Last updated: March 17, 2025
In January, Portsmouth, United Kingdom experiences a cool maritime climate characterized by an average temperature of 7°C (44°F), with daily variations ranging from a max of 13°C (56°F) to a chilly minimum of 0°C (32°F). This month brings a significant amount of rainfall, totaling 68 mm (2.7 in) over approximately 11 days, contributing to the city's high humidity levels of 91%. As winter settles in, residents and visitors alike can expect a mix of brisk air and frequent rain showers, making for a typical yet dynamic British winter experience.
In January, Portsmouth experiences a chilly embrace as temperatures range from a minimum of 0°C (32°F) to a maximum of 13°C (56°F), settling at an average of 7°C (44°F). This month serves as a gateway to winter's grip, characterized by cool days and crisp nights. While the temperatures hover around the lower end of the spectrum, they begin to shift gently upwards as the month progresses, hinting at the arrival of spring. This trend sets the stage for February, which sees a slight dip with nighttime lows dropping to -3°C (28°F) before gradually rising again. The slow transition from colder to milder conditions throughout the early months showcases Portsmouth's unique maritime climate, where even the depths of winter carry a promise of warmth just around the corner.
In January, Portsmouth experiences an average precipitation of 68 mm (2.7 in) spread across approximately 11 days of rain. This marks the beginning of a wetter season, as the city transitions to heavier rainfall in the following months. February sees a slight increase to 75 mm (3.0 in), and March maintains a similar trend with 70 mm (2.7 in), demonstrating a consistent wet pattern early in the year. Notably, precipitation peaks in the autumn months, particularly in October and December, where averages soar to 117 mm (4.6 in) and 118 mm (4.7 in), respectively. This trend not only highlights Portsmouth’s generally moderate wet season but also indicates that residents can expect a significant increase in rainfall as winter progresses toward spring.
January in Portsmouth, United Kingdom, is characterized by a notably high humidity level of 91%, creating a distinct sense of dampness in the air. This trend of elevated humidity continues into February, which sees a slight dip to 89%, but remains significantly high. As the months progress toward spring, humidity gradually decreases, reaching 86% in March and 85% in April. The transition into summer marks a more pronounced drop, with May averaging 79% and July at a comfortable 71%. However, humidity levels begin to rise again toward autumn, peaking at 92% in both November and December, highlighting Portsmouth's characteristic maritime climate. Overall, January stands out but is part of a pattern where humidity fluctuates, driving the seasonal feel of this coastal city.
In January, Portsmouth experiences a UV Index of 2, categorized as low, which means the risk of harm from unprotected sun exposure is minimal, allowing for a comfortable burn time of 45 minutes. This trend of low UV exposure continues into February, maintaining the same index and exposure category. As spring approaches, the UV Index begins to rise, reaching 4 in March and 5 in April, both indicating moderate risk where burn times decrease to 30 minutes. By May, the UV levels peak significantly, soaring to 7 with a high exposure category, reducing burn time to just 25 minutes. The summer months bring even higher UV rays, with indices of 8 in both June and July, presenting a very high risk justifying a reduced burn time of 15 minutes. This trend continues into August, but begins to taper off slightly in September with a UV Index of 6, still categorized as high. As the year winds down, the index stabilizes at 4 in October, and finally drops back to a low of 2 in November before hitting a minimal 1 in December. This yearly cycle illustrates the importance of staying informed about UV levels throughout the seasons. For more details, check out the Portsmouth UV Index.
UV Risk Categories
In Portsmouth, the sunshine hours in January mark the beginning of a gradual ascent towards warmer months, recording just 105 hours of sunlight. As winter loosens its grip, February sees a slight increase to 146 hours, hinting at the promise of spring. The real transformation comes in March, where sunlight surges to 222 hours, energizing the city for the brighter days ahead. By April, the delightful transition is in full swing with 344 hours of sunshine, paving the way for May’s peak season, which boasts an impressive 410 hours. The golden rays continue through June and July, reaching 423 hours—the pinnacle of the year—before tapering off slightly in August. Despite the drop, late summer still enjoys 386 hours, while September's 320 hours signals the gradual slide into autumn. As the temperatures cool, sunlight remains at a respectable 252 hours in October, before waning once more in November and December, with 159 and 118 hours, respectively. This seasonal ebb and flow of sunlight paints a vibrant picture of Portsmouth’s climatic rhythm, transitioning from winter’s subdued glow to the brightness of summer’s peak.
