Summer Weather in Iiyama JapanDaily high temperatures increase by 9°F, from 72°F to 80°F, rarely falling below 64°F or exceeding 90°F. The highest daily average high temperature is 84°F on August 7. Daily low temperatures increase by 9°F, from 58°F to 67°F, rarely falling below 52°F or exceeding 75°F. The highest daily average low temperature is 71°F on August 5. For reference, on August 6, the hottest day of the year, temperatures in Iiyama typically range from 71°F to 84°F, while on January 28, the coldest day of the year, they range from 25°F to 36°F. The figure below shows you a compact characterization of the hourly average summer temperatures. 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. Muttontown, United States (6,710 miles away) is the far-away foreign place with temperatures most similar to Iiyama (view comparison). CloudsThe summer in Iiyama experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 62% throughout the season. The highest chance of overcast or mostly cloudy conditions is 69% on July 2. The clearest day of the summer is August 12, with clear, mostly clear, or partly cloudy conditions 45% of the time. For reference, on July 2, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 69%, while on November 5, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 59%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Iiyama, the chance of a wet day over the course of the summer is very rapidly increasing, starting the season at 30% and ending it at 46%. For reference, the year's highest daily chance of a wet day is 56% on July 3, and its lowest chance is 29% on May 22. RainfallTo show variation within the season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day. The average sliding 31-day rainfall during the summer in Iiyama is very rapidly increasing, starting the season at 3.4 inches, when it rarely exceeds 5.3 inches or falls below 1.8 inches, and ending the season at 5.7 inches, when it rarely exceeds 9.0 inches or falls below 2.9 inches. The highest average 31-day accumulation is 6.5 inches on July 6. SunOver the course of the summer in Iiyama, the length of the day is rapidly decreasing. From the start to the end of the season, the length of the day decreases by 1 hour, 32 minutes, implying an average daily decrease of 1 minute, 0 seconds, and weekly decrease of 7 minutes, 3 seconds. The shortest day of the summer is August 31, with 13 hours, 0 minutes of daylight and the longest day is June 21, with 14 hours, 41 minutes of daylight. The earliest sunrise of the summer in Iiyama is 4:26 AM on June 13 and the latest sunrise is 50 minutes later at 5:16 AM on August 31. The latest sunset is 7:09 PM on June 28 and the earliest sunset is 53 minutes earlier at 6:16 PM on August 31. Daylight saving time is not observed in Iiyama during 2024. For reference, on June 20, the longest day of the year, the Sun rises at 4:27 AM and sets 14 hours, 41 minutes later, at 7:08 PM, while on December 21, the shortest day of the year, it rises at 6:55 AM and sets 9 hours, 38 minutes later, at 4:33 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. MoonThe figure below presents a compact representation of key lunar data for the summer of 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. HumidityWe 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 Iiyama is very rapidly increasing during the summer, rising from 2% to 59% over the course of the season. The highest chance of a muggy day during the summer is 87% on August 5. For reference, on August 5, the muggiest day of the year, there are muggy conditions 87% of the time, while on November 3, the least muggy day of the year, there are muggy conditions 0% of the time. WindThis 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 Iiyama is essentially constant during the summer, remaining within 0.3 miles per hour of 4.5 miles per hour throughout. For reference, on February 1, the windiest day of the year, the daily average wind speed is 9.6 miles per hour, while on August 3, the calmest day of the year, the daily average wind speed is 4.2 miles per hour. The lowest daily average wind speed during the summer is 4.2 miles per hour on August 3. The wind direction in Iiyama during the summer is predominantly out of the south from June 1 to June 23 and from July 25 to August 11, the west from June 23 to July 25, and the north from August 11 to August 31. Water TemperatureIiyama 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 Iiyama is very rapidly increasing during the summer, rising by 16°F, from 63°F to 79°F, over the course of the season. The highest average surface water temperature during the summer is 79°F on August 21. Growing SeasonDefinitions 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 Iiyama typically lasts for 7.8 months (240 days), from around March 30 to around November 25, rarely starting before March 14 or after April 15, and rarely ending before November 8 or after December 13. The summer in Iiyama is reliably fully 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. The average accumulated growing degree days in Iiyama are very rapidly increasing during the summer, increasing by 2,039°F, from 464°F to 2,504°F, over the course of the season. Solar EnergyThis 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 Iiyama is decreasing during the summer, falling by 1.2 kWh, from 6.2 kWh to 5.1 kWh, over the course of the season. The highest average daily incident shortwave solar energy during the summer is 6.2 kWh on June 1. TopographyFor the purposes of this report, the geographical coordinates of Iiyama are 36.850 deg latitude, 138.367 deg longitude, and 1,020 ft elevation. The topography within 2 miles of Iiyama contains very significant variations in elevation, with a maximum elevation change of 1,680 feet and an average elevation above sea level of 1,231 feet. Within 10 miles contains very significant variations in elevation (6,142 feet). Within 50 miles also contains extreme variations in elevation (9,967 feet). The area within 2 miles of Iiyama is covered by cropland (51%) and trees (39%), within 10 miles by trees (71%) and cropland (21%), and within 50 miles by trees (55%) and water (24%). Data SourcesThis report illustrates the typical weather in Iiyama, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. Temperature and Dew PointThere are 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Iiyama. For each station, the records are corrected for the elevation difference between that station and Iiyama according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations. The estimated value at Iiyama is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Iiyama and a given station. The stations contributing to this reconstruction are:
To get a sense of how much these sources agree with each other, you can view a comparison of Iiyama and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data. Other DataAll data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , 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 airports and weather stations are provided by AskGeo.com . Maps are © OpenStreetMap contributors. DisclaimerThe 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. Please review our full terms contained on our Terms of Service page. |