September Weather in Cobh, Ireland

Last updated: March 17, 2025

September in Cobh, Ireland brings a delightful blend of mild temperatures and a touch of moisture, perfect for autumn enthusiasts. With maximums reaching 21°C (70°F), the average temperature settles at a comfortable 15°C (58°F), while cooler nights can dip to 8°C (47°F). Visitors can expect about 67 mm (2.6 in) of rain over 11 days, contributing to the region's lush landscapes. Coupled with a humidity level of 85%, September offers a refreshing and invigorating atmosphere, inviting exploration of the scenic coastal town and its surroundings.

September Temperature in Cobh

As summer wanes and autumn approaches, September in Cobh, Ireland, offers a delightful transition with temperatures ranging from 8°C (47°F) to a pleasant 21°C (70°F). This month marks a shift from the balmy days of summer, with an average temperature of 15°C (58°F) providing a comfortable backdrop for exploring the charming coastal town. While the milder evenings reflect the lingering warmth of summer, the increasing chill in the air hints at the cooler months ahead. With the recent summer highs at around 22°C (72°F), September serves as an ideal time for visitors to enjoy outdoor sights before the temperatures start to dip significantly in October. Overall, this blend of warmth and coolness encapsulates the enchanting beauty of Cobh during early autumn.

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

The chart illustrates September temperature patterns in Cobh, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec464646495357616158545047
Data source: Temperature data for Cobh 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 Cobh

In September, Cobh, Ireland, experiences an interesting blend of moisture and mildness, with an average precipitation of 67 mm (2.6 in), distributed over 11 days. This slight decline from the summer's wetter months, such as August's 78 mm, signals a transition into the autumn season. While September remains relatively wet, it tends to be less intense than earlier months, hinting at the onset of the drier autumn period ahead. The steady rainfall pattern mirrors the overall trend seen throughout the year, where precipitation tends to peak in the latter months, particularly October and December, making Cobh a place where preparing for rain is a year-round necessity.

September Precipitation Trends in Cobh

The chart displays monthly precipitation patterns in Cobh, 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.
JanFebMarAprMayJunJulAugSepOctNovDec57100806565525678679588106
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Cobh

As summer gently transitions into autumn, September in Cobh, Ireland, sees a notable humidity level of 85%, maintaining the coastal town's characteristic moist atmosphere. This marks a slight rise from the 84% recorded in August, continuing a trend of consistently high humidity throughout the warmer months, which peaks at 85% in both June and July. Interestingly, while the humidity remains relatively stable across the year—hovering between 83% and 86%—September's values suggest a subtle increase as the days grow shorter. This added humidity contributes to the lush, green landscapes that Ireland is famed for, creating a captivating backdrop as the season shifts.

September Average Humidity in Cobh

This chart illustrates the average monthly humidity levels in Cobh, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec83%85%84%84%84%85%85%84%85%86%84%83%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Cobh

As summer gives way to autumn in Cobh, Ireland, the UV Index experiences a notable decline in September, sitting at a moderate 5. This reflects a subtle shift from the very high levels seen in the peak summer months of June and July, where sun exposure required only 15 minutes to risk burning. By September, the burn time increases back to 30 minutes, allowing residents and visitors a bit more leeway. This seasonal transition serves as a reminder to enjoy the outdoor beauty of Cobh while still taking care to protect your skin. As always, for the most accurate and up-to-date information, check the Cobh UV Index.

Maximum UV Index Levels in Cobh for September

The chart shows the monthly maximum UV Index (UVI) for Cobh 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.
JanFebMarAprMayJunJulAugSepOctNovDec124678875421
Data source: Cobh 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 Cobh

In Cobh, Ireland, September marks a beautiful transition from the sun-drenched days of summer to the cooler embrace of autumn. With an impressive 305 hours of sunshine, this month stands out as a vibrant capstone to the sunniest season. Following the peak of 407 hours in July, September maintains a robust sunlight presence, significantly surpassing the dreary winter months, which can average just over 120 hours. As the warmth gradually recedes, the shimmering light still lingers, inviting locals and visitors alike to enjoy the breathtaking coastal views and lush landscapes, making September not just a month of changing leaves but a lingering celebration of summer's glow.

