Last updated: March 17, 2025
In September, Cardiff, United Kingdom experiences a varied climate characterized by a maximum temperature of 27°C (81°F) and an average of 15°C (59°F). As autumn approaches, the temperatures can dip to a minimum of 4°C (40°F). This month also sees a notable precipitation amount of 81 mm (3.2 in) over approximately 12 days, contributing to a relatively high humidity level of 79%. Whether it's the warmth of early fall or the occasional rain, September in Cardiff offers a dynamic weather experience.
In Cardiff, United Kingdom, September marks a delightful transition into autumn, where temperatures start to cool from the summer peak. The month greets visitors with a minimum temperature of around 4°C (40°F), rising to an average of 15°C (59°F) and occasionally reaching a comfortable 27°C (81°F). This gradual drop from the higher summer averages, peaking at 29°C (84°F) in August, creates a refreshing atmosphere perfect for outdoor activities. With the evenings becoming brisker, the city's charm truly shines as the vibrant hues of early autumn begin to dot the landscape. Overall, September in Cardiff offers a pleasant mix of warm days and cooler nights, making it an ideal time to explore all the cultural treasures the city has to offer.
September in Cardiff typically ushers in the early whispers of autumn, bringing with it an average precipitation of 81 mm (3.2 in) over approximately 12 days. This amount is a slight dip from the wetter summer months, yet it still contributes to the region's lush landscape. With rainfall gradually decreasing from the 97 mm experienced in August, September stands as a transitional month where the occasional shower maintains the city's green charm. As the days shorten and cooler temperatures set in, residents and visitors alike can enjoy the beauty of Cardiff's early fall, even as the promise of October's higher rainfall looms on the horizon.
As summer fades into autumn, September in Cardiff presents a notable shift in humidity levels, averaging 79%, a modest decrease from the more humid months of July and August. This transition reflects a broader trend where humidity tends to recede from the late summer highs, such as July's 70% and August's 73%. However, September's figure is still relatively high compared to the months ahead, indicating that the city remains enveloped in moisture as it prepares for the wetter autumn months. Overall, Cardiff's fall season starts with an atmosphere that retains some of summer's humidity while hinting at the impending increase, with October spiking back up to 89%, showcasing the city’s characteristic dampness.
As summer transitions into autumn in Cardiff, the September UV Index reveals a moderate to high exposure category with a value of 6. This indicates that while the sun's intensity begins to wane compared to the peak summer months, protective measures are still essential, as the burn time remains significant at 25 minutes. This gradual decline from the intense levels of July and June, which both peaked at 8, highlights the shifting patterns of sun exposure. As outdoor activities continue to thrive, it's crucial to stay informed about UV levels—check out the details at Cardiff UV Index to help you plan safely for sunny days ahead!
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As summer gracefully transitions into autumn, September in Cardiff showcases a remarkable 279 hours of sunshine, marking a delightful balance between the lingering warmth of summer and the upcoming chill of fall. This month is notably less sun-drenched than July and August, which boast impressive totals of 399 and 345 hours respectively, but it still offers a generous glow compared to the dimmer winter months. The gradual decline in sunshine hours hints at the seasonal shift, with October's 224 hours looming ahead. Yet, September remains a golden opportunity to enjoy the last remnants of outdoor activities, enveloped in the warmth of early autumn hues.
As September rolls in, Cardiff experiences a subtle transition from the sunny warmth of summer to the cool embrace of autumn. With a 28% chance of sunshine, this month offers more promising weather compared to the colder months like January and October, but it doesn't quite match the brightness of springtime April with its 52% likelihood. Interestingly, September's sun chances reflect a slight dip from the peak summer months, demonstrating a gradual shift in the weather patterns as daylight wanes. Despite this, outdoor enthusiasts can still catch glimpses of warmth, making the most of crisp, sun-bathed days that herald the arrival of fall.
