Last updated: March 17, 2025
In September, Portmarnock, Ireland, experiences a delightful transition into autumn, with maximum temperatures reaching 22°C (72°F) alongside an average of 14°C (57°F). Early autumn crispness is evident, as the minimum temperatures dip to 4°C (39°F). This month witnesses 70 mm (2.7 in) of precipitation, spread over 13 days, contributing to the region's lush landscapes. With a high humidity level of 86%, the air feels refreshingly cool, making September a captivating month for leisurely strolls along the scenic coastline and enjoying the vibrant autumnal hues.
As September arrives in Portmarnock, Ireland, the temperatures begin to shift towards the cooler side, reflecting the transition from summer to autumn. With a minimum of 4°C (39°F) and an average temperature of 14°C (57°F), the month presents a mild climate that's perfect for outdoor activities, yet a light jacket may be necessary for the chillier evenings. The maximum temperature can reach up to 22°C (72°F), offering lingering warmth reminiscent of summer's end. Comparing it to the warmer months of July and August, where highs reached 27°C (80°F) and 23°C (74°F) respectively, September serves as a gentle reminder that the summer days are numbered, while still inviting a pleasant experience for both locals and visitors alike.
September in Portmarnock, Ireland, sees 70 mm (2.7 in) of precipitation, making it a transition month as autumn sets in. This amount is consistent with a typical Irish September, featuring around 13 days of rainfall that keeps the landscape lush and vibrant. Following the wetter summer months, such as August's 95 mm (3.7 in), September's rainfall starts to moderate, indicating a gradual shift towards cooler, drier conditions in the months ahead. Overall, this month acts as a bridge between the plentiful summer showers and the increasingly erratic precipitation patterns of the autumn, setting the stage for the heavier rains to come in October and November.
September in Portmarnock, Ireland, sees a notable consistency in humidity, with levels reaching 86%, matching the peak observed in both July and February. As summer transitions into autumn, the air remains richly saturated, hinting at the lingering warmth of the season. Throughout the year, humidity remains relatively high, typically hovering between 83% and 87%, with October marking a slight increase to 87%, just after September's elevated readings. This persistent humidity not only characterizes Portmarnock's coastal climate but also sets the stage for the cooler, moisture-laden months ahead, making it a unique blend of maritime and seasonal influences.
In September, Portmarnock experiences a moderate UV Index of 5, indicating that while sun exposure is generally safe, caution is still advised for extended periods outdoors. This month's index reflects a slight decrease from the high levels seen in the summer, where June and July reached a peak UV Index of 8. As autumn approaches, the burn time increases to 30 minutes, allowing for longer outdoor activities without the immediate concern of sunburn. It's crucial to remain mindful of sun safety as the transition from the intense summer sun yields to more moderate conditions. For a comprehensive look at the UV levels throughout the year, check out the details at Portmarnock UV Index.
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As summer yields to autumn, September in Portmarnock, Ireland embraces a gentle transition with 288 hours of sunshine, marking a delightful decline from the sun-drenched peak of August. The steady decrease in daylight hours reminds us of the vibrant summer gone by, with May basking in the brightest glow at 385 hours. While sunlight wanes toward the end of the year, both October and November follow September's lead, offering a blend of crisp air and softer light. With each passing month, the rhythm of the seasons unfolds, painting a picturesque backdrop to this coastal haven, inviting us to savor the lingering warmth and beauty before the darker days of winter approach.
In Portmarnock, Ireland, the likelihood of sunny weather in September stands at a modest 21%, which aligns closely with the cooler months that precede it. As summer fades, sunshine seems to become more elusive, with September showing a slight decline from the more vibrant April, which boasts a 44% likelihood. This downward trend continues through the late summer months, where the chances of sun dip to around 23% in both August and October. Notably, April emerges as the standout month for sunlight, while the transition into autumn brings a return to the lower percentages typical of winter. In essence, while September holds some charm, those yearning for sunny skies may find it less rewarding compared to the brighter days of earlier in the year.