Monthly Sunshine Duration in Cobh: September Highlighted

The September sunshine duration represents the total number of hours Cobh 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.
JanFebMarAprMayJunJulAugSepOctNovDec92h144h204h324h400h393h407h364h305h240h141h104h
Data source: Cobh September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Cobh During September

In Cobh, Ireland, the likelihood of sunny weather in September stands at 23%, making it one of the less promising months for sunshine. This trend aligns with a gradual decline in sunny days from the spring peak of 48% in April to the 30% seen in August. As autumn approaches, the chance of basking in the sun dips further, reflecting a general pattern that the summer months, while often variable, offer a higher probability of clear skies. Thus, if you're planning a visit to Cobh in September, it's wise to prepare for a mix of typical Irish weather, with the sun playing hard to get.

Percentage of Sunny Days in September in Cobh

The chart illustrates the percentage of sunny days in Cobh 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 Cobh experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec34%24%25%48%33%28%31%30%23%23%33%22%
Data source: Cobh September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Cobh in September

As summer fades into autumn, September in Cobh, Ireland offers a gentle transition in daylight duration. With about 12 hours of daylight, the days are still noticeably long, though shorter than the peak summer months of June and July, which bask in an impressive 16 hours of sunlight. This gradual shift hints at the approach of autumn, as daylight decreases to 10 hours in October and 8 hours by November. Notably, September retains a more generous light than the earlier winter months, making it a perfect time for outdoor explorations before darker days settle in. With each week, visitors and residents alike can savor the lingering warmth of summer while anticipating the cozy embrace of fall.

Average Daylight Hours in Cobh for September

The chart illustrates the variation in daylight duration in Cobh throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 21m9h 57m11h 55m13h 55m15h 40m16h 35m16h 6m14h 31m12h 35m10h 35m8h 48m7h 51m
Data source: Cobh daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Cobh

As September rolls into Cobh, Ireland, the winds begin to gently calm, with an average speed of 4.5 m/s (10 mph)—a subtle drop compared to the lively gusts of summer. This month marks the transition from the brisk breezes of August, which averaged 4.8 m/s (11 mph), and serves as a precursor to the more robust October winds expected to pick up to 6.0 m/s (13 mph). Interestingly, September’s winds are among the gentlest of the year, hinting at the approaching autumn while maintaining a mild, inviting atmosphere perfect for enjoying the stunning coastal views. As we move deeper into the fall, the winds will regain their strength, but for now, September offers a serene, calm reprieve.

Average September Wind Speed in Cobh

The chart displays monthly wind speed patterns in Cobh, 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.
JanFebMarAprMayJunJulAugSepOctNovDec5.98.05.84.75.44.64.04.84.5 m/s6.05.46.7
Data source: Cobh September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Cobh Compares to Other Months

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

September and January exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 8°C (47°F) to a maximum of 21°C (70°F), with an average of 15°C (58°F). The month sees around 67 mm (2.6 in) of precipitation over 11 days, coupled with a high humidity level of 85%. In contrast, January is much colder, with temperatures peaking at a maximum of 13°C (56°F) and dropping to a minimum of 1°C (33°F), averaging at 8°C (46°F). Precipitation is slightly lower at 57 mm (2.2 in) spread over 10 days, and humidity remains relatively high at 83%. For more detailed information, you can check Cobh weather in January.

In September, the weather tends to be milder with temperatures ranging from a minimum of 8°C (47°F) to a maximum of 21°C (70°F), resulting in an average of 15°C (58°F). The month sees about 67 mm (2.6 in) of precipitation over approximately 11 days. In contrast, February experiences cooler temperatures, with a minimum of 1°C (33°F) and a maximum of 13°C (56°F), averaging only 8°C (46°F). February is also wetter, receiving 100 mm (3.9 in) of rainfall spread across about 15 days, yet both months share the same humidity level of 85%. For more detailed information, check out Cobh weather in February.

September and March present notably different weather profiles. In September, temperatures range from a minimum of 8°C (47°F) to a maximum of 21°C (70°F), with an average of 15°C (58°F), making it a mild month. The precipitation is relatively moderate at 67 mm (2.6 in) across 11 days, while humidity levels hover around 85%. Conversely, March is much cooler, with temperatures dipping as low as -2°C (28°F) and averaging 8°C (46°F), peaking at 13°C (56°F). The month sees slightly higher precipitation at 80 mm (3.2 in) over 14 days and a similar humidity level of 84%. For a detailed look at the weather in March, you can visit Cobh weather in March.

In comparing the weather between September and April, September generally offers milder temperatures, with averages around 15°C (58°F) compared to April's cooler average of 9°C (49°F). While both months experience similar levels of precipitation—67 mm in September and 65 mm in April—September tends to have slightly more rainy days, averaging 11 compared to April's 10. Humidity levels are fairly similar, with September at 85% and April at 84%. Overall, September provides a warmer and slightly wetter climate, making it a more pleasant month for outdoor activities. For a detailed look at April's weather, you can check Cobh weather in April.

