Last updated: March 17, 2025
September in London, United Kingdom, sees a delightful transition as summer gives way to autumn, with temperatures ranging from a chilly minimum of 4°C (39°F) to a comfortable maximum of 28°C (83°F). The average temperature settles around 15°C (59°F), providing an inviting climate for outdoor exploration. Visitors may encounter occasional rain, with precipitation totaling 45 mm (1.8 in) over approximately 10 days of the month. High humidity levels at 82% contribute to the lush greenery characteristic of the city, making September a beautiful time to experience London's vibrant atmosphere and scenic parks.
In September, London enjoys a delightful transition from summer's warmth to the crispness of autumn. With temperatures ranging from a minimum of 4°C (39°F) to a maximum of 28°C (83°F), the city experiences an inviting average of 15°C (59°F). This month marks a notable decrease compared to the summer heat, yet it retains a pleasant warmth, making it ideal for outdoor activities and exploring the vibrant streets. As the days begin to shorten, September's mild climate invites visitors to savor the beauty of London before the cooler months set in, blending the lingering warmth of summer with the first hints of fall.
September in London brings a moderate 45 mm (1.8 in) of precipitation, marking a gentle decline from the summer months' wetter spells. With about 10 rainy days, the month offers a balance of dry and damp conditions, making it a transitional period as the city moves from the warmth of summer to the cooler autumn air. This slight dip in both precipitation amount and frequency is reflective of the broader trend observed from June through September, where rainfall generally tapers off after reaching a peak in the earlier summer months. As the days shorten and temperatures cool, September presents Londoners with a mix of overcast skies and fleeting sunshine, setting the stage for the heavier rains that October typically brings.
As September rolls into London, humidity levels settle at a moderate 82%, reflecting a gradual transition from the more humid summer months. Following the peak of 91% in January and a slow decline through the spring to a relatively drier 71% in July, September sees a slight uptick as autumn approaches. This resurgence in humidity is a precursor to the wetter months ahead, notably October and November, when levels climb back up to 90% and 92% respectively. The change in humidity not only heralds the shift in seasons but also offers Londoners a lingering taste of summer's warmth before the chill of winter arrives.
As summer fades and September arrives in London, the UV Index reflects a shift in the season, landing at 6, which falls into the high exposure category. This increase from the more moderate ratings seen earlier in spring illustrates the lingering strength of the sun as warmer days persist. With an average burn time of just 25 minutes, it’s a reminder that while autumn is on the horizon, sunscreen should still be a staple in your outdoor plans. This trend showcases the transitional nature of UV exposure, guiding Londoners to remain vigilant in protecting their skin. For more detailed information about UV levels throughout the year, visit London UV Index.
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September in London marks a charming transition from the vibrant warmth of summer to the crispness of autumn, boasting an impressive 300 hours of sunshine. This month stands out as a delightful blend of lingering summer days and mild weather, bridging the gap between the sun-soaked July (404 hours) and the cooler October (241 hours). While September's sunshine diminishes compared to the peak of summer, it still shines brighter than the earlier months of the year like January (98 hours) and February (148 hours). This gradual decrease reflects the city's shifting seasons, offering Londoners a golden opportunity to savor outdoor adventures before the winter chill sets in.
In September, London enjoys a 29% chance of sunny weather, a figure that reflects a subtle shift from the summer months. As the city transitions from the warmth of August, where sunlight breaks through about 25% of the time, September maintains a similar probability. Notably, this month sees a considerable increase in sun compared to the dreary mid-winter months, which hover around 19% to 25%. While September may not boast the highest likelihood of sun — that title goes to the brighter April at 49% — it continues to offer a pleasant reprieve from the gloom that descends in the fall. Perfect for enjoying the last remnants of summer's warmth, September's sunny spells are a delightful gift before the autumn chill sets in.
