December Weather in Saint Helens, United States

Last updated: February 24, 2025

December weather in Saint Helens, United States, is characterized by a chilly atmosphere that brings a mix of temperatures, reaching a maximum of 15°C (59°F) and dipping to a minimum of -5°C (23°F). With an average temperature around 5°C (41°F), residents and visitors can expect a moist environment, as the month sees 224 mm (8.8 in) of precipitation spread over approximately 20 days. High humidity levels at 87% contribute to a crisp, wintry feel, making it a time for cozy gatherings and the beauty of the season's weather.

December Temperature in Saint Helens

In December, Saint Helens experiences a subtle shift towards cooler temperatures as winter sets in. With minimums dipping to around -5°C (23°F), the town often feels the bite of the cold, though the average temperature hovers at a brisk 5°C (41°F). The maximum temperatures are modestly warm for the season, reaching up to 15°C (59°F), offering some respite from the winter chill. Compared to the preceding months, where temperatures gradually declined from October’s highs, December establishes itself firmly in the heart of winter. This transitional month reflects a typical Northwest winter pattern, with crisp days and the potential for light snowfall, inviting both local residents and visitors to embrace the season's tranquility.

December Weather in Saint Helens: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Saint Helens, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec414045505762676963524540
Data source: Temperature data for Saint Helens 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.

December Precipitation in Saint Helens

December in Saint Helens ushers in a notable increase in precipitation, showcasing an impressive 224 mm (8.8 in) of rain over 20 days. This makes December the wettest month of the year, surpassing even the typically soggy November, which recorded 209 mm (8.2 in). The trend reveals a significant rise in both precipitation amount and the frequency of rainy days as the year comes to a close. This seasonal shift accentuates the region's characteristic winter weather, where a steady rhythm of rain creates a lush and vibrant landscape. As temperatures drop and the days grow shorter, the heightened precipitation during December reinforces the importance of preparing for the wet conditions that define this time of year.

December Precipitation Trends in Saint Helens

The chart displays monthly precipitation patterns in Saint Helens, with values for each month alongside December's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec205205163140736291190149209224
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Saint Helens

In Saint Helens, United States, December marks the continuation of the region's high humidity trend, with levels peaking at 87%—tying with November for the most humid month of the year. As the year progresses, humidity slowly decreases from 85% in January to its lowest point of 71% in September, reflecting a shift from the damp chill of winter to drier late summer months. However, as autumn approaches, humidity levels rebound, rising significantly back to 81% in October and remaining elevated through the end of the year. This pattern indicates that while summer brings a welcome respite from the winter's moisture, the return of increased humidity during the final months of the year keeps the air feeling lush and moist, a hallmark of Saint Helens' climate.

December Average Humidity in Saint Helens

This chart illustrates the average monthly humidity levels in Saint Helens, with December's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how December's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec85%84%85%83%83%84%82%74%71%81%87%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Saint Helens

In December, the UV Index in Saint Helens, United States, dips to 2, categorized as low, which means residents can enjoy outdoor activities with minimal risk of sunburn, requiring about 45 minutes of exposure to reach burn time. This marks a return to the more moderate UV conditions seen in earlier months, particularly when compared to the very high indices of late spring and summer, where burn times dropped to a mere 15 minutes. As winter approaches, the trend clearly illustrates a shift towards safer sun exposure, making December an ideal time for leisurely activities without the pressing need for extensive sun protection. For more insights, check out the detailed Saint Helens UV Index.

Maximum UV Index Levels in Saint Helens for December

The chart shows the monthly maximum UV Index (UVI) for Saint Helens in December, 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.
JanFebMarAprMayJunJulAugSepOctNovDec23569101087532
Data source: Saint Helens December 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.

December Sunshine in Saint Helens

As winter settles in, December in Saint Helens brings a softer glow of 115 hours of sunshine, marking a gradual decline as the year comes to a close. This fleeting light contrasts sharply with the sun-drenched heights of July, which boasts an impressive 374 hours. Notably, the year witnesses a steady increase in sunshine hours from the dreary 88 hours of January, peaking in the lush days of summer. By December, the days are shorter, reflecting a gentle yet predictable tapering off from the autumn brilliance of November. As this charming town embraces the cooler season, the warmth of early winter sunshine offers a brief, delightful reminder of the brighter months ahead.

Monthly Sunshine Duration in Saint Helens: December Highlighted

The December sunshine duration represents the total number of hours Saint Helens experiences direct sunlight during the month of December, excluding cloudy or obstructed periods. This chart compares the sunshine duration of December with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec88h123h195h229h282h318h374h335h268h211h136h115h
Data source: Saint Helens December Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Saint Helens During December

As the year draws to a close, December in Saint Helens sees a noticeable decline in sunny weather, with only a 12% chance of sunshine. This marks the lowest probability for sunlight compared to other months, continuing a downward trend that begins as early as October when the chance drops to 28%. November further compounds this trend, offering a mere 14% chance of clear skies. The months preceding December, particularly June and July, exhibit a vibrant contrast with their peaks of 61% and 73% respectively, reflecting the Pacific Northwest's seasonal shift from bright summer days to the winter gloom. Thus, planning for sunny outings in December may require some adjustment, as the chances of basking in sunlight dwindle to their annual nadir.

