Last updated: August 21, 2025
January in Karatsu, Japan, showcases a diverse climate, with temperatures ranging from a brisk -1°C (31°F) at night to a comfortable 18°C (64°F) during the day. The average temperature settles around 8°C (46°F), making layers essential for warmth. Rainfall is common, as 69 mm (2.7 in) of precipitation falls over 9 days, contributing to the region's refreshing humidity level of 73%. Whether exploring the stunning coastal scenery or enjoying local culture, visitors will experience a varied and engaging winter atmosphere.
In Karatsu, Japan, January showcases a noteworthy range of temperatures, with minimums dipping to -1°C (31°F) and maximums soaring up to 18°C (64°F), yielding an average of 8°C (46°F). This month marks the tail end of winter, as the chill gradually softens, evident in the modest rise in February where temperatures start at 0°C (32°F) and peak at 19°C (67°F). As spring approaches in March, the temperatures continue their upward trend, with minima settling at 5°C (41°F) and maxima reaching 20°C (68°F). Overall, the transition from the cold of January to the mildness of early spring is palpable, inviting a sense of renewal and warmth as the region prepares for more pleasant weather ahead.
In January, Karatsu experiences a modest precipitation total of 69 mm (2.7 in), spread over 9 rainy days, marking a relatively dry start to the year. This sets the stage for a gradual uptick in rainfall as winter transitions into spring. February sees a slight increase to 84 mm (3.3 in) over 11 days, while March marks a more significant rise in both intensity and frequency, with 136 mm (5.4 in) of rain falling across the same number of days. This upward trend continues into the spring months, peaking dramatically in July with an impressive 323 mm (12.7 in) over 18 days, highlighting the peak of the wet season. Overall, the data indicates a clear pattern where precipitation builds from a mild beginning to a robust rainy season, effectively shaping the local climate and landscape throughout the year.
In January, Karatsu, Japan experiences a moderate humidity level of 73%, setting the stage for the year ahead. As the month transitions into February, a slight decrease to 69% indicates a drier spell. However, humidity levels begin to rise again in March to 71%, foreshadowing the approaching spring. April brings a notable increase, peaking at 79%, and by May, humidity soars to 87%, marking the onset of the humid summer months. The peak is reached in July at an impressive 97%, creating a muggy atmosphere that continues into August with 94%. As autumn approaches, humidity gradually tapers off, starting at 84% in September and descending to 79% in October. November sees a slight drop to 75%, followed by another dip in December to 72%, wrapping up the year's humidity cycle on a relatively comfortable note. This trend showcases the dramatic shift from the drier beginnings of the year to the heavy humidity of summer, ultimately returning to a more balanced level by year-end.
In January, Karatsu experiences a moderate UV Index of 4, which translates to a burn time of 30 minutes for unprotected skin. This sets the stage for the beginning of the year, as sun exposure gradually intensifies. Moving into February, the UV Index rises to 6, marking a shift into the high exposure category with a reduced burn time of 25 minutes. As spring approaches, the UV levels escalate further, peaking in April and May with a staggering Index of 10 and 11, respectively, where burn times drop to just 10 minutes in the extreme range. This trend highlights the necessity for caution as the months progress, particularly from March through September, when UV exposure is at its most intense. For those residing in or visiting Karatsu, it's essential to stay informed about daily UV levels, especially as they fluctuate considerably throughout the year. For more details on UV levels, check out the Karatsu UV Index.
UV Risk Categories
January in Karatsu, Japan, welcomes the new year with an inviting 178 hours of sunshine, setting the stage for a gradual increase in daylight as winter melts into spring. As the months progress, February sees a charming uptick to 230 hours, giving way to a bright March that shines for 262 hours. This upward trend continues, peaking in May with an impressive 293 hours of sunshine, perfect for outdoor adventures. Following this crescendo, the days remain pleasantly sunlit throughout the summer, with August basking in 305 hours of golden rays. However, as autumn approaches, sunshine hours begin to recede, with September at 257 hours, marking a gentle decline that carries into the cooler months of October and November, where the days glow with 254 and 237 hours, respectively. Finally, December wraps up the year at 212 hours, reminding us that even in the depths of winter, Karatsu’s charm still shines bright.
In Karatsu, Japan, the likelihood of sunny weather in January stands at a modest 32%, marking it as one of the cooler months for sunshine. As the year progresses, February sees a notable increase to 44%, hinting at a gradual shift towards brighter days. March maintains a similar trend at 37%, while April and May stabilize around the low 40% range. However, the sunny disposition takes a dip in the summer months, with June dropping to 27% and July reaching a low of 21%. This decline in sunshine lingers into late summer and early fall, before a significant rebound in October, where the chances of sun are a striking 60%. Thus, while January may be less likely to offer clear skies, the promise of sunlight begins to rise as winter transitions into spring, only to ebb during the hotter months before peaking again in the fall.
