Climate and Average Weather Year Round in Katsuura Japan

In Katsuura, the summers are short, warm, oppressive, and mostly cloudy; the winters are cold, windy, and mostly clear; and it is wet year round. Over the course of the year, the temperature typically varies from 41°F to 83°F and is rarely below 36°F or above 87°F.

Based on the beach/pool score, the best time of year to visit Katsuura for hot-weather activities is from late July to early September.

The warm season lasts for 2.6 months, from July 3 to September 21, with an average daily high temperature above 77°F. The hottest month of the year in Katsuura is August, with an average high of 83°F and low of 76°F.

The cool season lasts for 3.4 months, from December 9 to March 23, with an average daily high temperature below 57°F. The coldest month of the year in Katsuura is January, with an average low of 42°F and high of 52°F.

In Katsuura, 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 Katsuura begins around September 30 and lasts for 6.0 months, ending around March 30.

The clearest month of the year in Katsuura is December, during which on average the sky is clear, mostly clear, or partly cloudy 72% of the time.

The cloudier part of the year begins around March 30 and lasts for 6.0 months, ending around September 30.

The cloudiest month of the year in Katsuura is June, during which on average the sky is overcast or mostly cloudy 71% 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 Katsuura varies significantly throughout the year.

The wetter season lasts 7.8 months, from March 5 to October 31, with a greater than 32% chance of a given day being a wet day. The month with the most wet days in Katsuura is June, with an average of 13.4 days with at least 0.04 inches of precipitation.

The drier season lasts 4.2 months, from October 31 to March 5. The month with the fewest wet days in Katsuura is January, with an average of 5.9 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 Katsuura is June, with an average of 13.4 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 48% on June 23.

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. Katsuura experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in Katsuura. The month with the most rain in Katsuura is September, with an average rainfall of 7.6 inches.

The month with the least rain in Katsuura is January, with an average rainfall of 2.5 inches.

The length of the day in Katsuura varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 47 minutes of daylight; the longest day is June 21, with 14 hours, 32 minutes of daylight.

The earliest sunrise is at 4:23 AM on June 13, and the latest sunrise is 2 hours, 24 minutes later at 6:47 AM on January 8. The earliest sunset is at 4:26 PM on December 5, and the latest sunset is 2 hours, 31 minutes later at 6:57 PM on June 29.

Daylight saving time (DST) is not observed in Katsuura 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.

Katsuura experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 4.3 months, from May 30 to October 9, 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 Katsuura is August, with 29.8 days that are muggy or worse.

The month with the fewest muggy days in Katsuura is February, with 0.0 days that are muggy or worse.

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 Katsuura experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 7.7 months, from September 23 to May 12, with average wind speeds of more than 12.4 miles per hour. The windiest month of the year in Katsuura is February, with an average hourly wind speed of 14.4 miles per hour.

The calmer time of year lasts for 4.3 months, from May 12 to September 23. The calmest month of the year in Katsuura is August, with an average hourly wind speed of 10.4 miles per hour.

The predominant average hourly wind direction in Katsuura varies throughout the year.

The wind is most often from the south for 5.0 months, from April 10 to September 9, with a peak percentage of 51% on August 8. The wind is most often from the east for 3.4 weeks, from September 9 to October 3, with a peak percentage of 37% on September 28. The wind is most often from the north for 6.2 months, from October 3 to April 10, with a peak percentage of 51% on January 1.

Katsuura 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 some seasonal variation over the course of the year.

The time of year with warmer water lasts for 2.6 months, from July 16 to October 4, with an average temperature above 75°F. The month of the year in Katsuura with the warmest water is August, with an average temperature of 79°F.

The time of year with cooler water lasts for 3.8 months, from December 31 to April 25, with an average temperature below 64°F. The month of the year in Katsuura with the coolest water is February, with an average temperature of 60°F.

To characterize how pleasant the weather is in Katsuura 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 time of year to visit Katsuura for general outdoor tourist activities is from early September to early November, with a peak score in the second week of October.

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 Katsuura 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).

While it does not do so every year, freezing temperatures are seen in Katsuura over some winters. The day least likely to be in the growing season is January 16, with a 76% chance.

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 Katsuura should appear around March 7, only rarely appearing before February 20 or after March 26.

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 4.5 months, from April 15 to August 29, with an average daily incident shortwave energy per square meter above 5.4 kWh. The brightest month of the year in Katsuura is July, with an average of 5.9 kWh.

The darker period of the year lasts for 3.1 months, from October 30 to February 4, with an average daily incident shortwave energy per square meter below 3.3 kWh. The darkest month of the year in Katsuura is December, with an average of 2.6 kWh.

For the purposes of this report, the geographical coordinates of Katsuura are 35.146 deg latitude, 140.315 deg longitude, and 75 ft elevation.

The topography within 2 miles of Katsuura contains only modest variations in elevation, with a maximum elevation change of 486 feet and an average elevation above sea level of 86 feet. Within 10 miles contains only modest variations in elevation (1,204 feet). Within 50 miles also contains very significant variations in elevation (1,503 feet).

The area within 2 miles of Katsuura is covered by water (59%) and trees (28%), within 10 miles by water (68%) and trees (27%), and within 50 miles by water (80%).