September Weather in Sark, Guernsey

Last updated: August 21, 2025

September in Sark, Guernsey, brings a delightful mix of mild temperatures and occasional showers. With maximums reaching 22°C (72°F) and an average of 17°C (62°F), the weather is pleasantly warm, while minimums average about 12°C (54°F). The island experiences 71 mm (2.8 in) of precipitation over 10 days, contributing to a lush landscape. Humidity levels hover around 79%, making the air feel refreshing yet slightly damp. This month is an ideal time to explore Sark's natural beauty, with temperatures perfect for outdoor activities amid the enchanting scenery.

September Temperature in Sark

As September arrives in Sark, Guernsey, the warmth of summer lingers, offering a delightful transition into autumn. With temperatures ranging from a gentle 12°C (54°F) at night to a pleasant 22°C (72°F) during the day, the island enjoys an inviting climate perfect for outdoor activities. This month's average of 17°C (62°F) contrasts with the cooler figures of October ahead, marking a notable drop from the summer highs. September's mild conditions provide an ideal backdrop for exploring Sark's stunning landscapes before the cooler weather sets in, making it a favorite among visitors seeking the last vestiges of warmth before winter's approach.

September Weather in Sark: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Sark, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sark, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec484848505458626362595450
Data source: Temperature data for Sark 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.

September Precipitation in Sark

In September, Sark, Guernsey experiences a notable transition in weather, as the average precipitation rises to 71 mm (2.8 in) over 10 days of rainfall. This increase follows the relatively drier summer months of July and August, which recorded just 42 mm (1.7 in) and 57 mm (2.2 in) respectively. As autumn approaches, the precipitation levels not only set the stage for more frequent rain but also hint at the significantly wetter months ahead, such as October, which typically brings a sharp spike to 152 mm (6.0 in). This gradual rise in rainfall during September signals a shift from the warm, dry summer to the cooler, wetter conditions typical of the fall season, making it a pivotal month for Sark’s climate transition.

September Precipitation Trends in Sark

The chart displays monthly precipitation patterns in Sark, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Sark, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec988980355764425771152129177
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Sark

As September arrives in Sark, Guernsey, the humidity begins to shift, settling at 79%. This marks a subtle transition from the summer highs of 73% in August and a comfortable dip from the July low of 69%. Although September's levels are lower than the winter months of 89% in October, 92% in November, and December, they still reflect a gradual increase from the mild late summer. The overall trend showcases a steady rise in humidity as the seasons change, preparing the island for the crisp air of autumn while retaining some of the warmth of summer.

September Average Humidity in Sark

This chart illustrates the average monthly humidity levels in Sark, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Sark is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%89%86%85%80%80%69%73%79%89%92%92%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Sark

As September unfolds in Sark, Guernsey, residents and visitors can expect a UV Index of 6, signaling a high exposure category for sun seekers. This marks a slight decline from the peak summer months, yet the potential for sunburn remains significant, with a burn time of just 25 minutes. The UV Index shows a gradual downward trend from the extreme levels of 9 in June to 6 as autumn approaches, reminding us that while the intense summer sun wanes, caution is still paramount during outdoor activities. As you enjoy the beautiful early autumn days, don’t forget to stay protected! For more detailed information, check out the Sark UV Index.

Maximum UV Index Levels in Sark for September

The chart shows the monthly maximum UV Index (UVI) for Sark in September, 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. In September, the maximum UV index in Sark typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec234679876421
Data source: Sark September 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.

September Sunshine in Sark

As summer gently gives way to autumn, September in Sark, Guernsey continues to bask in a generous 338 hours of sunshine, marking a slight decline from the sun-soaked July and August months. This month reflects the gradual tapering of daylight as we transition from the long, bright days of summer, yet it still offers a robust amount of sunshine compared to earlier months, with a notable increase from the gloomy depths of winter, which sees a mere 107 hours in January. Following the peak summer hours, September's sunshine serves as a delightful reminder of the lingering warmth, providing ample opportunity to soak in the beauty of Sark's landscapes before the chill of October's 270 hours settles in. As the seasons shift, the charts reveal a clear trend: sunshine peaks in the summer and slowly recedes, but September’s still abundant sunlight invites both locals and visitors to enjoy the island’s charm a little longer.

Monthly Sunshine Duration in Sark: September Highlighted

The September sunshine duration represents the total number of hours Sark experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec107h163h238h359h414h416h436h396h338h270h181h130h
Data source: Sark September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Sark During September

September in Sark, Guernsey, offers a notable chance of sunny weather, with approximately 43% likelihood of enjoying sun-kissed days. This places September in a relatively balanced position, much like the warmer summer months of July and August, which boast chances of sunshine at 48% and 42%, respectively. Interestingly, September serves as a transition point; while the sunny probabilities start to decline as autumn approaches, it still maintains a robust chance of bright skies compared to the cooler months ahead, such as October and November. For those looking to bask in some late summer warmth, September provides a delightful window of opportunity.

