Last updated: March 17, 2025
In September, Donegal, Ireland, showcases a unique blend of mild temperatures and frequent rainfall. With a maximum of 24°C (76°F), the days can be pleasantly warm, while the average temperature settles at a cool 12°C (55°F). However, temperatures can drop to a brisk minimum of 2°C (36°F) at night. This month experiences an average rainfall of 112 mm (4.4 in) over 18 days, contributing to the region's lush landscapes. The high humidity at 87% adds a touch of freshness to the air, making September a captivating time to explore the natural beauty of Donegal, where each day offers a mix of sunshine and rain.
In September, Donegal showcases a delightful transition towards autumn, marked by mild temperatures that invite outdoor exploration. With minimums around 2°C (36°F) to maximums reaching 24°C (76°F), the average temperature hovers at a comfortable 12°C (55°F), creating a pleasant climate for visitors. This month stands out as temperatures begin to dip from the warmth of summer, yet still retain a hint of lingering heat, encouraging locals and tourists alike to bask in the picturesque landscapes. As the days grow shorter, the vibrant hues of fall start to emerge, enhancing the charm of this stunning Irish locale.
September in Donegal, Ireland, sees a notable precipitation amount of 112 mm (4.4 in), a decrease from the preceding month's significant rainfall of 164 mm (6.5 in). Rainfall occurs over approximately 18 days, indicating that while the month remains relatively wet, it is less intense than the summer peak. As the year's transition continues, September sets the stage for the wetter months ahead, with October and November expected to bring 139 mm (5.5 in) and 116 mm (4.6 in), respectively. This trend reflects a typical autumn pattern, where precipitation becomes more frequent, helping to replenish the lush green landscapes that Donegal is renowned for.
As summer transitions into autumn, September in Donegal, Ireland, experiences a subtle uptick in humidity, reaching 87%. This marks a shift from the warmer months of July and August, which also recorded high humidity levels of 86%. Following the consistent range of 83% to 86% from the late spring to summer, September's increase signals the onset of the wetter season, coinciding with the arrival of autumn rains. This trend continues into October and November, where humidity levels remain high at 87% and 88%, respectively. Overall, Donegal's climate presents a fascinating pattern, with increased humidity reflecting the region’s lush, vibrant landscapes and hinting at the cozy, often rainy months ahead.
As September unfolds in Donegal, the UV Index reflects a transition from the intense summer months to the gentler embrace of autumn. With a UV Index of 5, this month falls into the moderate exposure category, requiring approximately 30 minutes of unprotected sun exposure before skin burning may occur. Compared to the peak values of 8 seen during July and June, September offers a more manageable sun experience, yet it still calls for moderate caution. It's a reminder that as the seasons shift, so too does our relationship with the sun. For more detailed insights, visit the Donegal UV Index.
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September in Donegal, Ireland, brings a gentle transition into autumn, featuring approximately 270 hours of sunshine. This delightful month still glimmers with summer's lingering warmth, following a peak in May with 385 hours of radiant sunshine. As the year progresses, sunshine hours gradually decline from the summer's height, with July and August maintaining robust totals of 367 and 323 hours, respectively. The shift into September marks a noticeable dip, yet it remains generously sunlit compared to the dim winter months, which see a sharp contrast with November and December showing just 109 and 75 hours. Overall, September serves as a bridge of golden light, easing into the cooler, more subdued days ahead.
In Donegal, Ireland, the likelihood of sunny weather reaches its peak in the spring, with April basking in 35% sunshine, while the summer months tend to be less reliable, showcasing a drop to around 16-20%. As September rolls in, the chance of sun dips further to 15%, indicating a gradual shift towards the autumn season. This trend reveals that while summer offers some potential for sunshine, September and the subsequent months return to the cooler and typically cloudier climate synonymous with Donegal. The overall pattern highlights how sunshine becomes less frequent as the year progresses, inviting visitors to embrace the beauty of Donegal’s often moody weather rather than chase elusive sunny days.
