Last updated: March 17, 2025
September in Harrow on the Hill brings a delightful blend of early autumn charm and late summer warmth. With maximum temperatures soaring to 28°C (83°F) and an average of 15°C (59°F), the month offers a pleasant climate for outdoor activities. However, as the season transitions, the temperature may dip to a minimum of 4°C (39°F), reminding us of the approaching fall. Rainfall measures 45 mm (1.8 in) across approximately 10 days, contributing to a relatively high humidity level of 82%. This dynamic weather makes September a captivating time to experience the beauty of Harrow, with its rich landscapes and vibrant community.
As September arrives in Harrow on the Hill, temperatures begin to exhibit a refreshing transition from the summer heat. The minimum temperature of 4°C (39°F) gradually pulls away from the warmer months, while the average settles at a comfortable 15°C (59°F), making it ideal for outdoor activities. With a maximum of 28°C (83°F), the warmth lingers just enough to embrace the last remnants of summer. This month signifies a gradual cooling, as daylight hours shorten and autumn colors start to emerge, inviting locals and visitors alike to relish in the crisp, pleasant days ahead while bidding farewell to the summer's peak.
September in Harrow on the Hill sees a notable shift in precipitation patterns, with average rainfall at 45 mm (1.8 in) over 10 rainy days. This marks a decline from the wetter summer months, particularly August, which experienced 70 mm (2.7 in) over 12 days. The relatively mild September rainfall signals the onset of autumn, as the skies begin to cloud and showers become more frequent. Compared to the early summer months like June, which recorded 77 mm (3.0 in), September represents a transitional phase, paving the way to even wetter months ahead, particularly October when precipitation often peaks. This downward trend in rainfall emphasizes the gradual shift toward the cooler, more drizzly season that characterizes the UK climate.
As summer transitions to autumn in Harrow on the Hill, September brings a noticeable shift in humidity levels, registering at 82%. This moderate figure reflects a gradual increase from the drier summer months, where July enjoyed a low of 71% and August raised it slightly to 76%. The return of moisture in September hints at the approach of the wetter months ahead, with October and November anticipated to see much higher levels, peaking at 90% and 92% respectively. This trend underscores the region's characteristic dampness as the year draws to a close, contrasting sharply with the lighter, more comfortable humidity of late spring.
As September unfolds in Harrow on the Hill, the UV Index reflects a transition towards the softer rays of autumn with a rating of 6, categorizing it as high exposure. This marks a slight decrease from the blazing summer months, where July and June reached a peak of 8, indicating very high exposure with minimal burn times of just 15 minutes. In contrast, September maintains a 25-minute burn time, suggesting that while the sun is still strong, it’s time to adjust your sun protection strategies. As we move into October, the UV Index is expected to decline further to 4, signaling a moderation in exposure. For continuous updates on sun safety and UV levels, visit Harrow on the Hill UV Index.
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As September unfolds in Harrow on the Hill, the sun continues to grace the landscape with 300 hours of sunshine, a notable amount that reflects the lingering warmth of summer. This month stands as a transition, with daylight hours gradually tapering off after the peak of 404 hours in July. Reflecting on the annual pattern, there's a steady rise in sunlight from January's meager 98 hours, culminating in the vibrant months of April and May, where the sun shines its brightest. However, as autumn approaches, the decrease in daylight hours becomes evident, with October anticipating 241 hours. Thus, September offers a delightful balance—basking in the tail end of summer's glow while hinting at the cozy charm of the upcoming fall.
September in Harrow on the Hill offers a moderate chance of sunny weather, with approximately 29% likelihood of sunshine. Notably, this marks a return to a more favorable trend compared to the summer months, where July peaks at 38%, followed by a decline in August. As autumn approaches, September balances between the lingering warmth of summer and the cooler fall days, making it a delightful month for enjoying the outdoors. While the chance of sun has dipped from the springtime highs of 49% in April, it remains a reliable window for those looking to savor some sunshine before the dreary winter months settle in, which start to see much lower probabilities of sunny weather.
