December Weather in Cornwall, Canada

Last updated: April 22, 2025

December in Cornwall, Canada, presents a striking contrast of temperatures, with a maximum of 14°C (58°F) and a minimum plunging to -19°C (-3°F). The average temperature hovers around -2°C (29°F), inviting a chilly winter ambiance. With precipitation totaling 97 mm (3.8 in) over 13 days, residents can expect a mix of snow and rain, fostering a damp atmosphere with a humidity level of 84%. This blend of cold and moisture sets the stage for Cornwall's picturesque winter scenes, making it a unique time to experience the charm of this Canadian locale.

December Temperature in Cornwall

As December settles in Cornwall, Canada, the temperatures take a noticeable dip, marking the transition into winter. With a minimum of -19°C (-3°F) and an average of -2°C (29°F), the month is characterized by crisp and cold conditions, perfect for those who appreciate the beauty of the season's chill. The maximum temperature reaches a mild 14°C (58°F), offering brief respites from the colder extremes. This month mirrors the deepening winter trend observed since November, where temperatures dropped significantly from the previous months. As Cornwall embraces December, the landscape transforms into a winter wonderland, inviting residents and visitors alike to enjoy outdoor activities against a backdrop of frosty air and glistening snow.

December Weather in Cornwall: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Cornwall, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec232228394860676860503928
Data source: Temperature data for Cornwall 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 Cornwall

In December, Cornwall, Canada experiences a noteworthy precipitation average of 97 mm (3.8 in), marking a significant continuation of the wetter conditions established in November, where residents faced 135 mm (5.3 in). With 13 rainy days, December’s trend aligns closely with earlier months like June and September, which also saw similar rainfall totals, suggesting a consistent pattern of wet weather as winter sets in. This uptick in precipitation indicates that Cornwall transitions into a wetter climate phase during the latter part of the year, making December a month of notable dampness and chill, as the landscape prepares for the colder days ahead.

December Precipitation Trends in Cornwall

The chart displays monthly precipitation patterns in Cornwall, 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.
JanFebMarAprMayJunJulAugSepOctNovDec8193758588976873977713597
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Cornwall

In Cornwall, Canada, December marks the conclusion of a year characterized by consistently high humidity levels. With December averaging 84% humidity, it mirrors the conditions of January and February, creating a stable atmosphere as winter settles in. Throughout the year, humidity levels fluctuate slightly, peaking in the warmer months of July and August at 86% and 87% respectively. Interestingly, the transition into spring sees a modest rise, with March and April both reaching 86%. Overall, the data suggests that while humidity in Cornwall varies with the seasons, it remains predominantly elevated, offering a unique atmospheric quality that residents experience year-round.

December Average Humidity in Cornwall

This chart illustrates the average monthly humidity levels in Cornwall, 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.
JanFebMarAprMayJunJulAugSepOctNovDec84%84%86%86%85%82%86%87%85%85%85%84%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Cornwall

In December, Cornwall, Canada experiences a low UV Index of 2, indicating minimal risk of harm from unprotected sun exposure. With a burn time of 45 minutes, residents can enjoy outdoor activities without the urgent need for sunscreen. This month marks a significant drop from the peak UV levels seen in the summer, where indices reached as high as 10 in June, highlighting the seasonal trends in sun exposure. As the year winds down, the focus turns to protective measures, ensuring a balance between soaking up the winter sun and maintaining skin health. For more detailed insights into seasonal variations, visit Cornwall UV Index.

Maximum UV Index Levels in Cornwall for December

The chart shows the monthly maximum UV Index (UVI) for Cornwall 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.
JanFebMarAprMayJunJulAugSepOctNovDec2357810887532
Data source: Cornwall 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 Cornwall

In Cornwall, Canada, December marks the transition into winter, bringing a dip in daylight hours as the year draws to a close. With 123 hours of sunshine, this month not only highlights a significant drop from the sun-drenched days of summer, peaking at 351 hours in August, but it also reflects the broader trend of decreasing sunlight throughout the fall. As we move from the vibrant light of June and July, it becomes evident that Cornwall experiences a gradual shift toward the more subdued and cozy ambiance of winter. Despite the reduced sunshine, December offers a unique charm, inviting residents and visitors alike to embrace the reflective beauty of the season.

Monthly Sunshine Duration in Cornwall: December Highlighted

The December sunshine duration represents the total number of hours Cornwall 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.
JanFebMarAprMayJunJulAugSepOctNovDec98h170h228h243h295h329h341h351h271h220h143h123h
Data source: Cornwall December Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Cornwall During December

In December, Cornwall, Canada, sees a 29% chance of sunny weather, a slight uptick compared to the chillier months preceding it. While this percentage may seem modest, it reflects a trend in which the likelihood of sunshine begins to revive as the year winds down from the low points of January's 16% and February's 27%. As winter settles in, Cornwall transitions from the dreary days of early winter, but December still lags behind the more promising months of spring, such as April and May, which boast chances of sun ranging from 28% to 41%. Nevertheless, residents and visitors can still hold onto hope for occasional bright days amidst the season's cozy charm.