In comparing the weather of September and May, September tends to be slightly warmer, with average temperatures ranging from a minimum of 8°C (47°F) to a maximum of 21°C (70°F), compared to May's range of 5°C (41°F) to 19°C (66°F). Both months experience similar levels of precipitation, with September recording 67 mm (2.6 in) and May closely following at 65 mm (2.5 in), and each witnessing about 11 days of rain. Humidity in September is marginally higher at 85%, while May maintains a comfortable level of 84%. For more specific information on May weather, check out Cobh weather in May.

In comparing the weather of September and June, we find that both months share a similar range of maximum temperatures, with highs reaching up to 21°C (70°F). However, September is slightly warmer overall, with an average temperature of 15°C (58°F) compared to June's 14°C (58°F). Both months experience high humidity levels of 85%, but September tends to have more rainfall, with 67 mm (2.6 in) across 11 days, while June sees a lower total of 52 mm (2.0 in) over 9 days. For more detailed weather information about June, you can check Cobh weather in June.

In comparing the weather between July and September, we see some notable differences. July tends to be slightly warmer, with minimum temperatures around 11°C (51°F) and average highs reaching 22°C (73°F). In contrast, September's temperatures drop, featuring minimums of 8°C (47°F) and average highs of 21°C (70°F). Precipitation is also slightly higher in September at 67 mm (2.6 in) over 11 days, compared to July's 56 mm (2.2 in) over the same number of days. Both months have similar humidity levels at 85%, but September's cooler temperatures signal the approach of autumn. For more details, you can check Cobh weather in July.

In comparing the weather between August and September, it is evident that September brings slightly cooler temperatures, with average highs of 21°C (70°F) compared to August's 22°C (71°F). The minimum temperatures in September dip to 8°C (47°F), while in August they remain higher at 10°C (51°F). Additionally, both months experience notable precipitation, with September totaling 67 mm (2.6 in) over 11 days and August receiving more rainfall at 78 mm (3.1 in) across 12 days. Humidity remains similar, with September averaging at 85% and August at 84%. For a detailed look at August weather, visit Cobh weather in August.

In comparing the weather between September and October, we see a noticeable drop in temperatures, with October's average reaching 12°C (54°F) compared to September's 15°C (58°F). The minimum temperatures in October are cooler as well, dipping to 4°C (40°F) versus September's mild 8°C (47°F). Additionally, October experiences more precipitation, totaling 95 mm (3.7 in) over 14 days, compared to September's 67 mm (2.6 in) over 11 days. Humidity remains relatively consistent, at 86% in October and 85% in September. For more detailed information, check out Cobh weather in October.

September and November exhibit notable differences in weather patterns. September enjoys slightly warmer temperatures, with averages around 15°C (58°F) and a maximum of 21°C (70°F), while November cools down significantly, averaging only 10°C (50°F) and peaking at 15°C (59°F). Additionally, precipitation increases in November to 88 mm (3.5 inches) over 14 days, compared to September's 67 mm (2.6 inches) across 11 days. Despite the slight dip in humidity, remaining high at 84% in November, both months are characterized by their dampness, making for a notably crisp and cool transition into the winter months. For more specific insights, you can check Cobh weather in November.

September and December present contrasting weather patterns that highlight the transition from late summer to early winter. In September, temperatures range from a minimum of 8°C (47°F) to a maximum of 21°C (70°F), with an average of 15°C (58°F). Precipitation is relatively moderate at 67 mm (2.6 in) over approximately 11 days, accompanied by high humidity levels at 85%. By December, the weather has significantly cooled, with temperatures dropping to a minimum of 1°C (34°F) and an average of 9°C (48°F), peaking at 14°C (57°F). This month also experiences increased precipitation, totaling 106 mm (4.2 in) across around 17 days, and slightly lower humidity at 83%. For a detailed look at December weather specifics, visit Cobh weather in December.

Compare Cobh's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Cobh

As summer fades into autumn, September in Cobh brings a gentle transition with mild temperatures averaging around 15°C (58°F). The month is characterized by an increase in humidity, making the air feel a bit heavier, while rainfall becomes more frequent, with 11 days seeing precipitation. Compared to the warmer summer months, September offers a refreshing yet unpredictable climate, perfect for those who enjoy a mix of sunny spells and occasional showers. For more detailed insights, visit Cobh Climate.