Saipan is the capital of the United States Commonwealth of the Northern Mariana Islands, an arc-shaped archipelago located in the Pacific Ocean. Situated near the equator, the Northern Mariana Islands are considered the sunniest islands in Micronesia. In fact, Saipan in listed in the Guinness Book of Records for being the place with the most consistent temperature year round in the entire world.
Saipan has a tropical marine climate moderated by seasonal northeast trade winds. There is little seasonal temperature variation on Saipan. In fact, the temperature variation between day and night is more extreme that between seasons. Altitude also affects the temperature in Saipan, so it is much cooler in the mountainous regions than in the coastal areas.
With its consistent year round tropical climate, gorgeous beaches, and remarkable diving opportunities, Saipan is a popular tourist destination. Saipan’s location in the Pacific Ocean makes it easily accessible by plane. It’s a 45 minute plane ride from Guam, three hours from Japan, four hours from the Philippines, six hours from Australia, and 15 hours from California. The island is especially popular with tourists from China, Japan, and Korea.
Seasons in Saipan
Average year-round temperature in Saipan is 84°F (28.9°C) with an average humidity of 79%. Saipan does not have typical seasons per se, but the dry season runs from December to June and the rainy season from July to November. August sees the heaviest amount of rainfall throughout the year.
During the dry seasons, Saipan has been known to experience droughts due to insufficient rainfall. Saipan, as well as the rest of the Northern Mariana Islands, is situated about 600 miles (966 km) from a breeding area of cyclonic disturbances located in the western Pacific Ocean. As a result of this positioning, Saipan is considered to be at Weather Condition Four at all times. This means that a typhoon with sustained winds up to 60 MPH (KPH) can strike within 72 hours. These cyclonic disturbances can escalate quickly and can sometimes develop typhoon force winds up to 120 MPH (193 KPH) or more.
While the ambient humidity on Saipan averages between 67% and 97%, the dew point is frequently a better measure of comfort. Dew point relates to whether perspiration will evaporate from the skin which leaves a person feeling cooler. The dew point in Saipan ranges from 69°F (muggy) to 79°F (oppressive), which is typical for tropical and subtropical regions.
Saipan sees an average of around eight hours of visible sun a day in December. Given Saipan’s close proximately to the equator, Saipan does not experience much variation in sunrise and sunset. The shortest day of the year is December 21 with 11 hours and 14 minutes of daylight. The earliest sunrise Saipan sees is at 5:46 a.m. on June 3rd and the latest sunrise is at 6:47 a.m. on January 25th while the earliest sunset is 5:44 p.m. on November 23rd, and the latest sunset is 6:52 p.m. on July 9th.
Rainfall & Typhoon Season
Directly north of Guam, Saipan is located in the infamous “Typhoon Alley.” This positioning puts the island at an increased risk of typhoons and generally the island will experience at least one typhoon a year. Typhoon season lasts several months and begins in late August or early September. Flooding and vegetation damaged by extreme winds are common consequences of tropical storms.
In 2002, Rota, Saipan’s smaller sister island, was hit by a super typhoon dubbed Pongsona. The typhoon ravaged Rota’s largest village with sustained winds of 278 MPH (126 KMH) and with gusts up to 85 MPH (137 KPH). The typhoon left 200 families homeless and caused over $30 million in damages in addition to causing extensive beach erosion, destroying a fuel pier, and devastating crops in the area.
Luckily, very few typhoons have passed through Saipan in the last decade. La Niña can suppress the cyclonic disturbances that can lead to tropical typhoons in the Northern Mariana Islands. In addition to this, the islands have been blessed with mild weather from a fairly neutral Pacific Ocean. On the other hand, El Niño tends to have the opposite effect on tropical storms.
In addition to the threat of typhoons, Saipan regularly experiences light to heavy rainfall, as well as tropical thunderstorms. January is most likely to experience light rainfall, while heavy rain is most often falls during August with an annual rainfall of 75 to 90 inches. Unlike the distribution of mean annual rainfall, the distribution of short-period extreme rainfall from typhoons is not correlated with island topography. The greatest amount of rainfall during a single timeframe is caused by typhoons.
Best Time to Visit
Since Saipan enjoys the most stable climate in the world, the temperature variations generally don’t factor into decisions about when to visit Saipan. Most tourists choose to visit Saipan during the dry season (December to March) although some people say the ideal time to visit Saipan is when the flame trees are blooming (April to August). In fact, Saipan hosts an annual Flame Tree Festival which is usually held in late April to showcase the rich art and cultural heritage of the islands.
Swimming in Saipan
A comfortable water temperature for swimming is very much a personal preference, however, the ocean temperatures in July for Saipan are about 86°F (30°C), which should be comfortable for nearly anyone. At a temperature of 86°F, most people should be able to be comfortable swimming for extensive amounts of time without feeling cold.
The Northern Mariana Islands’ consistent, tropic temperatures and warm water make this an ideal spot for the snorkeling enthusiast or devoted scuba diver. Many visiting scuba divers opt to wear 3 mm wetsuits for comfort, but because the warm is so warm most locals only wear swim trunks and a rash guard or a t-shirt when diving. Any tourists visiting the island should take advantage of the snorkeling and diving opportunities presented by Saipan, including the famous Grotto.
Information for Tourists
Because of the tropical climate, tourists should bring warm weather clothing, including shorts, dresses, skirts, and sandals. Even the nighttime temperature drop would not necessitate throwing on a jacket. Visitors will probably also want to pack at least a swimsuit or two to take advantage of Saipan’s gorgeous beaches. Tourists should also be sure to wear plenty of sunscreen when they’re outside enjoying island life.
The temperature does remain stable and this can pose a small safety risk for those people susceptible to heat-related illnesses, including sunstroke, like children and the elderly. Fatigue can occur during periods of prolonged exposure or heightened activit. Drink plenty of fluids to stay hydrated and move to cooler, shady areas if you begin to feel affected by the heat.
Weather on the Other Islands & Guam
At the southern end of the Mariana archipelago is the unincorporated U.S. territory of Guam. Boosting a larger population than Saipan and a well-established military base, Guam also has a moderate, tropical climate with temperatures ranges from the low 70’s to the mid 80’s. The annual mean temperature is 81 degrees. The coolest and driest months are December through February and the warmest, wettest months are March through August.
Guam experiences an annual rainfall of 80 to 110 inches. Like Saipan, Guam is at risk for experiencing typhoons and is always at Weather Condition Four which means that a typhoon could strike within a 72-hour time-frame.