Percentage of Sunny Days in December in Cornwall

The chart illustrates the percentage of sunny days in Cornwall 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 Cornwall experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec16%27%45%28%41%42%27%44%42%34%34%29%
Data source: Cornwall December chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Cornwall in December

In Cornwall, Canada, December marks the shifting tides of daylight, with the sun gracing the land for just 8 hours a day. This reduction in daylight follows the gradual decline that begins in the summer months, where residents enjoyed 15 hours in June and July. As fall sets in, daylight dwindles to 10 hours in October and 9 hours in November, preparing for the shortest days of the year. January brings a slight reprieve, with daylight increasing once again, signaling the gradual return of longer days. This cyclical pattern of daylight not only defines the seasonal rhythm in Cornwall but also beautifully encapsulates the transition from the vibrant life of summer to the quiet introspection of winter.

Average Daylight Hours in Cornwall for December

The chart illustrates the variation in daylight duration in Cornwall throughout the year, with December highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 4m10h 20m11h 57m13h 35m14h 59m15h 42m15h 19m14h 4m12h 29m10h 51m9h 24m8h 39m
Data source: Cornwall daylight hours, calculated by summing the hours between sunrise and sunset for each day.

December Winds in Cornwall

As December sweeps into Cornwall, Canada, residents can expect the winds to pick up, with an average speed of 6.2 m/s (14 mph), marking a notable increase as the year comes to a close. This brisk wind follows a general trend observed throughout the months, where the wind speeds tend to rise steadily from the summer's lull. While July and August experience their calmest days with winds dipping below 5 m/s, the autumn months lead into a sharp uptick, especially in November, where winds reach 5.8 m/s (13 mph). This natural crescendo culminates in December, providing a refreshing chill that reinforces the season's arrival. The pattern suggests that as the year transitions from temperate to colder climates, the winds intensify, offering a vivid reminder of nature's changeability in this scenic region.

Average December Wind Speed in Cornwall

The chart displays monthly wind speed patterns in Cornwall, 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.
JanFebMarAprMayJunJulAugSepOctNovDec5.35.76.25.65.25.44.74.65.54.55.86.2 m/s
Data source: Cornwall December wind data, generated using information from the Copernicus Climate Change Service.

How December Weather in Cornwall Compares to Other Months

The weather in Cornwall 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 Cornwall and find detailed weather information for every month.

In comparing the weather between December and January, January tends to be slightly colder, with an average temperature of -5°C (23°F), compared to December's average of -2°C (29°F). While both months experience similar maximum temperatures of 14°C (58°F), January has a lower minimum temperature of -20°C (-3°F), making it the colder of the two. Precipitation in January is also somewhat reduced, with 81 mm (3.2 in) falling over 10 days, compared to December's 97 mm (3.8 in) over 13 days. Humidity levels remain consistent at 84% in both months. For more specific details, you can check out Cornwall weather in January.

When comparing the weather in December and February, both months exhibit similar humidity levels at around 84%. However, December generally enjoys slightly milder temperatures, with an average of -2°C (29°F) compared to February's colder average of -5°C (22°F). The minimum temperatures are also a touch higher in December, dipping to -19°C (-3°F) versus February's -20°C (-4°F). Precipitation is relatively consistent, with December receiving 97 mm (3.8 in) over 13 days and February experiencing 93 mm (3.7 in) across 12 days. For a detailed look at February’s weather, you can visit Cornwall weather in February.

In December, temperatures range from a minimum of -19°C (-3°F) to a maximum of 14°C (58°F), with an average of -2°C (29°F). The month sees significant precipitation, totaling 97 mm (3.8 in) across 13 days, and humidity levels at a high 84%. In contrast, March experiences similar minimum temperatures of -19°C (-2°F) but features a slightly lower maximum of 11°C (53°F), with an average of -2°C (28°F). Precipitation decreases to 75 mm (2.9 in) over the same number of days, and humidity remains marginally higher at 86%. For more insights, check out Cornwall weather in March.

December and April present contrasting weather experiences. In December, temperatures can plummet to a minimum of -19°C (-3°F), with an average chilling at -2°C (29°F) and a maximum reaching only 14°C (58°F). The month is characterized by frequent precipitation, totaling 97 mm (3.8 in) over 13 days, while the humidity remains high at 84%. In contrast, April brings a gradual warming trend, with minimum temperatures of -8°C (18°F), an average of 4°C (39°F), and a maximum of 18°C (65°F). Although precipitation is slightly less at 85 mm (3.4 in) over 12 days, humidity levels are comparable at 86%. For a detailed look at what to expect, check out Cornwall weather in April.