As September unfolds in Harrow on the Hill, daylight begins to wane, offering a gentle transition from the vibrant summer months. With 12 hours of daylight, this month marks a noticeable shift, stepping down from August's lush 14 hours. The trend of decreasing daylight is set against a backdrop of gradual light increases from the depths of winter, where January offers a mere 8 hours, to the summer peak in June and July, boasting 16 hours of sun. As autumn approaches, September serves as a bridge, where the days still hold on to warmth while subtly preparing for the cozy embrace of October's 10 hours, making it a time of reflection and change in the natural rhythm of life.
As summer gently wanes, September in Harrow on the Hill embraces a soft breeze, with an average wind speed of 3.3 m/s (7 mph). This marks a distinct shift from the warmer months, where gusts were slightly brisker in June and July, averaging around 3.1 m/s and 3.3 m/s, respectively. The transition to September signals a quieter time as winds mellow, offering a soothing backdrop to the early autumn landscape. With October's winds expected to pick up to 4.4 m/s (10 mph), September serves as a tranquil prelude, a moment where the air feels less hurried and the waning warmth invites nostalgic reflections of summer's vibrancy.
The weather in Harrow on the Hill 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 Harrow on the Hill and find detailed weather information for every month.
September and January present 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) during the day, peaking at a high of 28°C (83°F). The month experiences 45 mm (1.8 in) of precipitation over approximately 10 days, with humidity around 82%. In stark contrast, January features much colder temperatures, with a minimum of -5°C (24°F), an average of 5°C (41°F), and a maximum of only 14°C (58°F). The precipitation slightly increases to 54 mm (2.1 in) across the same number of days, while humidity rises to 91%. This shift in temperature and moisture illustrates the transition from early autumn to mid-winter conditions. For more details, check out Harrow on the Hill weather in January.
September and February showcase contrasting weather patterns. September typically enjoys milder temperatures, ranging 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 relatively lower precipitation, totaling about 45 mm (1.8 in) over approximately 10 days and a humidity level at 82%. In contrast, February is much colder, with temperatures dipping down to a minimum of -5°C (23°F) and only reaching a maximum of 18°C (65°F), resulting in an average temperature of 6°C (43°F). February also sees slightly more precipitation, around 53 mm (2.1 in) over 11 days, and a higher humidity level of 89%. For more detailed information, you can check Harrow on the Hill weather in February.
September and March exhibit distinct weather patterns, reflecting the 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), indicating a generally mild climate. The month sees about 45 mm (1.8 in) of precipitation over approximately 10 days, accompanied by a humidity level of 82%. In contrast, March experiences cooler conditions, with temperatures dipping to a minimum of -5°C (23°F) and reaching a maximum of 22°C (71°F), resulting in an average of 7°C (46°F). This month also has a slightly higher precipitation total of 54 mm (2.1 in) over about 13 days, along with a humidity of 86%. For more detailed insights, check out Harrow on the Hill weather in March.
September and April showcase distinct weather characteristics. In September, temperatures range from a low of 4°C (39°F) to a comfortable high of 28°C (83°F), with an average of 15°C (59°F). The month experiences about 45 mm (1.8 in) of precipitation over roughly 10 days, accompanied by relatively high humidity at 82%. In contrast, April starts off cooler, with temperatures dipping as low as -2°C (29°F) and peaking at 26°C (80°F), averaging around 10°C (49°F). This month sees slightly less rainfall at 33 mm (1.3 in) over about 8 days, and an increase in humidity at 85%. For more detailed insights, check out Harrow on the Hill weather in April.