Percentage of Sunny Days in December in Saint Helens

The chart illustrates the percentage of sunny days in Saint Helens throughout the year, with December highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Saint Helens experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec15%15%35%53%38%61%73%55%49%28%14%12%
Data source: Saint Helens December chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Saint Helens in December

As December rolls in, Saint Helens, United States, experiences its shortest daylight hours of the year, with just 8 hours of sunlight. This gradual decline in daylight begins after the peak brightness of the summer months, where both June and July bask in a generous 15 hours of daylight. As the calendar turns from fall to winter, residents witness a significant decrease, reflective of the year's natural cycles. From January's 9 hours to November's 9 hours, the days remain on the shorter side, making December's twilight arrival feel even more pronounced. This pattern emphasizes the contrast between the bright, long days of summer and the cozy, shorter days of winter, inviting moments of reflection and warmth during the festive season.

Average Daylight Hours in Saint Helens for December

The chart illustrates the variation in daylight duration in Saint Helens throughout the year, with December highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 7m10h 23m11h 57m13h 34m14h 56m15h 38m15h 15m14h 1m12h 28m10h 51m9h 27m8h 43m
Data source: Saint Helens daylight hours, calculated by summing the hours between sunrise and sunset for each day.

December Winds in Saint Helens

As we embrace December in Saint Helens, the average wind speed settles at a gentle 2.5 m/s (6 mph), mirroring the consistent breezes of earlier winter months. This stability contrasts with the subtle fluctuations seen throughout the year; from the brisk July peaks of 2.7 m/s (6 mph) to the milder autumn, where November also recorded a lively 2.7 m/s. Notably, the warmer months tend to boast slightly higher averages, with summer bringing a refreshing 2.7 m/s in July, yet the overall trend showcases a harmonic rhythm of wind speeds that remains comfortable and predictable. December's winds, wrapping the year in a familiar embrace, signal the onset of winter while inviting tranquil walks by the river, framed by the stunning Oregon landscape.

Average December Wind Speed in Saint Helens

The chart displays monthly wind speed patterns in Saint Helens, with values for each month shown alongside December's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how December's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.52.52.22.12.52.22.72.42.22.62.72.5 m/s
Data source: Saint Helens December wind data, generated using information from the Copernicus Climate Change Service.

How December Weather in Saint Helens Compares to Other Months

The weather in Saint Helens 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 Saint Helens and find detailed weather information for every month.

December and January exhibit notable similarities and differences in weather patterns. Both months share an average temperature of around 5°C (41°F), but January typically sees colder minimum temperatures, dropping as low as -14°C (7°F), compared to December's minimum of -5°C (23°F). Precipitation remains significant in both months, with December receiving slightly more at 224 mm (8.8 in) over 20 days, while January sees 205 mm (8.1 in) across 17 days. Additionally, humidity levels are quite comparable, with December at 87% and January slightly lower at 85%. For more details on January weather in this region, check out Saint Helens weather in January.

December and February both exhibit chilly temperatures, with December typically being slightly warmer overall. In December, temperatures range from a minimum of -5°C (23°F) to a maximum of 15°C (59°F), while February experiences slightly lower extremes, with a minimum of -7°C (19°F) and a maximum of 17°C (62°F). Precipitation levels are relatively close, with December receiving 224 mm (8.8 in) and February 205 mm (8.1 in), both spread over roughly 20 days. Humidity is a bit higher in December at 87%, compared to February's 84%, making December feel particularly damp. For a detailed look at February's climate conditions, check out Saint Helens weather in February.

In December, the weather in Saint Helens is quite chilly, with temperatures ranging from a minimum of -5°C (23°F) to a maximum of 15°C (59°F) and an average of 5°C (41°F). The month is also characterized by significant precipitation, totaling 224 mm (8.8 in) over approximately 20 days, coupled with high humidity levels at 87%.

In contrast, March presents a milder climate, with temperatures that range from a minimum of -3°C (27°F) to a maximum of 22°C (73°F), averaging around 7°C (45°F). Although March experiences slightly less precipitation at 163 mm (6.4 in) over 18 days, the humidity remains relatively comparable at 85%. For more detailed insights into March's weather patterns, you can check Saint Helens weather in March.

The weather in December and April shows distinct differences, reflecting the transition from winter to spring. In December, temperatures range from a chilly -5°C (23°F) to a mild 15°C (59°F), with an average of around 5°C (41°F). This month experiences significant precipitation, totaling 224 mm (8.8 in) over 20 days, combined with high humidity levels at 87%. In contrast, April brings a more moderate climate, with temperatures ranging from -1°C (30°F) to a warm 29°C (85°F) and an average of 10°C (51°F). Precipitation is lower in April, at 140 mm (5.5 in), spread over 16 days, and humidity slightly decreases to 83%. For more details, you can visit Saint Helens weather in April.