In January, Portsmouth experiences a modest 21% chance of sunny weather, making it one of the cloudier months of the year. As the seasons shift, the likelihood of sunshine gradually rises, with February showing a slight increase to 26%. This upward trend continues into March, where the chances of sunny days reach 38%, hinting at the promise of spring just around the corner. By April, the sunny weather becomes more frequent, soaring to 58%, creating a stark contrast to the earlier months. Overall, these figures highlight the shifting dynamics of Portsmouth's weather, showcasing the potential for brighter days as winter gives way to spring.
In Portsmouth, United Kingdom, January marks the beginning of the year with a modest 8 hours of daylight, setting a slow-paced tone for winter days. As February approaches, daylight begins to creep up to 10 hours, signaling the first hints of spring. By March, the days continue to elongate, reaching 11 hours, and this progressive increase in daylight culminates in April with a vibrant 13 hours of sunshine. As the warmth of May arrives, residents enjoy even longer days of 15 hours, peaking in June with an impressive 16 hours of daylight. This summer bliss gradually wanes, tapering down to 15 hours in July and 14 hours in August, reminding us that the seasons are ever-changing. Autumn introduces a steady decline in daylight, with hours dropping to 12 in September and 10 in October before returning to 8 hours in the chill of November and December. Overall, Portsmouth's daylight patterns reflect a harmonious rhythm of seasons, where longer days herald the vibrancy of spring and summer, and shorter days invite a cozy retreat in the heart of winter.
In January, Portsmouth experiences an average wind speed of 6.4 m/s (14 mph), which sets a brisk tone for the month. This speed is slightly lower than the February average of 6.9 m/s (16 mph), indicating a shift towards fresher conditions as winter progresses. As spring approaches, the winds begin to calm, dropping to 5.8 m/s (13 mph) in March and further declining to 4.8 m/s (11 mph) by April. Notably, the summer months see these speeds decrease further, with June at a gentle 4.0 m/s (9 mph), reflecting more tranquil sea breezes. As the year unfolds, wind speeds gradually pick up again in the autumn months, reaching 6.2 m/s (14 mph) in October, before returning to 6.4 m/s (14 mph) in December, showcasing a seasonal rhythm that encapsulates the dynamic climate of Portsmouth.
The weather in Portsmouth changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of January's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Portsmouth and find detailed weather information for every month.
In January, temperatures in Portsmouth range from a minimum of 0°C (32°F) to a maximum of 13°C (56°F), with an average of 7°C (44°F). The month experiences about 68 mm (2.7 in) of precipitation over 11 days, and humidity levels are relatively high at 91%. In contrast, February sees slightly colder temperatures, with a minimum of -3°C (28°F) while still averaging 7°C (45°F) and maxing out at 13°C (55°F). Precipitation increases to 75 mm (3.0 in) over 12 days, and humidity stays close at 89%. Overall, February tends to be a bit wetter and cooler than January. For more details, check out Portsmouth weather in February.
In January, Portsmouth experiences chilly temperatures, with a minimum of 0°C (32°F) and an average of 7°C (44°F), while March sees slightly lower minimums of -3°C (28°F) but a similar average of 8°C (47°F). Both months receive comparable levels of precipitation, with January recording 68 mm (2.7 in) over 11 days, while March has slightly higher precipitation at 70 mm (2.7 in) across 13 days. January also has a higher humidity of 91%, compared to March's 86%, making January feel more damp and cold. For more detailed weather information, you can explore Portsmouth weather in March.
January and April present a notable shift in weather patterns. In January, temperatures range from a chilly minimum of 0°C (32°F) to a maximum of 13°C (56°F), with an average of 7°C (44°F). The month experiences considerably high humidity at 91% and sees around 68 mm (2.7 in) of precipitation over 11 days. In contrast, April offers a more temperate climate, with minimum temperatures around 1°C (34°F) and maximums peaking at 19°C (66°F), leading to a pleasant average of 10°C (50°F). Rainfall decreases significantly to 32 mm (1.3 in) across just 7 days, accompanied by slightly lower humidity at 85%. The transition from January's damp chill to April's refreshing warmth showcases the gradual shift towards spring. For a detailed look at April weather, you can check Portsmouth weather in April.
In January, Portsmouth experiences much cooler temperatures, with a minimum of 0°C (32°F) and an average of 7°C (44°F), reaching a maximum of 13°C (56°F). The month is characterized by high humidity at 91% and receives 68 mm (2.7 in) of precipitation over approximately 11 days. In contrast, May brings a significant warming trend, as temperatures rise to a minimum of 5°C (41°F), an average of 13°C (55°F), and a comfortable maximum of 22°C (71°F). Although it still sees precipitation on 11 days, the total drops to 56 mm (2.2 in), and humidity decreases to a more pleasant 79%. For more details on May's weather, visit Portsmouth weather in May.