In Karatsu, Japan, January marks the beginning of the year with a consistent 10 hours of daylight, a continuation from December's shorter days. As winter transitions into spring, February maintains the same daylight length, creating a steady backdrop for the mid-winter chill. With the arrival of March, the days grow slightly longer, shifting to 11 hours of daylight, while April and May enjoy a generous 13 hours each, inviting the vibrancy of spring to flourish. The momentum continues into June and July, where daylight peaks at 14 hours, providing ample time for outdoor adventures and summer activities. As summer wanes into August, daylight begins to taper, yet still boasts a respectable 13 hours. The gradual decline continues into the fall, with hours dropping to 12 in September and 11 in October, leading into November's 10 hours. Finally, December returns to a more subdued 9 hours, closing the year much as it began, highlighting the cyclical nature of daylight in this charming coastal town.
In Karatsu, Japan, January ushers in a crisp breeze with an average wind speed of 4.8 m/s (11 mph), matching February's gusty conditions. This steady wind pattern in the early months hints at a transition as spring approaches; by March, winds begin to taper off to 4.1 m/s (9 mph), continuing their gentle decline through April and May. The summer months bring calmer air, with June's winds dropping to a leisurely 2.7 m/s (6 mph), making way for the tranquil heat. Interestingly, the breeze picks up again in autumn, reaching 4.3 m/s (10 mph) in November, only to slightly ease back to 4.7 m/s (11 mph) by December. Overall, the data reveals a dynamic wind pattern in Karatsu, characterized by brisk beginnings and softer summer days, eventually returning to livelier gusts as the year draws to a close.
Weather in Karatsu varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Karatsu, focusing on differences in temperature, rainfall, humidity, and UV levels.
January and February exhibit relatively similar weather patterns, but with some notable differences. January boasts a minimum temperature of -1°C (31°F) and an average of 8°C (46°F), with a maximum reaching 18°C (64°F). In contrast, February starts slightly warmer, with a minimum of 0°C (31°F) and an average of 8°C (47°F), peaking at 19°C (67°F). Precipitation is more frequent in February, with 84 mm (3.3 in) over 11 days, compared to January's 69 mm (2.7 in) across 9 days. Additionally, February experiences slightly lower humidity at 69% compared to January’s 73%. For more detailed information on February weather, you can check Karatsu weather in February.
In January, the weather tends to be cooler, with average temperatures ranging from a minimum of -1°C (31°F) to a maximum of 18°C (64°F). The month experiences 69 mm (2.7 in) of precipitation over approximately 9 days, coupled with a humidity level of 73%. In contrast, March brings milder temperatures, with a minimum of 5°C (41°F) and a maximum of 20°C (68°F), averaging around 12°C (53°F). However, it also sees an increase in precipitation, totaling 136 mm (5.4 in) across 11 days, while maintaining a slightly lower humidity of 71%. For more detailed information, you can check Karatsu weather in March.
In January, the weather is notably cooler, with temperatures ranging from a minimum of -1°C (31°F) to a maximum of 18°C (64°F) and an average of 8°C (46°F). This month typically experiences 69 mm (2.7 in) of precipitation over about 9 days, accompanied by a humidity level of 73%. In contrast, April brings a significant warming trend, with temperatures rising to a minimum of 7°C (45°F) and a maximum of 24°C (75°F), averaging 15°C (59°F). However, this month sees an increase in precipitation, totaling 115 mm (4.5 in) over the same number of rainy days, while humidity also rises slightly to 79%. For a more detailed look at April weather patterns, you can check out Karatsu weather in April.
January weather in Karatsu is typically much cooler, with temperatures ranging from a low of -1°C (31°F) to a high of 18°C (64°F) and an average of 8°C (46°F). During this month, the region experiences about 69 mm (2.7 in) of precipitation over approximately 9 days, accompanied by a humidity level of 73%. In contrast, May sees a noticeable warming trend, with temperatures fluctuating between a minimum of 11°C (53°F) and a maximum of 27°C (80°F), averaging 19°C (67°F). Precipitation also increases to 153 mm (6.0 in) over roughly 11 days, along with higher humidity levels at 87%. This transition from the chill of January to the warmth of May highlights the significant seasonal shift. For more detailed insights, check out Karatsu weather in May.