As summer fades in September, Cardiff experiences a gentle decline in daylight, with approximately 12 hours of sunlight available each day. This marks a transition from the peak of summer, where June and July boast an impressive 16 hours of daylight, to the shorter days of autumn and winter. The gradual shift in daylight, from 15 hours in May and 14 hours in August, points towards the impending cooler months. As we head into autumn, daylight continues to diminish, ultimately leading to the darker days of October, where only 10 hours are expected, before settling into the winter pattern of 8 hours by November. This rhythmic dance of daylight encapsulates Cardiff's seasonal change, ushering in cozy evenings as the year approaches its end.
As summer transitions to autumn, September in Cardiff brings a gentle average wind speed of 3.7 m/s (8 mph), contributing to the city’s mild climate. This marks a slight increase from the calmer breezes of July and June, both averaging around 3.4 m/s and 3.5 m/s, respectively. However, compared to the earlier months of the year, September’s winds are notably softer than the gusts seen in January, February, and March, which hover around 5 m/s and above. As the days shorten and temperatures begin to dip, this subtle shift in wind patterns heralds the arrival of autumn, inviting a refreshing change to the vibrant landscape of Cardiff.
The weather in Cardiff 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 Cardiff and find detailed weather information for every month.
In September, the weather presents a warm transition into autumn, with temperatures ranging from a minimum of 4°C (40°F) to a maximum of 27°C (81°F) and an average of 15°C (59°F). This month experiences about 81 mm (3.2 in) of rainfall over 12 days, accompanied by a relatively comfortable humidity level of 79%. In contrast, January brings a notable chill, with temperatures dropping to a minimum of -3°C (27°F) and only peaking at 13°C (56°F), resulting in an average temperature of 6°C (42°F). The precipitation remains similar, at 75 mm (3.0 in) across 12 days, but the humidity increases to 88%, making January feel much colder. For more detailed insights, you can check Cardiff weather in January.
September and February present stark contrasts in weather. September boasts warmer temperatures with averages around 15°C (59°F) and highs reaching up to 27°C (81°F), while February, with an average of just 6°C (44°F) and a maximum of 15°C (60°F), feels significantly cooler. Precipitation is also notable; September receives about 81 mm (3.2 in) over 12 days, whereas February experiences slightly more with 101 mm (4.0 in) spread across 14 days. Additionally, humidity levels peak in February at 88%, compared to September's 79%, adding to the chill of the winter month. For more specific details, you can check Cardiff weather in February.
When comparing the weather in September to that in March, notable differences emerge. September typically enjoys milder temperatures, with a minimum of 4°C (40°F) and an average of 15°C (59°F), while March starts off much colder, with a low of -5°C (22°F) and an average of only 7°C (45°F). The maximum temperatures in September can reach up to 27°C (81°F), making it feel much warmer compared to March's peak of 18°C (65°F). Additionally, September experiences an average precipitation of 81 mm (3.2 in) over 12 days, while March sees slightly more rain at 97 mm (3.8 in) over 15 days. Humidity levels also tend to be higher in March, at 86%, compared to 79% in September, contributing to a different feel in the air. For more detailed insights on weather conditions, you can check Cardiff weather in March.
September and April exhibit distinct weather patterns, reflecting the transition from summer to autumn and from winter to spring, respectively. September tends to be warmer, with average temperatures ranging from a minimum of 4°C (40°F) to a maximum of 27°C (81°F), while April sees cooler temperatures, from -1°C (30°F) to 20°C (69°F) on average. Precipitation is more abundant in September, totaling 81 mm (3.2 in) over 12 days, compared to April's 57 mm (2.2 in) across 10 days. Additionally, September's humidity is slightly lower at 79% compared to April's 84%, indicating a brisker feel in the early spring month. For more information about April’s weather, check out Cardiff weather in April.
In comparing the weather between September and May, we see some intriguing similarities and differences. September generally has slightly warmer temperatures, with a minimum of 4°C (40°F) and an average of 15°C (59°F), compared to May's minimum of 2°C (35°F) and an average of 12°C (54°F). Both months experience similar levels of precipitation, with September receiving 81 mm (3.2 in) and May seeing just 79 mm (3.1 in), and both having precipitation on approximately 12 days. Humidity levels are also comparable, with September at 79% and May at 80%. For more detailed information on how the weather unfolds in May, you can check this link: Cardiff weather in May.