Percentage of Sunny Days in September in Sark

The chart illustrates the percentage of sunny days in Sark throughout the year, with September 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 Sark experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec20%28%39%63%42%33%48%42%43%36%30%26%
Data source: Sark September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Sark in September

As September unfolds in Sark, Guernsey, the island experiences a gentle transition from the long, sunlit days of summer to the cozier, shorter days of autumn. With 12 hours of daylight, September marks a notable shift, providing a balance between the vibrant 16 hours of June and the 10 hours of October. This month serves as a beautiful bridge, showcasing nature's gradual transformation; the lush greens of summer begin to subtly fade, hinting at the rich hues of fall. The daylight duration in September is a reminder of the seasonal ebb and flow, inviting residents and visitors alike to embrace the lingering warmth while anticipating the cozy embrace of the cooler months ahead.

Average Daylight Hours in Sark for September

The chart illustrates the variation in daylight duration in Sark throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 41m10h 7m11h 55m13h 46m15h 21m16h 10m15h 44m14h 19m12h 32m10h 43m9h 5m8h 13m
Data source: Sark daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Sark

As summer transitions into autumn, the September winds in Sark, Guernsey offer a gentle breeze, averaging 5.9 m/s (13 mph). This subtle shift marks a continuation of the typically low wind speeds observed in the late summer months, following a relaxed June average of 4.5 m/s (10 mph) and a modest July speed of 5.8 m/s (13 mph). However, September's winds signal the onset of invigorating changes, hinting at the upcoming increase in speed with October's average climbing to 7.9 m/s (18 mph). The winds near the end of the year tend to pick up pace, with activities like sailing and outdoor exploration becoming increasingly appealing as the stronger autumn gales make their approach.

Average September Wind Speed in Sark

The chart displays monthly wind speed patterns in Sark, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec8.68.87.56.58.04.55.86.45.9 m/s7.97.49.3
Data source: Sark September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Sark Compares to Other Months

Weather in Sark varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Sark, focusing on differences in temperature, rainfall, humidity, and UV levels.

September and January present contrasting weather patterns. In September, temperatures range from a mild 12°C (54°F) at night to a comfortable 22°C (72°F) during the day, with an average of 17°C (62°F). This month experiences rainfall of 71 mm (2.8 in) over about 10 days, accompanied by a humidity level of 79%. In stark contrast, January sees much cooler temperatures, with a minimum of 2°C (37°F) and a maximum of only 13°C (57°F), averaging around 9°C (48°F). Additionally, January is wetter, receiving 98 mm (3.9 in) of precipitation over 15 days, and a higher humidity of 90%. For more detailed weather insights, you can check Sark weather in January.

In contrast to September's mild climate with temperatures ranging from a minimum of 12°C (54°F) to a maximum of 22°C (72°F), February experiences much cooler conditions, where temperatures typically peak at only 13°C (55°F). While September boasts an average temperature of 17°C (62°F) and relatively lower humidity at 79%, February sees a drop to an average of 9°C (48°F) along with higher humidity levels reaching 89%. Precipitation also differs between the two months; February is notably wetter, with 89 mm (3.5 in) falling over 16 days compared to September's 71 mm (2.8 in) across 10 days. For more specific insights on February weather, visit Sark weather in February.

September and March exhibit contrasting weather patterns, with September heralding the warmth of late summer, featuring average temperatures ranging from a mild 12°C (54°F) at night to a comfortable 22°C (72°F) during the day, along with 71 mm (2.8 in) of precipitation over about 10 days. In stark contrast, March is characterized by chillier conditions, with temperatures dipping as low as -1°C (31°F) and peaking at around 14°C (57°F), alongside higher precipitation levels totaling 80 mm (3.2 in) across approximately 15 days. Additionally, March experiences slightly higher humidity at 86%, compared to September’s 79%. For more details on the weather during this transitional month, visit Sark weather in March.

In comparing the weather of September and April, September tends to be significantly warmer, with average temperatures hovering around 17°C (62°F), while April's average temperature is much cooler at 10°C (50°F). September also experiences higher maximum temperatures, reaching up to 22°C (72°F), compared to April's maximum of only 15°C (60°F). Precipitation is more frequent in September, occurring on about 10 days with a total of 71 mm (2.8 in), whereas April sees less rainfall with only 35 mm (1.4 in) over 7 days. Additionally, humidity levels are slightly lower in September at 79%, while April has a higher humidity level of 84%. For more detailed information about April weather, you can check Sark weather in April.

