Last updated: February 24, 2025
In December, Portsmouth, United States experiences a distinct winter chill, with temperatures ranging from a brisk -19°C (-1°F) to a milder 15°C (59°F), culminating in an average of 1°C (34°F). This month also brings considerable precipitation, totaling 133 mm (5.2 in) over 10 days, contributing to the city's humid atmosphere with humidity levels reaching 81%. Residents and visitors alike can expect a mix of cold, damp days that emphasize the season's character while offering the charm of winter's touch.
In December, Portsmouth experiences a notable drop in temperatures, with minimums reaching a chilling -19°C (-1°F), indicative of winter's firm grip. The average temperature hovers around 1°C (34°F), while maximums struggle to reach a mild 15°C (59°F). This month marks a significant transition from the more temperate conditions of late fall, as the city emerges into its coldest season. While December brings a crisp bite to the air, the occasional milder day offers a brief respite, reminding residents of the fleeting warmth that will eventually return. As the year closes, Portsmouth's weather serves as a stark contrast to the warmth of summer, enveloping the city in a frosty embrace.
In December, Portsmouth experiences a notable increase in precipitation, with an average of 133 mm (5.2 in) over the month, marking it as one of the wetter times of the year. This trend follows the consistently high levels seen in the fall months, particularly October, which also recorded significant rainfall at 142 mm. December typically sees precipitation on about 10 days, indicating a steady, if somewhat less intense, rhythm of wet weather as the year draws to a close. Compared to the preceding months, the balance between rainfall and dry days shifts, suggesting that the city transitions into winter with a mix of chilly, moist conditions that wrap up the year. The precipitation pattern hints at the region's coastal climate influence, where winter storms can lead to substantial rainfall, reinforcing the season's wet characteristics.
In Portsmouth, United States, December sees a relative humidity of 81%, a slight increase from the more humid months of November, which sits at 84%. As we transition from the crisp fall air to the winter chill, humidity levels begin to stabilize, hovering around the 80% mark through the last month of the year. This pattern highlights a gradual decline from the spring and summer months, where humidity peaks at about 72% in May and June, and gradually drops to its lowest in July and August at 66%. By December, the air retains a comforting moisture, making it a notable month as the city braces for the cool weather ahead, demonstrating how seasonal changes significantly influence humidity levels throughout the year.
As winter settles in Portsmouth, December presents a low UV Index of 2, indicating minimal risk of harm from unprotected sun exposure. With a burn time of approximately 45 minutes, residents and visitors can enjoy outdoor activities with little concern for sun damage. This trend of lower UV levels reflects a gradual decline from the high and very high readings experienced during the summer months, such as June through August, when the UV Index was consistently in the 9 to 10 range with significantly shorter burn times. As the year wraps up, the shift to moderate and low UV levels in the latter months, including November’s UV Index of 3, highlights the seasonal variations in sun intensity. For more detailed information, visit Portsmouth UV Index.
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Portsmouth experiences a delightful decline in sunshine hours as December rolls in, with 176 hours of bright daylight illuminating the winter month. While this represents a dip from the sun-soaked peaks of summer, where July and August bask in over 330 hours of sunshine, it still captures a significant share of daylight compared to the early winter months. The transition from November's 193 hours showcases Portsmouth's gradual step into winter, yet the remaining daylight makes December a charming time to enjoy the crisp air and festive spirit. Overall, the trend reflects a seasonal ebb and flow, where month-to-month variations in sunlight paint a vivid picture of Portsmouth's dynamic climate throughout the year.
In Portsmouth, United States, the likelihood of sunny weather in December dips to 32%, reflecting one of the lower chances for sun amongst the year. This trend aligns with the cooler months, where the sunniest spell appears in March at 61%, followed by a noted peak in November with a 54% chance. The transition from fall to winter seems to bring about cloudier days, as December's sunny outlook mirrors the summer months of July and August, both also marked by a 32% chance. Interestingly, this suggests that as temperatures drop, Portsmouth residents can expect less sunshine, making December's landscape a bit gloomier compared to the more vibrant early spring days.
