, and abundant public beaches. However, the best time to visit Hawaii is from May to October in the dry season, particularly in May and June, as the summer temperatures are not extreme due to trade winds and the surrounding abundant waters. July to December sees a regular threat of thunderstorms, and hurricanes though not destructive, occur in this period.

Hawaii has comfortable temperatures and sunny days regularly during the winter. Nevertheless, the period from November to April during the wet season is prone to heavy rainfall and is the worst time to visit Hawaii compared to the rest of the year. The windward areas on the northern mountain slopes get ample rainfall, and the hurricane and storm season stretches until December.
Most of the tourist resorts are on leeward sides, which means less rain and cooler temperatures - hence, flights and accommodation tend to be costly from November to April.

Spring in Hawaii, which spans from March to May, is pleasantly warm. During this season, the temperatures generally range from 68°F (20°C) to 82°F (27.8°C). Rainfall is reduced, especially when compared to the wetter winter months. The trade winds offer a gentle, cooling effect, ensuring that humidity remains bearable. This combination of factors makes spring a delightful time for beach activities and exploration.

The summer months in Hawaii, from June to August, see average high temperatures peak at 84°F (28.9°C). Rarely do highs cross 90°F (32.2°C), and nighttime temperatures seldom fall below 70°F (21.1°C). This period is considered the dry season and receives minimal rainfall. The cooling influence of trade winds, combined with the tempering effect of the surrounding ocean waters, ensures that summer remains comfortable and not excessively hot.

September to November constitutes the autumn season in Hawaii. Temperatures during this period typically range from 67°F (19.4°C) to 83°F (28.3°C). As the region transitions from the dry to the wet season, there's an uptick in rainfall, especially in late autumn. However, the influence of the trade winds persists, providing relief from the increasing humidity. Despite the onset of the wetter season, many parts of the islands still offer clear, sunny days.

Winter in Hawaii, from December to February, is marked by temperatures ranging from 65°F (18.3°C) to 79°F (26.1°C). While these temperatures are mild for winter standards, the season witnesses the highest amount of rainfall. Snow is a rare but captivating sight, visible only at higher altitudes on peaks like Mauna Kea and Mauna Loa. Mount Waialeale on Kauai records an impressive annual rainfall of 460" (11684mm), making it one of the wettest places on Earth. Despite this, the leeward sides of the islands remain relatively dry, ensuring that visitors can still enjoy sunny spells amidst the showers.

January in Hawaii marks the middle of its winter season. During this month, temperatures typically range from 65°F (18.3°C) to 79°F (26.1°C). The cooler temperatures in January, compared to December or February, make it one of the chilliest months in Hawaii, although it's mild when juxtaposed with many other regions worldwide. In terms of precipitation, January is among the wetter months. Weather in January »

February continues the winter trend in Hawaii, with temperatures oscillating between 65°F (18.3°C) and 79°F (26.1°C). The warmth of the Hawaiian February stands in stark contrast to the winter cold of many other regions, yet it's considered one of the cooler months for the archipelago. Rainfall in February remains significant, aligning with the wetter patterns observed in January. Weather in February »

March signals the transition from Hawaii's winter to its spring, with temperatures ranging from 66°F (18.9°C) to 80°F (26.7°C). While this month sees a slight uptick in temperatures from February, it remains milder than the approaching warmer months. Rainfall in March starts to recede, especially in the latter half, yet remains appreciable. Weather in March »

April in Hawaii is a distinct herald of spring, with temperatures gently climbing between 68°F (20°C) to 82°F (27.8°C). This month witnesses a clearer departure from the cooler tones of winter, paving the way for the imminent warmth of the approaching summer. As April progresses, rainfall becomes notably sporadic. Weather in April »

May in Hawaii truly embraces the summer spirit. Temperatures during this month hover between 70°F (21.1°C) and 84°F (28.9°C), providing warmth without overwhelming heat. The ascension in temperature from April is palpable, making May one of the preferred months for sun-seekers. Precipitation sees a marked decrease in May, aligning with the onset of Hawaii's dry season. Weather in May »

June in Hawaii is a quintessential summer month, exuding warmth and vibrancy. The temperatures typically range from 72°F (22.2°C) to 86°F (30°C), making it one of the warmer months, yet still pleasant due to the moderating effects of the surrounding Pacific waters. The month of June witnesses further reduction in rainfall, placing it firmly within Hawaii's dry season. Weather in June »

July stands tall as one of the hottest months in Hawaii, with temperatures oscillating between 74°F (23.3°C) and 88°F (31.1°C). The islands are immersed in the zenith of summer, radiating with sunlit days and balmy nights. Rainfall in July is scant, in line with the ongoing dry season. Weather in July »

August in Hawaii continues the summer saga with its balmy embrace. Temperatures typically fluctuate between 74°F (23.3°C) and 89°F (31.7°C), possibly making it the warmest month of the year. Despite the potential for elevated warmth, the omnipresent trade winds and the vast Pacific Ocean ensure a temperate reprieve. In terms of precipitation, August largely mirrors July, retaining its place in the dry season. Weather in August »

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. Weather in September »

October in Hawaii marks a distinct shift towards the wet season. Temperatures begin their descent from summer highs, settling between 72°F (22.2°C) and 85°F (29.4°C). This drop in temperature is accompanied by a rise in humidity, adding a moist texture to the air. Rainfall becomes more pronounced in October. Weather in October »

November in Hawaii is characterized by a deeper plunge into the wet season, establishing itself as one of the rainiest months. The temperature spectrum narrows, with readings oscillating between 70°F (21.1°C) and 83°F (28.3°C). Weather in November »

Hawaii's December is a confluence of the wet season's peak and the gentle commencement of winter. Temperatures hover in a comfortable bracket, ranging from 68°F (20°C) to 81°F (27.2°C). The days are slightly shorter, and the chill in the evening air becomes more palpable, particularly in the higher altitudes. December witnesses substantial rainfall, with Mount Waialeale on Kauai continuing its legacy of recording impressive precipitation figures. Weather in December »