As summer fades into autumn in Portmarnock, Ireland, September offers a gentle transition with approximately 12 hours of daylight. This marks a noticeable shift from the 16 hours enjoyed in June and July, as the days gradually shorten. Following the vibrant glow of August's 14 hours, September's daylight begins to dwindle, foreshadowing the shorter days ahead. This pattern reveals a rhythmic ebb and flow, where longer daylight hours in spring and summer give way to the cozy, intimate evenings of fall, creating a beautiful tapestry of light and shadow throughout the year.
As September arrives in Portmarnock, the winds begin to shift, with an average speed of 3.5 m/s (8 mph). This mild breeze reflects a notable decline from the gusty months of winter and the often unpredictable spring, where winds were typically stronger. In fact, the summer months see the gentlest breezes of the year, peaking in July with just 2.8 m/s (6 mph). As fall approaches, September's winds hint at the transition ahead, preparing for the more robust gusts of October and November, which return to an average of around 4.8 m/s (11 mph). This cyclical dance of wind speeds not only marks the changing seasons but also embodies the tranquil yet dynamic character of Portmarnock's coastal landscape.
The weather in Portmarnock changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Portmarnock and find detailed weather information for every month.
In September, temperatures begin to cool down as summer fades, with a minimum of 4°C (39°F) and an average of 14°C (57°F), reaching a maximum of 22°C (72°F). The month experiences more rainfall, with 70 mm (2.7 in) of precipitation over 13 days, contributing to higher humidity levels at 86%. In contrast, January presents a much colder climate, with temperatures dipping to a minimum of -3°C (27°F) and an average of 6°C (43°F), peaking at 14°C (58°F). Rainfall decreases slightly to 53 mm (2.1 in) over 10 days, while humidity remains relatively stable at 85%. This stark difference highlights the transition from early autumn to the depths of winter. For more detailed insights, check out Portmarnock weather in January.
When comparing the weather in September and February, we see a notable difference in temperatures and conditions. September boasts a milder climate with temperatures ranging from a minimum of 4°C (39°F) to a maximum of 22°C (72°F), averaging around 14°C (57°F). In contrast, February experiences colder conditions, with minimum temperatures dropping to -2°C (29°F) and a maximum of 15°C (58°F), averaging only 7°C (44°F). Both months feature similar humidity levels at 86%, but February receives slightly more precipitation, averaging 73 mm (2.9 in) over 14 days compared to September's 70 mm (2.7 in) across 13 days. To explore the specifics of February weather, you can visit Portmarnock weather in February.
In comparing the weather between September and March, we notice some notable differences. September has milder temperatures, with a minimum of 4°C (39°F) and an average of 14°C (57°F), while March experiences colder conditions, reaching a minimum of -3°C (26°F) and an average of 7°C (45°F). Despite having similar humidity levels at 86%, March has slightly more precipitation, with 73 mm (2.9 in) over 14 days compared to September's 70 mm (2.7 in) over 13 days. For more detailed insights, you can check out Portmarnock weather in March.
When comparing the weather in September and April, one can see distinct differences in temperature and precipitation patterns. September enjoys a more moderate climate, with average temperatures ranging from a minimum of 4°C (39°F) to a maximum of 22°C (72°F) and an average humidity of 86%. In contrast, April is cooler, featuring average temperatures that range from a minimum of -1°C (31°F) to a maximum of 19°C (67°F), with slightly lower humidity at 85%. Additionally, April experiences less precipitation, totaling 44 mm (1.7 in) over approximately 11 days, compared to September's 70 mm (2.7 in) over 13 days. For more details on April weather, you can explore Portmarnock weather in April.
September and May showcase a transition between seasons, with both months experiencing similar maximum temperatures of 22°C (72°F). However, September tends to have a slightly warmer average temperature of 14°C (57°F) compared to May's average of 12°C (53°F). Notably, September is marked by higher humidity at 86% and a slightly greater amount of rainfall, with 70 mm (2.7 in) over 13 days, while May sees 62 mm (2.4 in) of precipitation across 12 days. For more detailed information about the weather patterns in May, you can check out Portmarnock weather in May.