In Portsmouth, the month of December marks a consistent return to shorter days, with just 9 hours of daylight, mirroring the preceding months of November and January. As the year progresses from the sunniest days of June—boasting a generous 15 hours of daylight—there's a gradual decline in light availability, particularly noticeable as we transition from the vibrant spring and summer months into the quiet, reflective winter season. This cyclical pattern highlights the natural ebb and flow of daylight, with a steady increase from January’s 9 hours to a peak in June, before tapering back down as the year closes. December, imbued with a cozy charm, invites residents to relish in the serene intimacy of winter evenings while anticipating the gradual return of longer days ahead.
As December settles over Portsmouth, the winds maintain a steady rhythm with an average speed of 4.6 m/s (10 mph), mirroring the conditions of November. This consistency suggests a transition from the gustier months of spring and early fall, where speeds peaked during March at 5.2 m/s (12 mph). The gentle breezes of summer, however, lingered on as the warmest months showcased notably lower wind speeds, dropping to a calm 3.3 m/s (7 mph) in August. With winter approaching, these December winds offer a brisk backdrop perfect for cozying up indoors, while consistently hinting at the invigorating gales of the transitioning seasons. As the year wraps up, Portsmouth experiences a harmonious blend of tranquility and zest at this time of year, echoing the city's evolving relationship with the elements.
The weather in Portsmouth changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of December'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.
December and January both experience frigid temperatures, but January tends to be slightly colder overall. December has an average temperature of 1°C (34°F), with highs reaching 15°C (59°F), while January's average dips to -1°C (30°F). Precipitation is more pronounced in December, with 133 mm (5.2 in) over 10 days, compared to January's 79 mm (3.1 in) over 8 days. Additionally, humidity levels are slightly higher in January at 86% versus December's 81%. For more detailed weather information, you can check Portsmouth weather in January.
December and February share similar cold temperatures, with December averaging about 1°C (34°F) and February slightly cooler at 0°C (32°F). Both months experience minimum temperatures hovering around -19°C (-1°F) for December and -16°C (4°F) for February. In terms of maximum temperatures, December peaks at 15°C (59°F), while February can reach up to 17°C (64°F). Precipitation is relatively high in December, with 133 mm (5.2 in) over 10 days, compared to February's 98 mm (3.9 in) over 11 days. Humidity levels are also quite comparable, with December at 81% and February slightly higher at 84%. For more detailed insights on February, you can check out Portsmouth weather in February.
December and March exhibit noticeable differences in weather patterns, despite their proximity in the winter to spring transition. December tends to be colder, with average temperatures around 1°C (34°F) and a maximum of 15°C (59°F), while March sees a slight increase in warmth, averaging 2°C (36°F) with a maximum of 17°C (63°F). Precipitation levels are higher in December, measuring 133 mm (5.2 in) over 10 days, compared to 94 mm (3.7 in) in March, which also has precipitation over 10 days. Interestingly, humidity levels are quite similar between the two months, both hovering around 81-82%. For more detailed insights, you can explore Portsmouth weather in March.
December and April present stark contrasts in weather patterns. December typically experiences colder temperatures, with averages around 1°C (34°F) and occasional plunges to a minimum of -19°C (-1°F), while April sees a significant rise with average temperatures at 8°C (46°F) and maximums reaching up to 24°C (76°F). Precipitation is similar in both months, with December receiving 133 mm (5.2 in) over about 10 days, and April slightly higher at 143 mm (5.6 in) over 13 days. Humidity levels remain quite consistent, hovering around 80-81%. For those looking to understand what to expect during this transformative season, check out Portsmouth weather in April.
December and May offer starkly contrasting weather conditions. In December, temperatures can plummet to a minimum of -19°C (1°F), with an average temperature around 1°C (34°F) and occasional highs reaching 15°C (59°F). This month also sees significant precipitation, totaling 133 mm (5.2 in) over about 10 days and higher humidity at 81%. In contrast, May brings more moderate weather, with temperatures ranging from a minimum of 2°C (37°F) to a pleasant maximum of 27°C (82°F) and an average of 13°C (55°F). Although precipitation is slightly lower at 83 mm (3.3 in) over 11 days, the humidity decreases to 72%, making May feel much more comfortable. For a closer look at the weather specifics for May, you can refer to Portsmouth weather in May.
In December, temperatures can plummet to as low as -19°C (-1°F), with a chilly average of 1°C (34°F) and a maximum of 15°C (59°F). The month experiences significant precipitation of 133 mm (5.2 in) over approximately 10 days, accompanied by high humidity levels at 81%.
