Yamaguchi

Planning a trip or just curious about the weather in Yamaguchi? Here you will find the most up-to-date information on weather conditions and forecasts to help you be prepared for any of nature's surprises.

The climate in Yamaguchi can be described as temperate with distinct subtropical features, characterized by four clearly defined seasons. The city enjoys warm, and at times hot and humid summers, and relatively mild, cool winters. Transitional seasons—spring and autumn—usually offer comfortable weather with gradual temperature changes.

Summer months, especially from June to August, are the warmest and most humid. Average temperatures in August reach 27.9°C, while maximums can rise above 30°C. Summer also marks the peak of precipitation, with July standing out for the highest number of rainy days (19 days) and rainfall volume (10 mm), indicating a distinct rainy season. In contrast, winters are drier and cooler, with average temperatures around 5-7°C in January and December, and less precipitation.

Spring brings a gradual warming starting in March, when the average temperature is around 10.6°C, reaching a comfortable 18.6°C in May. Autumn also delights with pleasant weather: September remains quite warm (averaging 24.3°C), but by November, the temperature drops to 13.2°C, and precipitation decreases noticeably, making this period an attractive time to visit.

The climate in Yamaguchi is characterized by noticeable seasonal temperature changes. Throughout the year, the average monthly temperature ranges from approximately 5.9°C in January to 27.9°C in August. The coldest month is typically January, when average lows drop to 3.1°C and highs rarely exceed 8.6°C. In contrast, August brings the hottest weather: average highs reach 31.0°C, and nights remain very warm with an average low of around 24.7°C.

Summer months in Yamaguchi, especially July and August, are quite hot and, judging by the number of rainy days, can be humid. The average daily temperature in June is around 22.3°C, rising to 26.5°C in July and reaching its peak at 27.9°C in August. Daytime highs during this period often exceed 25°C and can reach 30°C or higher. Winter, spanning December, January, and February, is relatively mild but cool. Average temperatures range from 5.9°C to 7.2°C. Nighttime frosts are possible, as minimum temperatures in January and February drop to 3.1°C - 3.5°C, but severe freezes are not typical.

Spring (March–May) and autumn (September–November) are transitional seasons with comfortable temperatures. In March, the average temperature is about 10.6°C, gradually rising to 18.6°C in May. In autumn, after the summer heat, the temperature in September stays around 24.3°C, decreasing to a pleasant 18.5°C in October and 13.2°C in November. Temperature fluctuations between day and night are present throughout the year, averaging 5–8°C. For example, in April, the difference between the average high (18.5°C) and low (10.6°C) is nearly 8°C, which is worth considering when planning outdoor activities.

The city of Yamaguchi experiences a distinct seasonality in its precipitation distribution throughout the year. The highest volume of rain occurs during the summer months, while late autumn and winter are characterized by significantly less precipitation.

The peak of the rainy season in Yamaguchi falls in the summer months, particularly in July, which is the wettest month of the year. July sees an average of 10 mm of precipitation, and rain occurs quite frequently—around 19 days per month. June and August are also relatively wet, with 8 mm of rainfall and 14–16 rainy days respectively. In these summer months, while precipitation is the most abundant for this region according to the data, it is spread over a large number of days, suggesting frequent but perhaps not always intense rain.

The driest months in Yamaguchi are November, December, and January, when the average monthly precipitation is just 2 mm. November also stands out for having the fewest rainy days—only about 7. October is also relatively dry with 3 mm of precipitation and approximately 8 rainy days. In the winter months, despite the cool weather, precipitation according to the data falls mainly as rain, given the low volume.

Despite the distinct wet and dry seasons, rain is possible in Yamaguchi throughout the year. Even in the transitional spring months, such as March, April, and May, the number of rainy days remains at 10–12, although the total precipitation during these periods (4–5 mm) is low. This suggests that light precipitation can occur with some regularity throughout most of the year.

When planning a trip to Yamaguchi, it's important to consider the variable weather throughout the year and pack accordingly. Layering is a key principle, as temperatures can fluctuate. Comfortable walking shoes are indispensable, as you will certainly want to explore the city. Winter months (December–February) are quite cool, with average temperatures around 6-7°C, so be sure to bring warm clothing: sweaters, fleeces, a warm jacket, a hat, scarf, and gloves. While winter precipitation is low, there are many rainy days, so a light waterproof jacket or umbrella will come in handy.

Spring (March–May) and autumn (September–November) are characterized by moderate temperatures, gradually rising in spring and falling in autumn. During these periods, you'll need a light jacket, jumpers, and t-shirts that can be layered. Summer in Yamaguchi (June–August) is warm and humid, with average temperatures reaching 26-28°C and potentially rising above 30°C in August. June and especially July are the rainiest months with frequent precipitation, so waterproof clothing and a reliable umbrella are absolutely essential. For the summer months, choose light, breathable fabrics made of natural fibers. Don't forget sunscreen and a hat for protection on clear days.