In January, Portsmouth experiences cool temperatures, with a minimum of 0°C (32°F) and an average high of just 13°C (56°F). The month is marked by high humidity at 91% and receives about 68 mm (2.7 in) of precipitation over 11 days. In contrast, June brings much warmer weather, with temperatures ranging from a minimum of 9°C (49°F) to a pleasant maximum of 25°C (76°F). Although June sees slightly more precipitation at 73 mm (2.9 in), it enjoys fewer rainy days at 9, and the humidity drops to a comfortable 80%. This contrast highlights the transition from the cold, damp winter months to the warm, more temperate early summer. For more details, you can check Portsmouth weather in June.
January and July present stark contrasts in weather. In January, temperatures can drop to a chilly minimum of 0°C (32°F), with an average of 7°C (44°F) and a maximum reaching 13°C (56°F). The month is relatively wet, receiving about 68 mm (2.7 in) of precipitation over 11 days, accompanied by high humidity at 91%. In comparison, July offers much warmer temperatures, with a minimum of 12°C (53°F), an average of 18°C (65°F), and a maximum of 25°C (78°F). This summer month is drier, with only 58 mm (2.3 in) of rain over the same number of days, and the humidity lowers to 71%. For more detailed information, you can check Portsmouth weather in July.
In January, the weather is quite chilly, with temperatures ranging from a minimum of 0°C (32°F) to a maximum of 13°C (56°F) and an average of 7°C (44°F). The month experiences high humidity at 91%, along with 68 mm (2.7 in) of precipitation over 11 days. In contrast, August offers a much warmer climate, with temperatures varying from a minimum of 11°C (52°F) to a maximum of 26°C (80°F) and an average of 18°C (64°F). While August sees slightly more precipitation at 78 mm (3.1 in) over 12 days, the humidity drops to 76%, making the summer month feel more comfortable. For more details, you can check Portsmouth weather in August.
In comparing the weather between January and September, it's clear that September offers milder temperatures and less humidity. January temperatures range from a chilly 0°C (32°F) to a maximum of 13°C (56°F), with an average of 7°C (44°F) and a high humidity of 91%. In contrast, September boasts a minimum temperature of 8°C (47°F) and can reach up to 24°C (76°F), with an average of 16°C (61°F). Additionally, September experiences slightly less precipitation at 57 mm (2.2 in) over 10 days, compared to January’s 68 mm (2.7 in) over 11 days. For more detailed insights, you can explore Portsmouth weather in September.
When comparing the weather in January and October, notable differences emerge in both temperature and precipitation. January tends to be colder, with average temperatures ranging from a minimum of 0°C (32°F) to a maximum of 13°C (56°F), while October features milder conditions, with temperatures ranging from a minimum of 4°C (40°F) to a maximum of 20°C (68°F). In terms of precipitation, October sees a significant increase, with 117 mm (4.6 in) falling over 16 days compared to January's 68 mm (2.7 in) over 11 days. Despite the increased rainfall in October, the humidity levels remain relatively similar, with January at 91% and October at 90%. For more specific details about October weather in Portsmouth, you can visit Portsmouth weather in October.
In comparing the weather between January and November, notable differences emerge. January typically sees cooler temperatures, with a minimum of 0°C (32°F) and an average of 7°C (44°F), while November offers slightly warmer conditions, ranging from a minimum of 1°C (33°F) and an average of 10°C (50°F). Precipitation in November is generally higher, with 87 mm (3.4 in) of rain observed over 15 days, compared to January's 68 mm (2.7 in) over 11 days. Humidity levels are comparably high, with January at 91% and November at 92%. For more insights, refer to Portsmouth weather in November.
In December, the weather in Portsmouth tends to be slightly milder than in January, with average temperatures ranging from a minimum of 0°C (32°F) to a maximum of 14°C (57°F), compared to January's range of 0°C (32°F) to 13°C (56°F). December also sees more precipitation, with total rainfall reaching 118 mm (4.7 in) over 16 days, in contrast to January's 68 mm (2.7 in) across 11 days. The humidity remains relatively high in both months, with December at 92% and January at 91%. For more detailed information, visit Portsmouth weather in December.
As January unfolds in Portsmouth, the weather takes on a distinctly chilly and damp character, setting it apart from the milder months. With temperatures generally hovering around 7°C, January brings a notable drop in warmth, making it a time for cozy layers and warm drinks. The month is also marked by frequent rainfall, with approximately 11 days of precipitation, contributing to a high humidity level of 91%. This combination creates a fresh but often overcast atmosphere, offering a unique charm that highlights the resilience of both locals and visitors alike. For a deeper understanding of how these conditions fit into the broader context, explore Portsmouth Climate.