Just as the scenery of Hawaii can be varied, so too can the climate of the Hawaiian Islands vary from place to place.  Keeping in mind that many of the islands have desert, tropical rain forests as well as tundra regions, it is no surprise that the weather varies drastically depending on the topography. To best enjoy your vacation, you must understand some facts about the climate and weather patterns of the Hawaiian Islands so that you pack wisely.
At sea level, the island chain enjoys a fairly consistent temperature of between 75 to 85 degrees Fahrenheit (23 to 29 degrees Celsius) all year long. Despite this fairly warm and consistent coastal temperature, averages temperatures do decrease with altitude. Hawaii has the longest coastline in the United States but over 50% of the state has an elevation of over 2,000 feet. In fact, 10% of the land mass rises to an elevation of over 7,000 feet. While you may not think of snowfall in the tropics, Hawaii does get snowfall on many of the higher mountains throughout the winter and spring months.  It is common to find higher elevations, such as the Big Island’s largest mountain, Mauna Kea, sporting a pristine,  white, snow crest from late fall into spring. Depending on where you are going and what you may be doing, you may need warm clothes in addition to that bathing suit during your stay in Hawaii. If you intend to visit any of the higher elevations, packing long slacks and a jacket may be in order.
The islands enjoy the benefit of warm trade winds which blow from NE to ENE during much of the winter months. These winds bring cooler breezes from the north which often causes some precipitation in the islands. At other times of the year, these winds, known as “Kona winds” can flow in a southerly direction and bring hot, balmy air to the islands. Each island has a leeward side and also a windward side. The leeward side of the island is the part that faces South or West. This side of the island is generally hot, dry and sunny most of the time. Many of the best beaches and resorts are located on the leeward side of each island since sun worshippers and bathers can easily take advantage of these conditions.
The windward side of each island is the portion that faces North or East. The windward side often gets more precipitation due to the flow of the Kona winds. As a result of this increased rainfall, the windward side of each island offers a lush, green, tropical rain forest environment. When you visit the windward side of each island, you will find that it is more likely to be moderate, overcast and damp.  If you intend to spend time visiting the windward side of any of the islands, packing an umbrella and a light sweater for damper conditions is a must. Despite these generalities, weather patterns on the island are very localized so if you don’t like the weather where you are, drive to another part of the island and you will more than likely find a different weather pattern waiting for you.  
Interior lowland areas, such as are found on Oahu and on Maui can have the characteristics of both the leeward and windward lowland areas.  The interior lowland areas, especially those found on Oahu, can receive intense afternoon showers as a result of the heating of the land during the day. The benefit of the rapid and intense rain showers is an overall cooling of the mugginess that often precedes these showers. As a result, most people welcome the brief but intense showers that occur on these islands.

Taking time to look at the weather patterns for the major areas that you will be visiting will help you pack appropriately and be prepared for the types of activities available to you in the area. While you can always purchase needed items at local stores that you may have forgotten, remember that everything in Hawaiian stores has to be shipped in from outside the islands. As a result, it is often easier – and much cheaper – to plan well and bring the items you need with you for your Hawaiian vacation rather than try to buy them once you arrive in Hawaii.    

Most  people who are planning a vacation to the Hawaiian Islands for the first time rarely think to consult the weather forecast before taking off for their great Hawaiian destination. After all, Hawaii is a tropical paradise and well know that means hot sun, balmy temperatures and cool ocean breezes with only an occasional tropical shower.  This is definitely a misconception, however, as the Hawaiian islands are home to more variable weather patterns that you can imagine. While the overall temperature of the island chain is remarkably stable, with summer highs in the upper 80s F, (around 31 degrees C), and winter highs in the low to mid 70s (around 28 degrees C), these temperatures only apply to the lower lying coastal areas of most islands. If you plan to only sit by the pool or ocean side, you probably won’t need to pack warm clothing. However, some of the most gorgeous scenery on many of the islands lies above 2,000 feet so if you plan on exploring the higher altitudes of each island, be sure to pack sturdy shoes, long pants and even a jacket. In winter, some of the higher elevations such as Mauna Kea’s Observatory on the Big Island or Haleakala on the island of Maui can have snow on the ground and be quite bitterly cold.
Although the Hawaiian islands benefit from warm trade winds that keep them considerably less humid than other tropical island locations, the Hawaiian islands are susceptible to heavy rainfall during certain times of the year. Mt Waialeale on the island of Kauai, for example, is known as the “rainiest place on earth.”  This mountain area gets a staggering 460 inches (28 ft. 4 in., or 11.7 m) of rain annually. By checking the weather forecast before you travel you can make sure that you bring rain gear and/or an umbrella before venturing out to visit the various points on the island. While showers often are brief, they can be intense while they last. The cooling showers, especially mid-summer showers, often bring relief from the tropical afternoon heat so most Hawaiians welcome them. Another well know fact about the weather in the islands is that weather patterns are often very localized.  Don’t like the weather where you are?  Move to a different part of the island and you may well find a totally different weather pattern altogether.