As summer gives way to autumn, September in London sees a gradual shift in daylight duration, offering around 12 hours of sunlight. This marks a noticeable decline from the 16 hours enjoyed in the peak of summer during June and July. However, compared to the shorter days ahead, September still provides a comforting buffer before the onset of winter, where daylight dwindles to a mere 10 hours in October. This month serves as a gentle reminder of the changing seasons, with daylight steadily decreasing, yet still allowing for ample time to relish the lingering warmth and vibrant early autumn hues that London has to offer.
As September arrives in London, the city experiences a gentle breeze with an average wind speed of 3.3 m/s (7 mph), marking a continuation of the calmer summer months. This decline from a peak wind speed in early spring, where March recorded 4.4 m/s (10 mph), is indicative of a transitional phase as the warmth of summer gives way to the coolness of autumn. Throughout the year, winds remain relatively stable, with the briskest gusts typically seen in January and October, both reaching 4.4 m/s (10 mph). As we navigate through September, the soft winds create a serene backdrop for autumn strolls in the city, beckoning residents to enjoy the shifting scenery as the leaves begin to change.
The weather in London 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 London and find detailed weather information for every month.
September and January present contrasting weather patterns in London. In September, temperatures range from a mild 4°C (39°F) at night to a warm 28°C (83°F) during the day, with an average temperature of 15°C (59°F). The month also sees 45 mm (1.8 in) of precipitation over about 10 days, accompanied by a relatively high humidity of 82%. Conversely, January experiences much colder conditions, characterized by minimum temperatures dropping to -5°C (24°F) and daytime highs peaking at 14°C (58°F), leading to an average temperature of only 5°C (41°F). Rainfall is slightly higher at 54 mm (2.1 in) over the same number of days, coupled with increased humidity at 91%. For more detailed information about January weather, check out London weather in January.
In September, the weather tends to be relatively mild, with average temperatures ranging from a cool 4°C (39°F) at night to a pleasant maximum of 28°C (83°F) during the day, accompanied by a moderate humidity of 82%. In contrast, February experiences colder temperatures, where nighttime lows can drop to -5°C (23°F) and daytime highs reach only up to 18°C (65°F), alongside slightly higher humidity levels of 89%. Additionally, February sees a bit more precipitation, with around 53 mm (2.1 in) spread over 11 days compared to September’s 45 mm (1.8 in) over 10 days. For more details about February's weather, visit London weather in February.
In September, the weather tends to be milder, with temperatures ranging from a minimum of 4°C (39°F) to a maximum of 28°C (83°F) and an average of 15°C (59°F). The month sees about 45 mm (1.8 in) of precipitation, spread over approximately 10 days, and a humidity level of 82%. In contrast, March experiences cooler temperatures, with a minimum of -5°C (23°F) and an average of 7°C (46°F), while the maximum reaches 22°C (71°F). Precipitation is slightly higher at 54 mm (2.1 in) over about 13 days, accompanied by a higher humidity of 86%. For more detailed information about the weather conditions in March, check out London weather in March.
In September, temperatures show a broader range with a minimum of 4°C (39°F) and a maximum of 28°C (83°F), resulting in a pleasant average of 15°C (59°F). The month experiences slightly higher precipitation at 45 mm (1.8 in) over approximately 10 days, while humidity remains at 82%. In contrast, April typically starts cooler, with a minimum of -2°C (29°F) and an average temperature of 10°C (49°F), reaching a maximum of 26°C (80°F). Precipitation in April is slightly lower at 33 mm (1.3 in) across about 8 days, accompanied by a higher humidity of 85%. For more detailed information, check London weather in April.
September and May present distinct weather patterns as they transition between seasons. In September, temperatures range from a minimum of 4°C (39°F) to a maximum of 28°C (83°F), with an average of 15°C (59°F) and humidity levels around 82%. In contrast, May sees cooler temperatures, with a minimum of 1°C (35°F) and a maximum of 25°C (78°F), averaging 13°C (55°F) and a slightly lower humidity of 79%. Precipitation is relatively higher in May, totaling 62 mm (2.5 in) over 11 days, compared to September's 45 mm (1.8 in) over 10 days. For more details on May weather, you can check London weather in May.
