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Average Weather 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.

Climate Summary

very coldcoldcoolcomfortablewarmcoolcoldJanFebMarAprMayJunJulAugSepOctNovDec64%64%29%29%overcastclearprecipitation: 6.5 inprecipitation: 6.5 inmuggy: 96%muggy: 96%0%0%drydrytourism score: 6.7tourism score: 6.70.00.0
Click on each chart for more information.

Temperature

The warm season lasts for 2.6 months, from July 6 to September 24, with an average daily high temperature above 74°F. The hottest day of the year is August 11, with an average high of 82°F and low of 75°F.

The cool season lasts for 3.5 months, from December 9 to March 27, with an average daily high temperature below 51°F. The coldest day of the year is February 3, with an average low of 36°F and high of 43°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

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

Average Hourly Temperature

Average Hourly Temperature in Ryōtsu-minatoJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMvery coldcoldcoldcoolcoolwarmcomfortablevery cold
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Boyalık, Turkey (5,402 miles away) and Sürmene, Turkey (4,943 miles) are the far-away foreign places with temperatures most similar to Ryōtsu-minato (view comparison).

Clouds

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 3 and lasts for 4.2 months, ending around December 9. On October 27, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 64% of the time, and overcast or mostly cloudy 36% of the time.

The cloudier part of the year begins around December 9 and lasts for 7.8 months, ending around August 3. On January 20, the cloudiest day of the year, the sky is overcast or mostly cloudy 71% of the time, and clear, mostly clear, or partly cloudy 29% of the time.

Cloud Cover Categories

Cloud Cover Categories in Ryōtsu-minatoclearercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Oct 2764%Oct 2764%Jan 2029%Jan 2029%Aug 346%Aug 346%Dec 946%Dec 946%clearmostly cloudyovercastmostly clearpartly cloudy
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

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 28 to February 23, with a greater than 42% chance of a given day being a wet day. The chance of a wet day peaks at 60% on December 10.

The drier season lasts 4.1 months, from February 23 to June 28. The smallest chance of a wet day is 24% on June 2.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 60% on December 10.

Daily Chance of Precipitation

Daily Chance of Precipitation in Ryōtsu-minatowetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Dec 1060%Dec 1060%Jun 224%Jun 224%Jun 2842%Jun 2842%Feb 2342%Feb 2342%rainmixed
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

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 most rain falls during the 31 days centered around July 9, with an average total accumulation of 6.5 inches.

The least rain falls around May 27, with an average total accumulation of 3.0 inches.

Average Monthly Rainfall

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Sun

The length of the day in Ryōtsu-minato varies significantly over the course of the year. In 2018, the shortest day is December 22, with 9 hours, 31 minutes of daylight; the longest day is June 21, with 14 hours, 49 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight in Ryōtsu-minatoJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 7 minMar 2112 hr, 7 minMar 2114 hr, 49 minJun 2114 hr, 49 minJun 2112 hr, 11 minSep 2312 hr, 11 minSep 239 hr, 31 minDec 229 hr, 31 minDec 22nightnightday
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 4:22 AM on June 14, and the latest sunrise is 2 hours, 40 minutes later at 7:02 AM on January 6. 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 2018.

Sunrise & Sunset with Twilight

Sunrise & Sunset with Twilight in Ryōtsu-minatoJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 144:22 AMJun 144:22 AM7:13 PMJun 287:13 PMJun 28Dec 74:26 PMDec 74:26 PM7:02 AMJan 67:02 AMJan 6daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2018. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

Humidity

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 15 to September 26, during which time the comfort level is muggy, oppressive, or miserable at least 24% of the time. The muggiest day of the year is August 6, with muggy conditions 96% of the time.

The least muggy day of the year is December 6, when muggy conditions are essentially unheard of.

Humidity Comfort Levels

Humidity Comfort Levels in Ryōtsu-minatomuggyJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Dec 60%Dec 60%96%Aug 696%Aug 6Jun 1524%Jun 1524%Sep 2624%Sep 2624%miserablemiserabledrydryoppressiveoppressivehumidhumidcomfortablecomfortable
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

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 28 to March 28, with average wind speeds of more than 12.1 miles per hour. The windiest day of the year is January 18, with an average hourly wind speed of 17.5 miles per hour.

The calmer time of year lasts for 7.0 months, from March 28 to October 28. The calmest day of the year is July 29, with an average hourly wind speed of 6.7 miles per hour.

Average Wind Speed

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

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 8 to October 12, with a peak percentage of 37% on September 23. The wind is most often from the west for 9.9 months, from October 12 to August 8, with a peak percentage of 59% on January 1.

Wind Direction

Wind Direction in Ryōtsu-minatoWNWJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%westsouthnortheast
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

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 18 to October 4, with an average temperature above 73°F. The day of the year with the warmest water is August 20, with an average temperature of 79°F.

The time of year with cooler water lasts for 4.1 months, from January 4 to May 7, with an average temperature below 55°F. The day of the year with the coolest water is March 10, with an average temperature of 49°F.

Average Water Temperature

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Best Time of Year to Visit

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.

Tourism Score

Tourism Score in Ryōtsu-minatoJanFebMarAprMayJunJulAugSepOctNovDec02468106.76.70.00.06.56.55.35.3precipitationprecipitationcloudscloudstemperaturetemperaturetourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

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.

Beach/Pool Score

Beach/Pool Score in Ryōtsu-minatobest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.76.70.00.0precipitationprecipitationcloudscloudstemperaturetemperaturebeach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

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.

Growing Season

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 31, rarely starting after March 17, or ending before December 18.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season in Ryōtsu-minatogrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Feb 2050%Feb 2050%Dec 3150%Dec 3190%Mar 1790%Mar 1790%Dec 1890%Dec 1811%Jan 1611%Jan 16Aug 2100%Aug 2100%very coldcoldcoolcomfortablewarmhotfreezing
The percentage of time spent in various temperature bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The black line is the percentage chance that a given day is within the growing season.

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 24, only rarely appearing before April 15 or after May 3.

Growing Degree Days

Growing Degree Days in Ryōtsu-minatoJanFebMarAprMayJunJulAugSepOctNovDec0°F500°F1,000°F1,500°F2,000°F2,500°F3,000°F3,500°F4,000°FApr 2481°FApr 2481°FJun 29900°FJun 29900°FAug 51,800°FAug 51,800°FDec 313,848°FDec 313,848°F
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

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 19 to August 22, with an average daily incident shortwave energy per square meter above 5.4 kWh. The brightest day of the year is June 2, with an average of 6.4 kWh.

The darker period of the year lasts for 3.1 months, from November 11 to February 16, with an average daily incident shortwave energy per square meter below 2.5 kWh. The darkest day of the year is December 26, with an average of 1.5 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in Ryōtsu-minatobrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWhJun 26.4 kWhJun 26.4 kWhDec 261.5 kWhDec 261.5 kWhApr 195.4 kWhApr 195.4 kWhAug 225.4 kWhAug 225.4 kWhFeb 162.5 kWhFeb 162.5 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Ryōtsu-minato are 38.078 deg latitude, 138.439 deg longitude, and 36 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%).

Data Sources

This report illustrates the typical weather in Ryōtsu-minato, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There is only a single weather station, Niigata Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Ryōtsu-minato.

At a distance of 61 kilometers from Ryōtsu-minato, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.

The station records are corrected for the elevation difference between the station and Ryōtsu-minato according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.