As summer fades into autumn in Donegal, Ireland, September marks a subtle yet significant shift in daylight patterns. With an average of 12 hours of daylight, the month serves as a bridge between the long, sunlit days of June and July, which boast up to 17 hours of light, and the much shorter days of October, dipping to 10 hours. This gradual decline is part of a well-defined annual rhythm where the longer days of spring and summer give way to the cozy embrace of autumn. As the leaves begin to turn and the air grows crisper, September offers a delightful balance, allowing residents and visitors alike to savor the lingering warmth of daylight before the darker months set in.
As September unfolds in Donegal, the winds begin to settle into a gentle rhythm, with an average speed of 3.4 m/s (8 mph). Following the slightly breezy August, where winds averaged 3.1 m/s (7 mph), September offers a calm reprieve that hints at the transition into autumn. This month’s winds, while moderate, maintain a consistent theme established in the early spring months, with speeds dipping slightly from the summer's calmest July winds, which reached only 2.5 m/s (5 mph). As the month progresses and nature prepares for the cooler days ahead, October will see a rise again in wind speeds, suggesting a dynamic and ever-changing Irish landscape, where the breezes tell the stories of shifting seasons.
The weather in Donegal 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 Donegal and find detailed weather information for every month.
In September, temperatures range from a chilly 2°C (36°F) at night to a pleasant 24°C (76°F) during the day, making it a much warmer month overall with an average temperature of 12°C (55°F). The month is characterized by significant rainfall, with 112 mm (4.4 in) spread over 18 days, and a high humidity level of 87%. In contrast, January sees colder conditions, with minimum temperatures dropping to -5°C (24°F) and an average of just 5°C (42°F). Precipitation is slightly lower at 95 mm (3.7 in) over 16 days, and humidity levels are moderately lower at 84%. For those looking for specific weather details in this mid-winter month, insights can be found in this guide: Donegal weather in January.
In comparing the weather between September and February, it’s clear that September experiences milder temperatures, with a minimum of 2°C (36°F) and an average of 12°C (55°F), whereas February sees colder conditions, starting as low as -5°C (23°F) and averaging only 5°C (42°F). Rainfall is notably higher in February, with 142 mm (5.6 in) accumulating over 17 days, in contrast to September's 112 mm (4.4 in) across 18 days. Although February has a slightly lower humidity level at 84% compared to September's 87%, both months tend to be quite wet. For a more detailed look at February weather, you can visit Donegal weather in February.
September and March both present unique weather patterns. September tends to be milder, with average temperatures ranging from a low of 2°C (36°F) to a high of 24°C (76°F), while March is cooler, starting with temperatures as low as -5°C (24°F) and reaching a maximum of 17°C (62°F). Precipitation is similar in both months, with September receiving 112 mm (4.4 in) and March slightly wetter at 128 mm (5.0 in), although both experience rainfall on 18 days. Humidity is also relatively high, with September at 87% and March slightly lower at 83%. For more detailed insights on March weather, check Donegal weather in March.
In comparing the weather of September and April, it's evident that September typically enjoys warmer temperatures. Average highs in September reach 24°C (76°F), while April's peaks only reach 20°C (69°F). However, April starts off cooler with minimum temperatures dipping as low as -2°C (28°F), compared to September's milder minimum of 2°C (36°F). Precipitation is also notably lower in April, with only 65 mm (2.6 in) over 14 days, compared to September's 112 mm (4.4 in) across 18 days. Both months have high humidity levels, with September at 87% and April slightly less at 84%. For a closer look at April weather specifics, you can visit Donegal weather in April.
In comparing the weather of September and May, we see distinct differences. September boasts slightly warmer temperatures, with a minimum of 2°C (36°F) and a maximum of 24°C (76°F), leading to an average of 12°C (55°F). This month experiences higher precipitation as well, with 112 mm (4.4 in) over 18 days, and humidity levels at 87%. In contrast, May, while colder with a minimum of -1°C (30°F) and an average of 11°C (52°F), reaches a similar maximum temperature of 25°C (77°F). It has lower precipitation at 85 mm (3.4 in) over 14 days and slightly less humidity at 83%. For more detailed insights, you can check Donegal weather in May.