In December, the weather is significantly colder, with average temperatures hovering around -2°C (29°F) and dipping as low as -19°C (-3°F). This month experiences about 97 mm (3.8 in) of precipitation over 13 days, and the humidity is quite high at 84%, creating a chilly and damp atmosphere. In contrast, May brings a welcome warmth, with average temperatures increasing to 9°C (49°F) and reaching a maximum of 24°C (76°F). Although it has slightly less precipitation at 88 mm (3.5 in) over the same number of days, the humidity remains similarly high at 85%. To learn more about May's weather specifics, you can visit Cornwall weather in May.

December and June exhibit stark contrasts in weather. December experiences frigid temperatures, with lows plunging to -19°C (–3°F) and an average hovering around -2°C (29°F), while June enjoys milder conditions, starting from a minimum of 0°C (33°F) and peaking at an average of 15°C (60°F). Both months see similar precipitation levels of 97 mm (3.8 in), although December has slightly more rainy days at 13 compared to June’s 12. Humidity remains high in both months, with December at 84% and June at 82%. For a detailed look at the June weather patterns, you can visit Cornwall weather in June.

The weather in December contrasts sharply with that of July, highlighting the seasonal extremes. In December, temperatures can plummet to a minimum of -19°C (-3°F), with an average of -2°C (29°F) and a maximum of 14°C (58°F). This month also brings higher precipitation levels, accumulating 97 mm (3.8 in) over approximately 13 days, and maintaining high humidity at 84%. In contrast, July offers a much milder experience, where temperatures range from a minimum of 11°C (52°F) to an average of 20°C (67°F), peaking at 30°C (85°F). The summer month sees less rain, totaling around 68 mm (2.7 in) across 10 days, with humidity slightly higher at 86%. For a closer look at July weather specifics, you can visit Cornwall weather in July.

The weather in December contrasts sharply with that of August. In December, temperatures can plummet as low as -19°C (-3°F), with an average hovering around -2°C (29°F) and occasional peaks reaching 14°C (58°F). This month also sees significant precipitation, with about 97 mm (3.8 in) spread over 13 days and a high humidity level of 84%. In contrast, August experiences milder and more pleasant weather, with minimum temperatures starting at 11°C (51°F) and averaging 20°C (68°F), reaching a maximum of 30°C (86°F). Precipitation during August is relatively lower, at 73 mm (2.9 in) over 10 days, and the humidity slightly rises to 87%. For more details on Cornwall's weather in August, you can check out Cornwall weather in August.

December and September present striking contrasts in weather. While December temperatures can plunge as low as -19°C (-3°F) with an average high of just 14°C (58°F), September enjoys much milder conditions, with average lows around 3°C (38°F) and highs reaching a pleasant 27°C (82°F). Both months receive similar levels of precipitation—around 97 mm (3.8 in)—but December experiences rainfall over 13 days compared to September's 10 days. Humidity levels are quite similar, with December at 84% and September slightly higher at 85%. For a closer look at September weather specifics, visit Cornwall weather in September.

When comparing the weather of December and October, it's clear that December brings much colder temperatures, with a minimum of -19°C (-3°F) and an average of -2°C (29°F), while October enjoys milder conditions, featuring a minimum of -2°C (29°F) and a comfortable average of 10°C (50°F). Precipitation is slightly higher in December at 97 mm (3.8 in) over 13 days compared to October's 77 mm (3.0 in) over 11 days. Both months experience high humidity, but it remains consistent at around 84% in December and 85% in October. For more details on October weather in Cornwall, you can check Cornwall weather in October.

In comparing the weather between December and November, notable differences emerge in both temperature and precipitation. December experiences colder temperatures, with an average of -2°C (29°F) compared to November's more moderate average of 4°C (39°F). The maximum temperature in December is significantly lower at 14°C (58°F), whereas November sees a warm high of 20°C (68°F). Precipitation patterns also shift, with December receiving slightly less rain at 97 mm (3.8 in) over 13 days, compared to November's 135 mm (5.3 in) across 15 days. Humidity levels remain fairly constant, hovering around 84% in December and 85% in November. For more detailed information about November weather, check out Cornwall weather in November.

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Conclusion: What to Expect From December Weather in Cornwall

As December settles over Cornwall, the weather transforms into a more frigid landscape compared to the warmer months. With chilly temperatures and increased humidity, residents experience a notable shift, making it one of the colder times of the year. The frequent precipitation, often totaling around 97 mm, adds to the wintry atmosphere, resulting in a higher number of rainy days compared to previous months. This blend of cold and moisture creates a characteristic December chill that invites a cozy indoor retreat, contrasting sharply with the sunnier, milder days of summer. For more details on Cornwall's seasonal conditions, visit Cornwall Climate.