Last updated: August 21, 2025
Experience the charm of Saint Peter Port, Guernsey in September, where the weather offers a delightful blend of mild temperatures and refreshing coastal breezes. With maximum highs reaching 21°C (71°F) and an average of 17°C (62°F), the climate encourages outdoor activities amidst stunning scenery. The month sees a minimum temperature of 12°C (54°F), ensuring a cozy atmosphere as the days shorten. While 63 mm (2.5 in) of rainfall graces the island on 9 days, the landscape flourishes, enveloped in a lush, green embrace. With a humidity level of 76%, visitors can expect a pleasantly invigorating environment that complements the beauty of this captivating destination.
As September graces Saint Peter Port, Guernsey, the temperatures begin to transition from the warm embrace of summer to the cool kiss of autumn. With minimums around 12°C (54°F) and averages peaking at 17°C (62°F), the month strikes a harmonious balance, allowing residents and visitors alike to enjoy the lingering warmth. Highs reach a pleasant 21°C (71°F), making it an ideal time for outdoor activities before the chill sets in. Compared to the preceding summer months, September offers a gentle decline in temperatures, yet still maintains enough warmth to savor the scenic beauty of the island. This mild climate creates a compelling backdrop for exploring Saint Peter Port, where the inviting coastal charm perfectly complements the early autumn atmosphere.
As September unfolds in Saint Peter Port, Guernsey, the month brings a modest yet notable increase in precipitation, with an average of 63 mm (2.5 in) falling over nine days. This gradual rise in rainfall marks a transition from the drier summer months, where July and August saw significantly lower totals of 37 mm (1.5 in) and 50 mm (2.0 in) respectively. As autumn approaches, the frequency of rainy days begins to resemble the wetter months ahead, with October's average skyrocketing to 144 mm (5.7 in) and 17 rainy days. Thus, September serves as a gentle reminder of the changing seasons, bridging the gap between the residual warmth of summer and the impending chill of autumn, indicating that nature is preparing for the more dramatic shifts that the latter months will bring.
As September rolls into Saint Peter Port, Guernsey, the air begins to shift, with humidity levels settling at 76%. This marks a slight increase from the drier summer months, where July experienced the lowest humidity at 63%. Compared to August's 71%, September showcases a transition as the summer warmth recedes, giving way to the onset of autumn. Interestingly, this month serves as a precursor to the wetter conditions ahead, as humidity levels rise again toward the year's end, culminating in the winter months with high readings of 89% in October and 90% from November through December. The progression from the peak summer dryness to the more humid fall emphasizes the region's maritime climate influences, creating a unique atmospheric rhythm throughout the year.
In September, Saint Peter Port experiences a UV Index of 6, indicating a high exposure category with a burn time of 25 minutes. This marks a transition from the very high levels seen in the summer months, with the index gradually decreasing from its peak in June and July. Despite this decline, it remains essential to take precautions when spending time outdoors, particularly during midday hours. As autumn approaches, the UV Index continues to trend downward, but awareness of sun safety remains crucial. For more detailed information on UV levels throughout the year, visit Saint Peter Port UV Index.
UV Risk Categories
As summer transitions into autumn, September in Saint Peter Port, Guernsey continues to bask in a generous 338 hours of sunshine. This marks a delightful drop from the dazzling heights of July and June, which boast over 400 sunny hours, yet still comfortably outshines the gloomier winter months. With daylight gradually waning and the crispness of fall beginning to set in, September serves as a gentle reminder of summer's warmth before the landscape transforms. While the sun may begin to dip, the charm of the season lingers, encouraging outdoor adventures amidst the stunning coastal scenery.
September in Saint Peter Port, Guernsey, brings a modest 43% chance of sunny weather, a refreshing end to the summer months. As the season transitions, the likelihood of sunshine slightly dips from August’s pleasant 42%, yet it remains higher than the colder months that follow. This trend showcases a gradual decrease in sunny days from the peak in April, which boasts a robust 62% chance of sun. After the sunny days of summer, September offers a balanced mix of light and gloom, inviting visitors to savor the lingering warmth while hinting at the cooler, cloudier autumn ahead.