When comparing the weather in September and June, we see some notable differences despite their similar precipitation levels. In September, temperatures range from a chilly minimum of 4°C (39°F) to a pleasant maximum of 22°C (72°F), with an average of 14°C (57°F). In contrast, June enjoys slightly warmer weather, with minimums around 7°C (44°F) and maximums reaching 25°C (77°F), averaging 15°C (58°F). Both months experience similar precipitation, with around 70 mm (2.7 in) falling over 13 days; however, September's higher humidity at 86% can make the air feel more uncomfortable compared to June's 85%. For more specific weather information, you can visit Portmarnock weather in June.
In comparing the weather of September and July, we see distinct differences in temperature and precipitation patterns. September typically experiences lower temperatures, with a minimum of 4°C (39°F) and a maximum of 22°C (72°F), averaging at 14°C (57°F). In contrast, July is warmer, with temperatures ranging from a minimum of 8°C (47°F) to a high of 27°C (80°F), averaging 16°C (62°F). Both months have similar levels of precipitation, with September receiving about 70 mm (2.7 in) over 13 days and July slightly higher at 73 mm (2.9 in) over 12 days. Notably, humidity remains consistent in both months at 86%. For more detailed information, you can visit Portmarnock weather in July.
In comparing the weather conditions of September and August, September tends to be cooler, with average temperatures ranging from a minimum of 4°C (39°F) to a maximum of 22°C (72°F), compared to August’s warmer range of 8°C (47°F) to 23°C (74°F). Additionally, September experiences increased precipitation, with 70 mm (2.7 in) falling over 13 days, while August sees slightly higher rainfall of 95 mm (3.7 in) over 16 days. Humidity remains relatively similar, hovering at 86% in September and 85% in August. For a more detailed look at August’s weather patterns, you can check Portmarnock weather in August.
In comparing the weather between September and October, September typically experiences slightly warmer temperatures, with a minimum of 4°C (39°F) and a maximum of 22°C (72°F). The average temperature is around 14°C (57°F), while October sees a drop in temperatures, with a minimum of 2°C (36°F), an average of 11°C (53°F), and a maximum of 19°C (67°F). Precipitation levels rise slightly in October to 79 mm (3.1 in) compared to September's 70 mm (2.7 in), with both months experiencing precipitation on about 13 days. Humidity remains consistently high, increasing from 86% in September to 87% in October. For a closer look at October's weather patterns, you can check out Portmarnock weather in October.
In September, the weather is relatively mild, with temperatures ranging from a minimum of 4°C (39°F) to a maximum of 22°C (72°F), averaging 14°C (57°F). The month sees about 70 mm (2.7 in) of precipitation over 13 days, accompanied by a high humidity level of 86%. In contrast, November brings cooler temperatures, with a minimum of -1°C (31°F) and a maximum of 15°C (60°F), averaging only 8°C (48°F). Precipitation increases to 93 mm (3.6 in) over 14 days, while humidity remains constant at 86%. For more details on November weather, visit Portmarnock weather in November.
Comparing the weather between September and December reveals distinct seasonal shifts. In September, temperatures range from a mild minimum of 4°C (39°F) to a pleasant average of 14°C (57°F), peaking at a comfortable 22°C (72°F). Conversely, December experiences much cooler conditions, with minimum temperatures dropping to -2°C (30°F) and an average of 7°C (45°F), reaching a maximum of only 13°C (56°F).
Additionally, September sees about 70 mm (2.7 in) of rainfall over 13 days, while December has a slightly higher precipitation total of 85 mm (3.4 in) over 14 days. Both months exhibit similar humidity levels, with September at 86% and December slightly lower at 84%. For an in-depth look at December's weather, visit Portmarnock weather in December.
As September unfolds in Portmarnock, the weather begins to shift, bringing a youthful vibrancy that contrasts with the more temperate months of summer. The days remain pleasantly mild, with warm spells occasionally peeking through, yet the cool nights signal the approaching autumn. Precipitation becomes a more frequent companion, gracing the area nearly half the month, which heightens the lushness of the landscape. With humidity levels elevated, the air feels rich and inviting, setting the scene for the transition to the crisper days ahead. This unique blend of warmth and moisture makes September a distinct experience in the yearly climate cycle. For more information on what to expect throughout the year, explore the detailed insights at Portmarnock Climate.