Climate and Average Weather Year Round in Tsukuba Japan

In Tsukuba, the summers are short, warm, muggy, wet, and mostly cloudy and the winters are very cold, snowy, and mostly clear. Over the course of the year, the temperature typically varies from 25°F to 86°F and is rarely below 19°F or above 93°F.

Based on the tourism score, the best time of year to visit Tsukuba for warm-weather activities is from mid July to mid September.

The hot season lasts for 2.7 months, from June 25 to September 16, with an average daily high temperature above 78°F. The hottest month of the year in Tsukuba is August, with an average high of 85°F and low of 70°F.

The cold season lasts for 3.4 months, from December 3 to March 16, with an average daily high temperature below 54°F. The coldest month of the year in Tsukuba is January, with an average low of 26°F and high of 46°F.

In Tsukuba, 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 Tsukuba begins around October 4 and lasts for 5.9 months, ending around March 31.

The clearest month of the year in Tsukuba is December, during which on average the sky is clear, mostly clear, or partly cloudy 73% of the time.

The cloudier part of the year begins around March 31 and lasts for 6.1 months, ending around October 4.

The cloudiest month of the year in Tsukuba is June, during which on average the sky is overcast or mostly cloudy 67% 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 Tsukuba varies significantly throughout the year.

The wetter season lasts 6.8 months, from March 23 to October 15, with a greater than 30% chance of a given day being a wet day. The month with the most wet days in Tsukuba is June, with an average of 13.6 days with at least 0.04 inches of precipitation.

The drier season lasts 5.2 months, from October 15 to March 23. The month with the fewest wet days in Tsukuba is January, with an average of 4.2 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 Tsukuba is June, with an average of 13.6 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 50% 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. Tsukuba experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in Tsukuba. The month with the most rain in Tsukuba is September, with an average rainfall of 7.3 inches.

The month with the least rain in Tsukuba is January, with an average rainfall of 1.3 inches.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Tsukuba experiences significant seasonal variation in monthly snowfall.

The snowy period of the year lasts for 3.3 months, from December 17 to March 26, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Tsukuba is February, with an average snowfall of 4.1 inches.

The snowless period of the year lasts for 8.7 months, from March 26 to December 17. The least snow falls around August 3, with an average total accumulation of 0.0 inches.

The length of the day in Tsukuba varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 42 minutes of daylight; the longest day is June 21, with 14 hours, 38 minutes of daylight.

The earliest sunrise is at 4:21 AM on June 13, and the latest sunrise is 2 hours, 29 minutes later at 6:51 AM on January 8. The earliest sunset is at 4:24 PM on December 6, and the latest sunset is 2 hours, 36 minutes later at 7:01 PM on June 28.

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

Tsukuba experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.5 months, from June 10 to September 27, during which time the comfort level is muggy, oppressive, or miserable at least 23% of the time. The month with the most muggy days in Tsukuba is August, with 27.1 days that are muggy or worse.

The least muggy day of the year is February 13, 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 Tsukuba experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 4.6 months, from December 29 to May 18, with average wind speeds of more than 7.6 miles per hour. The windiest month of the year in Tsukuba is March, with an average hourly wind speed of 8.5 miles per hour.

The calmer time of year lasts for 7.4 months, from May 18 to December 29. The calmest month of the year in Tsukuba is July, with an average hourly wind speed of 6.7 miles per hour.

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

The wind is most often from the south for 2.1 months, from April 14 to June 16 and for 2.1 months, from June 24 to August 28, with a peak percentage of 47% on August 7. The wind is most often from the east for 1.1 weeks, from June 16 to June 24 and for 4.1 weeks, from August 28 to September 26, with a peak percentage of 40% on September 8. The wind is most often from the north for 6.6 months, from September 26 to April 14, with a peak percentage of 49% on January 1.

Tsukuba 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 2.5 months, from July 13 to September 28, with an average temperature above 74°F. The month of the year in Tsukuba with the warmest water is August, with an average temperature of 78°F.

The time of year with cooler water lasts for 3.9 months, from December 26 to April 23, with an average temperature below 60°F. The month of the year in Tsukuba with the coolest water is February, with an average temperature of 56°F.

To characterize how pleasant the weather is in Tsukuba 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 Tsukuba for general outdoor tourist activities is from mid July to mid September, with a peak score in the third week of August.

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 Tsukuba for hot-weather activities is from late July to late August, 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 Tsukuba typically lasts for 7.2 months (220 days), from around April 6 to around November 12, rarely starting before March 21 or after April 24, and rarely ending before October 26 or after November 29.

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 Tsukuba should appear around April 8, only rarely appearing before March 28 or after April 18.

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 11 to August 28, with an average daily incident shortwave energy per square meter above 5.3 kWh. The brightest month of the year in Tsukuba is May, with an average of 5.9 kWh.

The darker period of the year lasts for 3.1 months, from November 2 to February 5, with an average daily incident shortwave energy per square meter below 3.2 kWh. The darkest month of the year in Tsukuba is December, with an average of 2.6 kWh.

For the purposes of this report, the geographical coordinates of Tsukuba are 36.200 deg latitude, 140.100 deg longitude, and 108 ft elevation.

The topography within 2 miles of Tsukuba contains large variations in elevation, with a maximum elevation change of 2,749 feet and an average elevation above sea level of 578 feet. Within 10 miles also contains large variations in elevation (2,808 feet). Within 50 miles contains large variations in elevation (5,879 feet).

The area within 2 miles of Tsukuba is covered by trees (60%) and cropland (38%), within 10 miles by cropland (62%) and trees (34%), and within 50 miles by cropland (33%) and trees (30%).