As summer transitions into autumn, September in Saint Peter Port, Guernsey brings a gentle decline in daylight, offering about 12 hours of sunlight each day. This marks a noticeable decrease from the peak of 16 hours in June, reflecting the gradual shift towards shorter days as the year progresses. After basking in the fullness of summer, residents and visitors alike can savor the moderate warmth and vibrant early-autumn hues before daylight dips further to 10 hours by October. The month serves as a beautiful bridge, blending the lingering brightness of summer with the cozy embrace of the coming fall, making every sunset a unique experience.
As summer transitions to autumn, September in Saint Peter Port, Guernsey brings a gentle breeze, with an average wind speed of 6.1 m/s (14 mph). This marks a noticeable decline from the bustling winds of earlier months, particularly July and August, which saw speeds around 6.0 m/s and 6.6 m/s, respectively. The shift from the lighter summer air into a brisker October, with winds picking up to 8.2 m/s (18 mph), hints at the approaching winter to come. This subtle easing in wind speed offers a peaceful atmosphere, perfect for enjoying the scenic coastal vistas, while also foreshadowing the more vigorous gusts that characterize the end of the year.
Weather in Saint Peter Port varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Saint Peter Port, focusing on differences in temperature, rainfall, humidity, and UV levels.
When comparing the weather in September and January, it's clear that the two months offer distinctly different climates. September typically enjoys mild temperatures, with a minimum of 12°C (54°F), an average of 17°C (62°F), and a maximum of 21°C (71°F). This month experiences precipitation over 9 days, averaging 63 mm (2.5 in) and maintains a comfortable humidity level of 76%. In contrast, January is significantly cooler, with temperatures ranging from a minimum of 3°C (37°F) to a maximum of 14°C (57°F), and an average temperature of 9°C (49°F). This month has higher precipitation levels at 94 mm (3.7 in) spread over 14 days, coupled with increased humidity at 89%. For a closer look at the specifics of January weather, you can check out Saint Peter Port weather in January.
In comparing the weather of September and February, it's clear that September offers milder temperatures with an average of 17°C (62°F), compared to February's chillier average of just 9°C (48°F). September typically sees minimum temperatures around 12°C (54°F), while February's lows can drop to 0°C (33°F). Additionally, February experiences more precipitation, totaling 86 mm (3.4 in) over 16 days, compared to September's 63 mm (2.5 in) over just 9 days. Humidity levels are higher in February at 88%, compared to 76% in September, contributing to a noticeably different feel in the air. For further details on February weather, you can check out Saint Peter Port weather in February.
In September, the weather tends to be milder with average temperatures ranging from a minimum of 12°C (54°F) to a maximum of 21°C (71°F), accompanied by a moderate humidity of 76%. This month experiences relatively less precipitation, totaling 63 mm (2.5 in) over about 9 days. In contrast, March is notably cooler, with average temperatures hovering between 0°C (32°F) and 13°C (55°F), while humidity rises to 85%. March also sees higher rainfall, accumulating 73 mm (2.9 in) across 15 days. For more detailed information on the March climate specifics, you can refer to Saint Peter Port weather in March.
When comparing the weather in September and April, September tends to be notably warmer and more pleasant. With average temperatures reaching around 17°C (62°F) and maximums of 21°C (71°F), September offers a comfortable climate for outdoor activities. In contrast, April presents cooler conditions, with an average temperature of just 10°C (50°F) and maximums of 15°C (59°F). Additionally, September experiences higher humidity levels at 76%, compared to April's 84%, which may make the early spring month feel a bit damp despite its lower precipitation of 34 mm (1.3 in) over 8 days. For more specific details on the weather in April, you can check Saint Peter Port weather in April.
In comparing the weather between September and May in Saint Peter Port, September tends to be warmer, with average temperatures ranging from 12°C to 21°C (54°F to 71°F), while May sees cooler temperatures, ranging from 7°C to 18°C (45°F to 65°F). September also experiences slightly more rainfall, with 63 mm (2.5 in) over 9 days, compared to May's 55 mm (2.2 in) over 8 days. Humidity levels are marginally higher in May at 81%, compared to 76% in September. For a more detailed look at May's climate, you can explore Saint Peter Port weather in May.
