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April Weather in Seiyo, Japan

Last updated: August 23, 2025

In April, the average temperature in Seiyo, Japan hovers around 14°C (57°F). Expect temperatures to range from a chilly -1°C (31°F) to a warm 26°C (79°F). With around 140 mm (5.5 in) of precipitation spread over 10 days, you might want to bring an umbrella. The air is relatively humid too, with an average humidity of 76%.

April Temperature in Seiyo

In April in Seiyo, the average temperature is a mild 14°C (57°F). Maximums can reach a comfortable 26°C (79°F), while minimums can drop to a chilly -1°C (31°F). It's a great time to visit if you enjoy mild weather with some cool evenings!

April Weather in Seiyo: Daily Temperature Highs, Lows, and Averages

The chart illustrates April temperature patterns in Seiyo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Seiyo, April typically has an average temperature of 14°C (57°F), with highs reaching up to 26°C (79°F) and lows dropping to around -1°C (31°F).
JanFebMarAprMayJunJulAugSepOctNovDec394149576571778073645243
Data source: Temperature data for Seiyo generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

April Precipitation in Seiyo

In Seiyo in April, the total precipitation amount is 140 mm (5.5 in) spread over a period of 10 days.

April Precipitation Trends in Seiyo

The chart displays monthly precipitation patterns in Seiyo, with values for each month alongside April’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how April’s conditions compare to those of other months. In Seiyo, April typically receives around 140 mm (5.5 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec60971401401742364092192292136269
Data source: Precipitation data for April generated using information from the Copernicus Climate Change Service.
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April Humidity in Seiyo

In Seiyo in April humidity is 76%. With an average temperature of 14°C (57°F), this humidity feels like a warm blanket wrapped around you, creating a heavy atmosphere that can make outdoor activities feel sluggish and stifling, urging travelers to seek shade and refreshment more frequently.

April Average Humidity in Seiyo

This chart illustrates the average monthly humidity levels in Seiyo, with April’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In April, average humidity in Seiyo is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec74%70%70%76%83%86%91%88%85%82%79%77%
Data source: Humidity data for April generated using information from the Copernicus Climate Change Service.

April UV Index in Seiyo

In Seiyo in April, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Seiyo.

Maximum UV Index Levels in Seiyo for April

The chart shows the monthly maximum UV Index (UVI) for Seiyo in April, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In April, the maximum UV index in Seiyo typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec469101211121211864
Data source: Seiyo April UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How April Weather in Seiyo Compares to Other Months

Weather in Seiyo varies notably across the year, with each month offering distinct climate conditions. This page compares April’s weather to other months in Seiyo, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Seiyo, showing how April’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (40°F)60 mm (2.4 inches)74%moderate
February Weather5°C (41°F)97 mm (3.8 inches)70%high
March Weather9°C (49°F)140 mm (5.5 inches)70%very high
April Weather14°C (57°F)140 mm (5.5 inches)76%very high
May Weather18°C (65°F)174 mm (6.8 inches)82%extreme
June Weather22°C (71°F)236 mm (9.3 inches)86%extreme
July Weather25°C (78°F)409 mm (16.1 inches)91%extreme
August Weather27°C (80°F)219 mm (8.6 inches)88%extreme
September Weather23°C (74°F)229 mm (9.0 inches)85%extreme
October Weather18°C (64°F)213 mm (8.4 inches)82%very high
November Weather11°C (52°F)62 mm (2.4 inches)79%high
December Weather6°C (43°F)69 mm (2.7 inches)77%moderate

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