December and May present notably different weather patterns. In December, temperatures can drop as low as -5°C (23°F), with an average of 5°C (41°F) and highs reaching only 15°C (59°F). The month is characterized by high humidity levels at 87% and significant precipitation, averaging 224 mm (8.8 in) over 20 days. In contrast, May offers milder temperatures, with a minimum of 3°C (37°F), an average of 14°C (57°F), and maximum temperatures soaring up to 32°C (90°F). Precipitation is also lighter in May, totaling 73 mm (2.9 in) over just 11 days, and humidity is slightly lower at 83%. For a closer look at the weather specifics, you can check out Saint Helens weather in May.

December and June present starkly contrasting weather conditions. In December, temperatures range from a chilly -5°C (23°F) to a milder high of 15°C (59°F), with an average of 5°C (41°F). This month is also characterized by significant precipitation, totaling 224 mm (8.8 in) over approximately 20 days, and a high humidity level of 87%. In contrast, June experiences much warmer temperatures, with a minimum of 6°C (43°F) and an average of 17°C (63°F), peaking at a scorching 45°C (113°F). Precipitation is considerably lower in June, amounting to just 62 mm (2.5 in) over 9 days, along with a slightly lower humidity of 83%. For more details about that month, check out Saint Helens weather in June.

December and July weather present a stark contrast in climate conditions. In December, temperatures range from a chilly -5°C (23°F) to a mild 15°C (59°F), with an average of 5°C (41°F). The month sees significant precipitation, averaging 224 mm (8.8 in) over about 20 days, contributing to a high humidity level of 87%. Conversely, July boasts much warmer temperatures, with a minimum of 8°C (46°F), an average of 20°C (68°F), and a maximum reaching up to a scorching 37°C (99°F). The summer month experiences minimal rainfall, only about 9 mm (0.3 in) over 2 days, leading to a lower humidity of 82%. This seasonal change highlights the variability of weather patterns throughout the year. For more details on the summer climate, check out Saint Helens weather in July.

December weather in Saint Helens is characterized by colder temperatures, with minimums reaching as low as -5°C (23°F) and averages around 5°C (41°F), while the maximum peaks at 15°C (59°F). The month experiences significant precipitation, totaling 224 mm (8.8 in) over approximately 20 days, accompanied by high humidity levels at 87%. In contrast, August offers much milder conditions, with minimum temperatures of 8°C (47°F) and an average of 20°C (69°F), soaring up to a maximum of 39°C (102°F). Precipitation is scant in August, with only 11 mm (0.4 in) recorded over just 2 days, and humidity is comparatively lower at 74%. For more detailed insights, visit Saint Helens weather in August.

When comparing the weather in December and September, it's clear that December is significantly colder and wetter. In December, temperatures range from a chilly minimum of -5°C (23°F) to a maximum of 15°C (59°F), with an average of 5°C (41°F). This month also sees a higher amount of precipitation, totaling 224 mm (8.8 in) over 20 days, and humidity levels are notably high at 87%. In contrast, September offers milder temperatures, with a minimum of 6°C (43°F), an average of 17°C (63°F), and a peak of 35°C (95°F). Precipitation is substantially lower in September, amounting to only 90 mm (3.6 in) over 9 days, accompanied by a more comfortable humidity level of 71%. For a closer look at September weather specifics, you can visit Saint Helens weather in September.

Comparing the weather in December and October reveals some notable differences. In December, temperatures are significantly cooler, with a minimum of -5°C (23°F) and an average of 5°C (41°F), whereas October enjoys milder conditions with temperatures ranging from a minimum of -2°C (29°F) to an average of 11°C (52°F). Additionally, December experiences more precipitation, totaling 224 mm (8.8 in) across 20 days, compared to October's 149 mm (5.9 in) over 13 days. Humidity is also higher in December at 87%, compared to 81% in October, making October feel slightly more comfortable. For more details on the weather during October, you can visit Saint Helens weather in October.

In December, temperatures tend to be slightly colder than in November, with minimums dipping to -5°C (23°F) compared to November's -3°C (27°F). The average temperature also drops to 5°C (41°F) in December, while November has a slightly higher average of 7°C (46°F). Precipitation is more frequent in December, occurring over 20 days and totaling 224 mm (8.8 in), which is a bit more than the 209 mm (8.2 in) experienced in November over 18 days. Despite these differences, both months maintain high humidity levels at 87%. For more detailed insights about November weather, you can check out Saint Helens weather in November.

Compare Saint Helens's Climate with Cities Worldwide

Conclusion: What to Expect From December Weather in Saint Helens

As December rolls in, Saint Helens experiences a notable shift in weather patterns, contrasting sharply with the milder months preceding it. While the temperatures can dip to a brisk -5°C, the average plunges to a rather chilly 5°C, setting a wintry tone for the month. Rainfall becomes a consistent companion, with approximately 20 days of precipitation contributing to a substantial 224 mm for the month, and humidity levels soar to 87%. This combination not only blankets the region in a damp chill but also creates a strikingly different atmosphere compared to the rest of the year. For a more in-depth look at the weather all year round, check out Saint Helens Climate.