When comparing the weather in September and June, several notable differences emerge. September experiences cooler temperatures, with a minimum of 4°C (39°F) and an average high of 28°C (83°F), while June typically has milder conditions, ranging from a minimum of 7°C (45°F) to a maximum of 31°C (89°F). Additionally, June tends to receive more precipitation, with 77 mm (3.0 in) over 9 days, compared to September's 45 mm (1.8 in) across 10 days. Humidity levels are relatively similar, with September at 82% and June slightly lower at 80%. For more detailed information on June weather, you can refer to London weather in June.
In a comparison of September and July weather, September presents a cooler profile with temperatures ranging from a minimum of 4°C (39°F) to a maximum of 28°C (83°F), while July boasts warmer conditions, with a minimum of 9°C (49°F) and temperatures peaking at 36°C (96°F). Although July experiences slightly higher precipitation at 64 mm (2.5 in) over 11 days compared to September's 45 mm (1.8 in) across 10 days, it also maintains a lower humidity level at 71% versus September's 82%. For more detailed insights, you can check London weather in July.
In comparing the weather between September and August, September experiences cooler temperatures, with a minimum of 4°C (39°F) and an average of 15°C (59°F), while August boasts warmer conditions, with a minimum of 8°C (47°F) and an average of 18°C (64°F). The maximum temperature in August can reach up to 34°C (93°F), significantly higher than September's maximum of 28°C (83°F). Additionally, September sees more days of rain, totaling about 10 days with 45 mm (1.8 in) of precipitation, compared to August's 12 days and 70 mm (2.7 in) of rainfall. Despite the slight increase in precipitation, August has a lower humidity level at 76%, whereas September's humidity rises to 82%. For more information, check out London weather in August.
In comparing the weather between September and October, a noticeable shift occurs as the temperatures drop and precipitation levels rise. September typically enjoys a wider temperature range with minimums around 4°C (39°F) and maximums reaching up to 28°C (83°F), averaging about 15°C (59°F). Conversely, October brings cooler conditions, with minimum temperatures dropping to 1°C (34°F) and a reduced maximum of 22°C (73°F), averaging 12°C (54°F). Additionally, October sees an increase in precipitation, totaling 84 mm (3.3 in) over 12 days, compared to September's 45 mm (1.8 in) over 10 days, and the humidity also rises to 90%. For more details, you can check London weather in October.
September and November present stark contrasts in weather. In September, temperatures range from a minimum of 4°C (39°F) to a maximum of 28°C (83°F), with an average of 15°C (59°F). It experiences moderate precipitation of 45 mm (1.8 in) over about 10 days, while humidity hovers around 82%. In contrast, November sees a notable drop in temperatures, with a minimum of -2°C (29°F) and a maximum of 16°C (62°F), leading to a cooler average of 8°C (47°F). Furthermore, November records slightly higher precipitation at 52 mm (2.0 in) across 11 days, accompanied by increased humidity at 92%. For more detailed information, visit London weather in November.
September and December present quite contrasting weather conditions. In September, temperatures range from a mild 4°C (39°F) at night to a warm average of 15°C (59°F) and a high of 28°C (83°F) during the day. The month sees around 45 mm (1.8 in) of precipitation spread over about 10 days, with humidity at 82%. In comparison, December experiences much colder weather, with temperatures dipping as low as -4°C (24°F) at night and averaging around 6°C (44°F), reaching a maximum of 14°C (58°F). Precipitation increases to 84 mm (3.3 in) occurring over 13 days, along with a higher humidity of 92%. For a more detailed look at December weather, visit London weather in December.
As summer gracefully transitions into autumn, September in London showcases a captivating mix of warmth and coolness. While temperatures can peak at a delightful 28°C, the average drops significantly, creating an engaging contrast with the balmy days of summer. Rainfall becomes more frequent, with about 10 days registering precipitation, making it a month where umbrellas become essentials. Humidity lingers around 82%, adding a slight heaviness to the air, but also nurturing the lush greenery of the city. For those looking to explore the varied climate of London throughout the year, the nuances of September present a unique experience. To delve deeper into how this month fits within London's overall climate, check out London Climate.