When comparing the weather in September to that of June, September generally presents milder temperatures with a minimum of 12°C (54°F) and an average of 17°C (62°F), compared to June's minimum of 11°C (53°F) and average of 14°C (58°F). While the maximum temperature in September reaches 21°C (71°F), June's peak is slightly lower at 19°C (67°F). Precipitation levels are fairly similar, with September receiving 63 mm (2.5 in) over 9 days, just slightly higher than June's 59 mm (2.3 in) over 8 days. Both months experience high humidity, although September is slightly less humid at 76%, compared to June's 77%. For more details on June weather, you can check Saint Peter Port weather in June.
In comparing the weather between September and July, we observe that September tends to be slightly cooler, with average temperatures around 17°C (62°F) compared to July's average of 16°C (62°F). Both months experience a maximum temperature of 21°C (71°F), but July starts warmer with a minimum temperature of 14°C (57°F) versus September's 12°C (54°F). Additionally, September sees more precipitation, totaling 63 mm (2.5 in) over 9 days, while July has just 37 mm (1.5 in) of rainfall over 7 days. The humidity is also higher in September at 76%, compared to 63% in July. For more details on July weather, you can visit Saint Peter Port weather in July.
In September, the weather shows a slight cooling trend compared to August, with minimum temperatures dropping from 14°C (57°F) to 12°C (54°F). Both months maintain a similar average temperature of around 17°C (63°F), but September's maximum temperature is slightly lower at 21°C (71°F) compared to August's 22°C (72°F). Precipitation increases in September to 63 mm (2.5 in), with rain expected on 9 days, while August sees less rain at 50 mm (2.0 in) over the same number of days. Additionally, humidity rises in September to 76%, compared to 71% in August, contributing to a more humid feel as the summer transitions into autumn. For more details on August weather specifically, you can visit Saint Peter Port weather in August.
September and October present a noticeable transition in weather conditions. In September, temperatures range from a mild 12°C (54°F) at night to a comfortable average of 17°C (62°F) during the day, with a maximum of 21°C (71°F). The month experiences 63 mm (2.5 in) of precipitation over 9 days, accompanied by a humidity level of 76%.
In contrast, October brings cooler temperatures, with a minimum of 9°C (48°F) and an average of 15°C (59°F), peaking at 20°C (68°F). Precipitation significantly increases to 144 mm (5.7 in) over 17 days, and humidity rises to 89%. This shift marks October as a wetter and cooler month compared to September. For a more detailed look at the weather specifics for this time, you can visit Saint Peter Port weather in October.
In comparing the weather between September and November, it is evident that November presents a cooler and wetter climate. September enjoys milder temperatures, with averages around 17°C (62°F) and a maximum of 21°C (71°F), while November sees a drop to an average of 12°C (54°F) and a maximum of 17°C (63°F). Precipitation also increases significantly in November, with 126 mm (5.0 in) of rain over 18 days compared to September's 63 mm (2.5 in) over 9 days. Additionally, November experiences higher humidity levels at 90%, in contrast to September's 76%. For more details on the weather conditions during this time, check out Saint Peter Port weather in November.
In September, the weather in Saint Peter Port is notably milder, with average temperatures ranging from 12°C (54°F) to a comfortable high of 21°C (71°F). The month sees moderate precipitation, totaling 63 mm (2.5 in) over approximately 9 days, and a humidity level of 76%. In contrast, December brings significantly cooler temperatures, with minimums around 5°C (41°F) and maximums reaching only 14°C (58°F). This month experiences much heavier rainfall, accumulating 163 mm (6.4 in) across 21 days, and higher humidity levels at 90%. For more details on December weather, visit Saint Peter Port weather in December.
As summer transitions to autumn, September in Saint Peter Port brings a delightful mix of mild temperatures and increased humidity. With an average temperature around 17°C (62°F), locals and visitors alike can enjoy pleasant days while experiencing a slight uptick in rainfall, averaging 63 mm over about nine days. This shift in weather sets September apart from the hotter, drier summer months, making it an ideal time for those who appreciate the richness of fall without the chill of winter. For more detailed insights into what to expect, visit Saint Peter Port Climate.