In comparing the weather between September and June, there are notable differences in temperature and overall conditions. September features a range of temperatures from a minimum of 2°C (36°F) to a maximum of 24°C (76°F) with an average of 12°C (55°F), while June experiences slightly warmer temperatures, ranging from a minimum of 4°C (40°F) to a maximum of 27°C (82°F) and an average of 13°C (56°F).
Precipitation levels are quite similar, with September receiving 112 mm (4.4 in) of rain over 18 days and June seeing a marginally higher amount of 114 mm (4.5 in) over 17 days. Humidity also differs slightly, with September at 87% and June at 83%. For more details on June weather specifically, you can visit Donegal weather in June.
September and July exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 2°C (36°F) to a maximum of 24°C (76°F), with an average of 12°C (55°F), leading to a cooler overall feel compared to July, which enjoys milder temperatures that span from 6°C (44°F) to 27°C (81°F) with an average of 15°C (58°F). While both months see similar levels of precipitation, with September recording 112 mm (4.4 in) over 18 days and July experiencing 108 mm (4.2 in) over 17 days, September tends to be more humid, averaging 87% compared to July's 86%. For more detailed insights, you can check out Donegal weather in July.
In comparing September and August weather, September experiences slightly cooler temperatures, with a minimum of 2°C (36°F) and an average of 12°C (55°F), while August sees a minimum of 5°C (41°F) and an average of 14°C (58°F). Despite having a similar maximum temperature of around 23-24°C (73-76°F), September is characterized by increased precipitation, totaling 112 mm (4.4 in) over 18 days, compared to August's 164 mm (6.5 in) over 22 days. Humidity levels remain high in both months, with September at 87% and August at 86%. For more details on August weather in Donegal, visit Donegal weather in August.
September and October exhibit a gradual shift in weather conditions. September tends to be milder, with average temperatures ranging from 2°C (36°F) at the low end to a comfortable 24°C (76°F) at the high end, while October sees a drop in average temperatures to 0°C (32°F) minimum and 19°C (67°F) maximum. Both months experience high humidity at 87%, but October is wetter, receiving approximately 139 mm (5.5 in) of precipitation over 20 days compared to 112 mm (4.4 in) over 18 days in September. For more detailed weather information, you can check Donegal weather in October.
September and November present contrasting weather patterns, characterized by notable shifts in temperature and precipitation. In September, the temperatures range from a minimum of 2°C (36°F) to a maximum of 24°C (76°F), with an average of 12°C (55°F), allowing for relatively mild and pleasant days. However, September experiences significant rainfall, with 112 mm (4.4 in) distributed over 18 days and humidity levels hovering around 87%.
In contrast, November brings cooler temperatures, with a minimum of -4°C (25°F) and a maximum of 15°C (58°F), resulting in an average temperature of just 7°C (45°F). Precipitation slightly increases to 116 mm (4.6 in) over 20 days, coupled with a slightly higher humidity of 88%. For a detailed look at what to expect during this month, you can check out Donegal weather in November. Overall, while September remains warmer and slightly drier, November transitions into colder temperatures and frequent rain.
September and December exhibit quite contrasting weather patterns. In September, temperatures range from a minimum of 2°C (36°F) to a maximum of 24°C (76°F), with an average of 12°C (55°F). The month experiences significant rainfall, totaling 112 mm (4.4 inches) over 18 days, coupled with high humidity levels at 87%. In contrast, December sees much cooler temperatures, with lows dipping to -2°C (28°F) and highs reaching only 13°C (55°F), averaging around 6°C (43°F). Precipitation increases slightly to 131 mm (5.2 inches) over 21 days, and humidity remains relatively high at 84%. For detailed insights into December weather, you can visit Donegal weather in December.
As September unfolds in Donegal, visitors can expect a shift toward cooler and wetter conditions compared to the preceding summer months. With temperatures averaging a brisk 12°C, this transitional period brings refreshing breezes and an increased likelihood of rain, as evidenced by the 18 days of precipitation. The high humidity of 87% adds to the crispness in the air, making it a perfect time for cozy walks along the picturesque coast or the lush countryside. For those seeking to delve deeper into the distinctive patterns of Donegal's weather throughout the year, be sure to check out Donegal Climate.