When comparing the weather in September and June, both months exhibit similar average temperatures, hovering around 15°C (59°F) to 15°C (60°F) with max temperatures reaching 27°C (81°F) in September and 27°C (82°F) in June. However, September tends to start cooler with a minimum temperature of 4°C (40°F) compared to June’s minimum of 7°C (45°F). Precipitation levels are quite close, with September receiving 81 mm (3.2 in) and June slightly higher at 84 mm (3.3 in), both spread over 12 days. Humidity remains fairly consistent between the two months, with September at 79% and June at 80%. For more insights, check out Cardiff weather in June.
In comparing the weather between September and July, we observe that September typically has a wider temperature range, with minimums dropping to 4°C (40°F) and maximums reaching 27°C (81°F), while July maintains a milder range with minimums around 9°C (48°F) and maximums of 28°C (82°F). Both months experience similar humidity levels, with September at 79% and July slightly lower at 70%. Interestingly, both months also see approximately 85 mm (3.3 in) of precipitation over 12 days, indicating a consistent amount of rainfall. For a more detailed view of July's climate, you can check out Cardiff weather in July.
In comparing the weather between August and September, September brings a noticeable drop in temperatures, with a minimum of 4°C compared to August's 9°C. The average temperature in September is 15°C, slightly cooler than August's 17°C, and while both months experience mild highs, September peaks at 27°C, just below August's 29°C. Precipitation is also significant in both months, with September receiving 81 mm over 12 days, which is a bit lower than August's 97 mm over 13 days. Additionally, September's humidity level is slightly higher at 79%, compared to August's 73%. For a more detailed look at August's weather, see Cardiff weather in August.
September generally offers milder temperatures, with minimums around 4°C (40°F) and maximums reaching up to 27°C (81°F), making it a transitional month with an average temperature of 15°C (59°F). However, it also experiences about 81 mm (3.2 in) of precipitation over around 12 days, leading to a relatively humid environment at 79%. In contrast, October sees a drop in average temperatures to 12°C (54°F), with minimums falling to 1°C (33°F) and maximums capping at 21°C (70°F). This month is wetter, with precipitation increasing to 135 mm (5.3 in) over approximately 16 days and humidity rising to 89%. For more detailed information, check out Cardiff weather in October.
September generally offers milder weather compared to November, with average temperatures ranging from a minimum of 4°C (40°F) to a maximum of 27°C (81°F). This month sees an average temperature of 15°C (59°F) and experiences 81 mm (3.2 in) of precipitation over about 12 days, with humidity at a comfortable 79%. In contrast, November brings a noticeable drop in temperatures, with nightly lows reaching -1°C (30°F) and daytime highs averaging only 16°C (61°F), resulting in an overall average of 9°C (48°F). Additionally, November experiences increased precipitation at 99 mm (3.9 in) across around 15 days, along with higher humidity levels at 90%. For more specific details on November's weather, you can check Cardiff weather in November.
September and December present quite contrasting weather conditions. In September, temperatures range from a minimum of 4°C (40°F) to a maximum of 27°C (81°F), with an average of 15°C (59°F). This month experiences moderate precipitation, averaging 81 mm (3.2 in) over about 12 days, coupled with a humidity level of 79%. In stark contrast, December sees much colder conditions, with temperatures dropping to a minimum of -4°C (26°F) and only reaching a maximum of 13°C (56°F), averaging around 7°C (45°F). The month is also wetter, with 130 mm (5.1 in) of precipitation over 17 days and a higher humidity of 89%. For more details on December weather, you can read more about Cardiff weather in December.
As September unfolds in Cardiff, the weather begins to transition from the warmth of summer to the crispness of autumn. While the temperatures can still hit a pleasant peak, averaging a comfortable 15°C, the significant drop to cooler lows reminds us that winter is on the horizon. With around 81 mm of rainfall spread across approximately 12 days, September is notably wetter than the preceding months, creating a lush, vibrant atmosphere. The increased humidity levels of 79% add a refreshing crispness to the air, making it a perfect time to explore the city's beautiful parks and gardens. To delve deeper into understanding the unique weather patterns throughout the year, check out our detailed guide on Cardiff Climate.