Summer Weather in Osaka Japan

Daily high temperatures increase by 9°F, from 79°F to 88°F, rarely falling below 72°F or exceeding 96°F. The highest daily average high temperature is 91°F on August 8.

Daily low temperatures increase by 11°F, from 64°F to 74°F, rarely falling below 58°F or exceeding 81°F. The highest daily average low temperature is 77°F on August 6.

For reference, on August 6, the hottest day of the year, temperatures in Osaka typically range from 77°F to 91°F, while on January 27, the coldest day of the year, they range from 34°F to 47°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.

Virginia Beach, United States (7,103 miles away) and Hashtpar, Iran (4,649 miles) are the far-away foreign places with temperatures most similar to Osaka (view comparison).

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The summer in Osaka experiences decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 60% to 50%. The highest chance of overcast or mostly cloudy conditions is 73% on July 1.

The clearest day of the summer is August 28, with clear, mostly clear, or partly cloudy conditions 50% of the time.

For reference, on July 1, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 73%, while on December 15, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 76%.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Osaka, the chance of a wet day over the course of the summer is rapidly increasing, starting the season at 34% and ending it at 41%.

For reference, the year's highest daily chance of a wet day is 53% on July 2, and its lowest chance is 19% on December 28.

Rainfall

To 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 Osaka is essentially constant, remaining about 6.5 inches throughout, and rarely exceeding 13.5 inches or falling below 1.4 inches.

The highest average 31-day accumulation is 8.3 inches on June 27. The lowest average 31-day accumulation is 4.8 inches on August 11.

Over the course of the summer in Osaka, 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, 24 minutes, implying an average daily decrease of 56 seconds, and weekly decrease of 6 minutes, 30 seconds.

The shortest day of the summer is August 31, with 12 hours, 56 minutes of daylight and the longest day is June 21, with 14 hours, 29 minutes of daylight.

The earliest sunrise of the summer in Osaka is 4:44 AM on June 12 and the latest sunrise is 46 minutes later at 5:30 AM on August 31.

The latest sunset is 7:15 PM on June 29 and the earliest sunset is 49 minutes earlier at 6:25 PM on August 31.

Daylight saving time is not observed in Osaka during 2024.

For reference, on June 20, the longest day of the year, the Sun rises at 4:45 AM and sets 14 hours, 29 minutes later, at 7:14 PM, while on December 21, the shortest day of the year, it rises at 7:01 AM and sets 9 hours, 50 minutes later, at 4:50 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 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.

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 Osaka is very rapidly increasing during the summer, rising from 12% to 80% over the course of the season.

The highest chance of a muggy day during the summer is 96% on August 4.

For reference, on August 4, the muggiest day of the year, there are muggy conditions 96% of the time, while on December 25, the least muggy day of the year, there are muggy conditions 0% 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 Osaka is essentially constant during the summer, remaining within 0.3 miles per hour of 6.3 miles per hour throughout.

For reference, on March 9, the windiest day of the year, the daily average wind speed is 9.4 miles per hour, while on August 2, the calmest day of the year, the daily average wind speed is 6.1 miles per hour.

The lowest daily average wind speed during the summer is 6.1 miles per hour on August 3.

The wind direction in Osaka during the summer is predominantly out of the south from June 1 to August 30 and the north from August 30 to August 31.

Osaka 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 Osaka is very rapidly increasing during the summer, rising by 12°F, from 67°F to 80°F, over the course of the season.

The highest average surface water temperature during the summer is 80°F on August 19.

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 Osaka typically lasts for 9.5 months (289 days), from around March 5 to around December 19, rarely starting before February 12 or after March 23, and rarely ending before December 1 or after January 6.

The summer in Osaka 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 Osaka are very rapidly increasing during the summer, increasing by 2,601°F, from 907°F to 3,508°F, over the course of the season.

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 Osaka is gradually decreasing during the summer, falling by 0.7 kWh, from 6.1 kWh to 5.4 kWh, over the course of the season.

For the purposes of this report, the geographical coordinates of Osaka are 34.694 deg latitude, 135.502 deg longitude, and 79 ft elevation.

The topography within 2 miles of Osaka contains only modest variations in elevation, with a maximum elevation change of 292 feet and an average elevation above sea level of 34 feet. Within 10 miles contains only modest variations in elevation (2,103 feet). Within 50 miles contains large variations in elevation (6,325 feet).

The area within 2 miles of Osaka is covered by grassland (81%), within 10 miles by grassland (39%) and water (22%), and within 50 miles by trees (56%) and water (22%).