January Weather in Northern Mariana Islands Northern Mariana Islands

Daily high temperatures are around 84°F, rarely falling below 81°F or exceeding 87°F.

Daily low temperatures are around 76°F, rarely falling below 74°F or exceeding 79°F.

For reference, on June 12, the hottest day of the year, temperatures in Northern Mariana Islands typically range from 79°F to 88°F, while on February 18, the coldest day of the year, they range from 76°F to 84°F.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on January. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

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The month of January in Northern Mariana Islands experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 49% throughout the month.

The clearest day of the month is January 12, with clear, mostly clear, or partly cloudy conditions 53% of the time.

For reference, on August 13, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 92%, while on February 18, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 53%.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Northern Mariana Islands, the chance of a wet day over the course of January is rapidly decreasing, starting the month at 17% and ending it at 10%.

For reference, the year's highest daily chance of a wet day is 62% on September 22, and its lowest chance is 3% on March 21.

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during January in Northern Mariana Islands is decreasing, starting the month at 1.7 inches, when it rarely exceeds 4.5 inches, and ending the month at 1.1 inches, when it rarely exceeds 2.9 inches.

Over the course of January in Northern Mariana Islands, the length of the day is essentially constant. The shortest day of the month is January 1, with 11 hours, 15 minutes of daylight and the longest day is January 31, with 11 hours, 28 minutes of daylight.

The earliest sunrise of the month in Northern Mariana Islands is 6:42 AM on January 1 and the latest sunrise is 4 minutes later at 6:47 AM on January 23.

The earliest sunset is 5:57 PM on January 1 and the latest sunset is 17 minutes later at 6:14 PM on January 31.

Daylight saving time is not observed in Northern Mariana Islands during 2024.

For reference, on June 20, the longest day of the year, the Sun rises at 5:47 AM and sets 13 hours, 2 minutes later, at 6:49 PM, while on December 21, the shortest day of the year, it rises at 6:38 AM and sets 11 hours, 14 minutes later, at 5:51 PM.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

The figure below presents a compact representation of key lunar data for January 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The chance that a given day will be muggy in Northern Mariana Islands is gradually decreasing during January, falling from 100% to 97% over the course of the month.

For reference, on April 30, the muggiest day of the year, there are muggy conditions 100% of the time, while on February 7, the least muggy day of the year, there are muggy conditions 96% of the time.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Northern Mariana Islands is essentially constant during January, remaining within 0.2 miles per hour of 16.9 miles per hour throughout.

For reference, on December 7, the windiest day of the year, the daily average wind speed is 17.4 miles per hour, while on September 7, the calmest day of the year, the daily average wind speed is 11.2 miles per hour.

The hourly average wind direction in Northern Mariana Islands throughout January is predominantly from the east, with a peak proportion of 90% on January 1.

Northern Mariana Islands is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average surface water temperature in Northern Mariana Islands is essentially constant during January, remaining around 82°F throughout.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

Temperatures in Northern Mariana Islands are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

The average accumulated growing degree days in Northern Mariana Islands are rapidly increasing during January, increasing by 883°F, from 31°F to 913°F, over the course of the month.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy in Northern Mariana Islands is essentially constant during January, remaining within 0.2 kWh of 5.3 kWh throughout.

For the purposes of this report, the geographical coordinates of Northern Mariana Islands are 15.214 deg latitude, 145.756 deg longitude, and 0 ft elevation.

The topography within 2 miles of Northern Mariana Islands is essentially flat, with a maximum elevation change of 0 feet and an average elevation above sea level of 0 feet. Within 10 miles is also essentially flat (0 feet). Within 50 miles is also essentially flat (0 feet).

The area within 2 miles of Northern Mariana Islands is covered by cropland (79%) and trees (14%), within 10 miles by water (89%), and within 50 miles by water (99%).