In contrast, June brings milder and more pleasant weather, with temperatures ranging from a minimum of 8°C (47°F) to a comfortable average of 18°C (65°F), reaching up to a warm 30°C (86°F). While precipitation is lower at 88 mm (3.5 in) across the same 10 days, humidity is also reduced to 72%.
For more detailed information, you can check out Portsmouth weather in June.
December and July present stark contrasts in weather patterns. December features much colder temperatures, with an average of 1°C (34°F) and occasional lows dropping to -19°C (-1°F), while July enjoys a much milder climate, averaging 22°C (71°F) and peaking at 31°C (88°F). In terms of precipitation, December sees slightly more at 133 mm (5.2 in) over 10 days compared to July's 123 mm (4.8 in) across 12 days. Additionally, December's humidity level is comparatively higher at 81%, which contributes to a chillier feel, while July's humidity is milder at 67%. For a closer look at conditions in July, you can visit Portsmouth weather in July.
December and August present stark contrasts in weather conditions. In December, temperatures can plummet as low as -19°C (-1°F), with an average hovering around 1°C (34°F) and a maximum of 15°C (59°F). This month also experiences higher humidity at 81% and greater precipitation, averaging 133 mm (5.2 in) over about 10 days.
Conversely, August offers a much warmer climate, with minimum temperatures of 13°C (55°F) and averages around 22°C (71°F). The maximum can reach up to 31°C (88°F), alongside lower humidity levels at 66%. Precipitation is also decreased, with only 71 mm (2.8 in) falling over 9 days. For more specific insights into temperatures and conditions during this summer month, you can visit Portsmouth weather in August.
When comparing the weather in December and September, we see a striking contrast in temperature and precipitation. December experiences much colder conditions, with minimum temperatures plummeting to -19°C (-1°F) and an average temperature around 1°C (34°F), while September enjoys a milder climate, with minimum temperatures of 7°C (46°F) and an average temperature of 18°C (65°F). Additionally, September is significantly drier, receiving 78 mm (3.1 in) of precipitation over 8 days compared to December's 133 mm (5.2 in) spread across 10 days, highlighting the wetter and chillier nature of late fall. Humidity levels also differ, with December averaging 81%, compared to September's 71%, adding to the crispness of the winter air. For more detailed insights on September weather, you can visit Portsmouth weather in September.
In December, temperatures plunge significantly, ranging from a minimum of -19°C (-1°F) to a maximum of 15°C (59°F), with an average of just 1°C (34°F). In contrast, October enjoys much milder weather, with a minimum of 1°C (34°F) and a comfortable maximum of 25°C (78°F), averaging 13°C (56°F). While both months experience considerable precipitation, December sees 133 mm (5.2 in) over approximately 10 days, compared to October's 142 mm (5.6 in) over 11 days. Humidity levels are relatively similar, with December at 81% and October at 78%. For more detailed insights into October's weather, you can visit Portsmouth weather in October.
December weather generally showcases colder temperatures compared to November. In December, the minimum temperature can drop to -19°C (-1°F), with an average of 1°C (34°F) and a maximum of 15°C (59°F). In contrast, November experiences milder conditions, with temperatures ranging from a minimum of -12°C (11°F) to a maximum of 20°C (69°F), leading to a higher average temperature of 6°C (43°F). Precipitation in December is slightly higher at 133 mm (5.2 in) over 10 days, compared to November's 108 mm (4.3 in) over 11 days. Humidity levels remain relatively close, with December at 81% and November at 84%. For more detailed insights into November's weather, you can visit Portsmouth weather in November.
As December rolls in, Portsmouth experiences a notable shift in weather patterns compared to the milder months of fall. While temperatures can vary significantly, with occasional mild days, the cold truly settles in with chilling lows that remind us winter is on the way. Precipitation, though present throughout the year, peaks this month as the city often grapples with grey skies and rain, heightening the overall humidity that can make chilly days feel even more biting. This combination of cool temperatures and increased chance of rain marks December as a transitional month, setting the stage for the colder depths of winter ahead. For a deeper understanding of how the weather in December fits into the broader trends, visit Portsmouth Climate.