Climate and Average Weather Year Round in Ryōtsu-minato Japan

In Ryōtsu-minato, the summers are short, warm, oppressive, and mostly cloudy; the winters are very cold, windy, and partly cloudy; and it is wet year round. Over the course of the year, the temperature typically varies from 36°F to 82°F and is rarely below 31°F or above 87°F.

Based on the tourism score, the best times of year to visit Ryōtsu-minato for warm-weather activities are from late May to mid July and from early September to mid October.

The warm season lasts for 2.6 months, from July 5 to September 23, with an average daily high temperature above 74°F. The hottest month of the year in Ryōtsu-minato is August, with an average high of 82°F and low of 74°F.

The cool season lasts for 3.5 months, from December 8 to March 26, with an average daily high temperature below 51°F. The coldest month of the year in Ryōtsu-minato is February, with an average low of 36°F and high of 44°F.

In Ryōtsu-minato, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Ryōtsu-minato begins around August 2 and lasts for 4.2 months, ending around December 8.

The clearest month of the year in Ryōtsu-minato is October, during which on average the sky is clear, mostly clear, or partly cloudy 60% of the time.

The cloudier part of the year begins around December 8 and lasts for 7.8 months, ending around August 2.

The cloudiest month of the year in Ryōtsu-minato is January, during which on average the sky is overcast or mostly cloudy 69% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Ryōtsu-minato varies significantly throughout the year.

The wetter season lasts 7.9 months, from June 27 to February 23, with a greater than 42% chance of a given day being a wet day. The month with the most wet days in Ryōtsu-minato is December, with an average of 18.3 days with at least 0.04 inches of precipitation.

The drier season lasts 4.1 months, from February 23 to June 27. The month with the fewest wet days in Ryōtsu-minato is May, with an average of 8.3 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Ryōtsu-minato is December, with an average of 18.1 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 60% on December 9.

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Ryōtsu-minato experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year in Ryōtsu-minato. The month with the most rain in Ryōtsu-minato is July, with an average rainfall of 6.0 inches.

The month with the least rain in Ryōtsu-minato is March, with an average rainfall of 3.1 inches.

The length of the day in Ryōtsu-minato varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 31 minutes of daylight; the longest day is June 21, with 14 hours, 49 minutes of daylight.

The earliest sunrise is at 4:22 AM on June 13, and the latest sunrise is 2 hours, 40 minutes later at 7:02 AM on January 7. The earliest sunset is at 4:26 PM on December 7, and the latest sunset is 2 hours, 47 minutes later at 7:13 PM on June 28.

Daylight saving time (DST) is not observed in Ryōtsu-minato during 2024.

The figure below presents a compact representation of key lunar data for 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.

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.

Ryōtsu-minato experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.4 months, from June 14 to September 25, during which time the comfort level is muggy, oppressive, or miserable at least 24% of the time. The month with the most muggy days in Ryōtsu-minato is August, with 28.6 days that are muggy or worse.

The least muggy day of the year is February 28, when muggy conditions are essentially unheard of.

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 Ryōtsu-minato experiences extreme seasonal variation over the course of the year.

The windier part of the year lasts for 5.0 months, from October 27 to March 27, with average wind speeds of more than 12.1 miles per hour. The windiest month of the year in Ryōtsu-minato is January, with an average hourly wind speed of 17.3 miles per hour.

The calmer time of year lasts for 7.0 months, from March 27 to October 27. The calmest month of the year in Ryōtsu-minato is July, with an average hourly wind speed of 6.8 miles per hour.

The predominant average hourly wind direction in Ryōtsu-minato varies throughout the year.

The wind is most often from the north for 2.1 months, from August 7 to October 11, with a peak percentage of 37% on September 22. The wind is most often from the west for 9.9 months, from October 11 to August 7, with a peak percentage of 59% on January 1.

Ryōtsu-minato 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 water temperature experiences significant seasonal variation over the course of the year.

The time of year with warmer water lasts for 2.6 months, from July 17 to October 3, with an average temperature above 73°F. The month of the year in Ryōtsu-minato with the warmest water is August, with an average temperature of 78°F.

The time of year with cooler water lasts for 4.1 months, from January 4 to May 6, with an average temperature below 55°F. The month of the year in Ryōtsu-minato with the coolest water is March, with an average temperature of 49°F.

To characterize how pleasant the weather is in Ryōtsu-minato throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best times of year to visit Ryōtsu-minato for general outdoor tourist activities are from late May to mid July and from early September to mid October, with a peak score in the last week of September.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Ryōtsu-minato for hot-weather activities is from late July to early September, with a peak score in the second week of August.

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

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).

The growing season in Ryōtsu-minato typically lasts for 10 months (314 days), from around February 20 to around December 30, rarely starting after March 15, or ending before December 17.

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.

Based on growing degree days alone, the first spring blooms in Ryōtsu-minato should appear around April 23, only rarely appearing before April 14 or after May 2.

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 experiences significant seasonal variation over the course of the year.

The brighter period of the year lasts for 4.1 months, from April 18 to August 21, with an average daily incident shortwave energy per square meter above 5.4 kWh. The brightest month of the year in Ryōtsu-minato is June, with an average of 6.2 kWh.

The darker period of the year lasts for 3.2 months, from November 10 to February 16, with an average daily incident shortwave energy per square meter below 2.5 kWh. The darkest month of the year in Ryōtsu-minato is December, with an average of 1.6 kWh.

For the purposes of this report, the geographical coordinates of Ryōtsu-minato are 38.078 deg latitude, 138.439 deg longitude, and 13 ft elevation.

The topography within 2 miles of Ryōtsu-minato contains only modest variations in elevation, with a maximum elevation change of 308 feet and an average elevation above sea level of 27 feet. Within 10 miles contains only modest variations in elevation (3,783 feet). Within 50 miles also contains extreme variations in elevation (3,881 feet).

The area within 2 miles of Ryōtsu-minato is covered by water (70%), cropland (14%), and trees (11%), within 10 miles by trees (45%) and water (43%), and within 50 miles by water (90%).