January and June present starkly contrasting weather conditions. In January, the temperatures range from a chilly minimum of -1°C (31°F) to a comfortable maximum of 18°C (64°F), with an average of 8°C (46°F). Precipitation is relatively moderate, totaling 69 mm (2.7 in) over about 9 days, accompanied by a humidity level of 73%. In contrast, June brings significantly warmer weather, with temperatures starting at a minimum of 17°C (63°F) and reaching up to 29°C (84°F), averaging 22°C (73°F). The month also sees increased rainfall, accumulating 191 mm (7.5 in) across around 13 days, along with a higher humidity of 91%. These differences highlight the transition from winter to early summer conditions. For more details about the weather during this month, visit Karatsu weather in June.
In January, the weather is quite cool, with temperatures ranging from a minimum of -1°C (31°F) to a maximum of 18°C (64°F), and an average temperature of 8°C (46°F). The month experiences 69 mm (2.7 in) of precipitation over 9 days, accompanied by a humidity level of 73%. In stark contrast, July brings warmth and humidity, with temperatures ranging from a minimum of 20°C (68°F) to a maximum of 33°C (91°F) and an average temperature of 26°C (79°F). This month sees significantly more rain, totaling 323 mm (12.7 in) across 18 days, and a high humidity level of 97%. For more detailed insights into the weather specifics, you can check Karatsu weather in July.
January and August present striking contrasts in weather conditions. In January, temperatures range from a chilly -1°C (31°F) to a mild 18°C (64°F), with an average of 8°C (46°F). The month experiences around 69 mm (2.7 in) of precipitation over 9 days, contributing to the overall humidity of 73%. In stark contrast, August boasts a significantly warmer climate, with minimum temperatures starting at 21°C (70°F) and peaking at a sweltering 33°C (92°F), averaging 28°C (83°F). Precipitation in August is notably higher at 266 mm (10.5 in), spread over 13 days, resulting in a humidity level of 94%. For more specific details on weather conditions during August, you can check Karatsu weather in August.
The weather in January is markedly cooler and drier compared to September. In January, temperatures range from a chilly minimum of -1°C (31°F) to a pleasant average of 8°C (46°F) and can reach a maximum of 18°C (64°F). The month sees about 69 mm (2.7 in) of precipitation over approximately 9 days, with humidity levels at 73%. In contrast, September experiences much warmer temperatures, with a minimum of 19°C (66°F), an average of 25°C (77°F), and highs of up to 32°C (91°F). This month is significantly wetter, with 210 mm (8.3 in) of rain falling over 16 days and higher humidity at 84%. For more detailed information, you can check Karatsu weather in September.
In January, temperatures range from a chilly -1°C (31°F) at night to a mild 18°C (64°F) during the day, with an average of 8°C (46°F). The month sees around 69 mm (2.7 in) of precipitation over approximately 9 days, accompanied by a humidity level of 73%. In contrast, October offers much warmer temperatures, with nighttime lows of 13°C (56°F) and daytime highs reaching 29°C (84°F), averaging 20°C (69°F). Although October has higher precipitation at 112 mm (4.4 in) over about 10 days, the humidity slightly increases to 79%. For a detailed outlook on October weather, you can refer to Karatsu weather in October.
In January, the weather is considerably cooler, with average temperatures ranging from a minimum of -1°C (31°F) to a maximum of 18°C (64°F). The month sees about 69 mm (2.7 in) of precipitation over roughly 9 days, contributing to a humidity level of 73%. In contrast, November offers milder conditions, with temperatures ranging from a minimum of 7°C (45°F) to a maximum of 23°C (74°F). Rainfall is slightly less, at 53 mm (2.1 in) over 7 days, and humidity is slightly higher at 75%. For more information on November's weather, you can visit Karatsu weather in November.
In comparing the weather of January and December, January tends to be slightly cooler, with average temperatures ranging from a minimum of -1°C (31°F) to a maximum of 18°C (64°F), while December sees temperatures that are a bit warmer, with a minimum of 1°C (35°F) to a maximum of 21°C (71°F). Precipitation is slightly lower in January, recording 69 mm (2.7 in) compared to 81 mm (3.2 in) in December, although both months experience precipitation on about nine days. Humidity levels are quite similar, with January at 73% and December at 72%. For more details about the December weather, you can visit Karatsu weather in December.
January in Karatsu presents a unique blend of winter chill and mild temperatures, setting it apart from the more temperate months. With average highs around 8°C, the cold whispers of winter are felt, while occasional peaks can reach up to 18°C, offering brief respites from the brisk air. This month is also characterized by increased precipitation, with about 9 rainy days contributing to a notable humidity level of 73%. As the landscape transforms under the wintry skies, January becomes a month of quiet beauty and introspection in Karatsu. For a deeper insight into year-round conditions, visit Karatsu Climate.