In comparing the weather between September and May, September tends to be warmer with average temperatures reaching 17°C (62°F), while May averages only 12°C (54°F). The maximum temperature in September can reach 22°C (72°F), offering a pleasant early autumn experience, whereas May's highs are limited to 19°C (66°F). Precipitation is slightly higher in September, with 71 mm (2.8 in) over approximately 10 days, compared to May's 57 mm (2.2 in) over about 8 days. Both months feature similar humidity levels, around 79% in September and 80% in May. For more details on May weather, check out Sark weather in May.

In comparing the weather of September and June, both months experience relatively mild temperatures, but September tends to be slightly warmer. September boasts an average temperature of 17°C (62°F), with a maximum of 22°C (72°F), compared to June's average of 15°C (59°F) and a maximum of 21°C (70°F). Precipitation levels are somewhat similar, with September receiving 71 mm (2.8 in) and June totaling 64 mm (2.5 in), each having rain on about 10 days. Humidity is quite comparable as well, hovering around 79% in September and 80% in June. For a closer look at June's weather, visit Sark weather in June.

In September, the weather tends to be slightly cooler than in July, with minimum temperatures averaging around 12°C (54°F) compared to 14°C (58°F) in July. While both months show an average temperature of 17°C (62°F), September sees maximum temperatures reaching 22°C (72°F), similar to July's 23°C (73°F). However, September is notably wetter, with 71 mm (2.8 in) of precipitation over 10 days, compared to July's 42 mm (1.7 in) over just 8 days. Additionally, humidity levels are higher in September at 79%, compared to 69% in July. For more on how July weather typically looks, visit Sark weather in July.

In September, temperatures show a slight decrease compared to August, with minimums dipping from 14°C (57°F) in August to 12°C (54°F) in September. Both months have similar average temperatures of around 17°C (63°F), but September features slightly cooler maximums at 22°C (72°F) compared to August’s 23°C (73°F). Precipitation increases in September, with 71 mm (2.8 in) of rain over 10 days, compared to 57 mm (2.2 in) in August over the same number of days. Additionally, September’s humidity is higher at 79%, while August enjoys a milder 73%. For more detailed comparisons, you can check Sark weather in August.

In comparing the weather of September and October, one can observe a noticeable shift towards cooler and wetter conditions. September typically experiences a mild range of temperatures, with an average of 17°C (62°F) and a maximum of 22°C (72°F). In contrast, October brings a drop in both average and maximum temperatures, settling at 15°C (59°F) and 20°C (68°F), respectively. Additionally, October is marked by significant increases in rainfall, with precipitation reaching 152 mm (6.0 in) over 18 days, compared to September's 71 mm (2.8 in) over just 10 days. The humidity also rises from 79% in September to a more humid 89% in October, indicating a shift towards a wetter climate. For more detailed insights into October weather specifically, visit Sark weather in October.

September typically brings milder temperatures with an average of 17°C (62°F), peaking at 22°C (72°F). The month experiences lower precipitation levels, averaging 71 mm (2.8 in) over about 10 wet days, accompanied by a humidity level of 79%. In contrast, November sees a notable drop in temperatures, with an average of 12°C (54°F) and a maximum of 17°C (62°F). This month is considerably wetter, receiving 129 mm (5.1 in) of rain across approximately 19 days, and the humidity rises to 92%. For a closer look at conditions, check out Sark weather in November.

In September, temperatures are generally milder, with averages around 17°C (62°F) and highs reaching 22°C (72°F), while the month experiences approximately 71 mm (2.8 in) of precipitation over about 10 days. In contrast, December brings noticeably cooler weather, with average temperatures dropping to 10°C (51°F) and maximums only hitting 14°C (57°F), alongside significantly higher rainfall totaling 177 mm (7.0 in) over 21 days. Additionally, December’s humidity levels rise to 92%, compared to September's 79%, making the latter month feel less damp overall. For more details on December's climate, visit Sark weather in December.

Compare Sark's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Sark

As September rolls in, Sark experiences a gentle transition into autumn, marked by a delightful mix of mild temperatures and noticeable precipitation. With an average temperature hovering around 17°C, it's noticeably cooler than the balmy summer months, yet still inviting for outdoor activities. The humidity levels remain high at 79%, adding a touch of warmth to the crisp air. Rainfall becomes more frequent, with ten days seeing a total of 71 mm, signaling the shift from the dry, sunny days of summer to the wetter, more unpredictable weather of fall. For a deeper dive into Sark's climate nuances, explore more at Sark Climate.