When comparing the weather in September and May, September generally sees warmer temperatures, with an average of 15°C (59°F) and a maximum reaching 28°C (83°F), compared to May's average of 13°C (55°F) and maximum of 25°C (78°F). Precipitation levels are slightly lower in September, totaling 45 mm over about 10 days, whereas May experiences 62 mm of rain over 11 days. Additionally, humidity is marginally higher in September at 82%, compared to May's 79%. For more detailed insights on May weather, you can check Harrow on the Hill weather in May.
When comparing the weather in September and June, September tends to be slightly cooler, with average temperatures ranging from a minimum of 4°C (39°F) to a maximum of 28°C (83°F), compared to June's range of 7°C (45°F) to 31°C (89°F). While June enjoys warmer and sunnier days, it also experiences more precipitation, with an average of 77 mm (3.0 in) over about 9 days, compared to September's 45 mm (1.8 in) over 10 days. Humidity levels are similar in both months, hovering around 80-82%. For detailed insights into June weather, you can check Harrow on the Hill weather in June.
When comparing the weather in September and July, notable differences emerge. September experiences milder temperatures with a minimum of 4°C (39°F), an average of 15°C (59°F), and a maximum of 28°C (83°F). In contrast, July is warmer, with temperatures ranging from a minimum of 9°C (49°F) to a maximum of 36°C (96°F) and an average of 18°C (65°F). Precipitation levels are also higher in July, totaling 64 mm (2.5 in) over 11 days, compared to September's 45 mm (1.8 in) over 10 days. Additionally, September has a higher humidity level at 82%, while July maintains a lower humidity of 71%. For more detailed insights into July weather patterns, visit Harrow on the Hill weather in July.
The weather in September shows a noticeable shift compared to August. September experiences cooler temperatures, with a minimum of 4°C (39°F) and a maximum of 28°C (83°F), in contrast to August’s higher range of 8°C (47°F) to 34°C (93°F). While humidity is slightly higher in September at 82%, it still feels less oppressive than the warmer August days, which had an average humidity of 76%. Additionally, September sees a decrease in both precipitation and rainy days, recording 45 mm (1.8 in) over 10 days, compared to August's 70 mm (2.7 in) over 12 days. For more specific details, you can check Harrow on the Hill weather in August.
In September, the weather is generally 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 receives about 45 mm (1.8 in) of precipitation over approximately 10 days, accompanied by a humidity level of 82%. In contrast, October brings cooler temperatures, with a minimum of 1°C (34°F), an average of 12°C (54°F), and a maximum of 22°C (73°F). Rainfall increases significantly to 84 mm (3.3 in) over about 12 days, coupled with a higher humidity of 90%. For more detailed insights into October weather, you can check Harrow on the Hill weather in October.
September and November present quite a contrast in weather conditions. In September, temperatures are milder, with averages around 15°C (59°F) and highs peaking at 28°C (83°F), while November sees a significant drop, with an average temperature of 8°C (47°F) and maximums reaching only 16°C (62°F). Additionally, September experiences slightly less precipitation at 45 mm (1.8 in) over about 10 days, compared to November’s 52 mm (2.0 in) across 11 days. Humidity levels also increase in November, reaching 92% compared to September's 82%. For more details, check out Harrow on the Hill weather in November.
September weather is notably warmer, with average temperatures around 15°C (59°F) and highs reaching up to 28°C (83°F), while December experiences chillier conditions, with an average temperature of only 6°C (44°F) and a maximum of 14°C (58°F). Precipitation also differs between the two months; September sees about 45 mm (1.8 in) spread over 10 days, whereas December has nearly double the rainfall at 84 mm (3.3 in) over 13 days, reflecting the shift towards a wetter winter season. Additionally, humidity rises in December to 92%, compared to September's 82%, adding to the cold, damp feel of the winter month. For more specific details on December weather conditions, visit Harrow on the Hill weather in December.
As the summer draws to a close, September in Harrow on the Hill ushers in a transition marked by a refreshing blend of warm days and cool evenings. Temperatures can soar to a pleasant 28°C, but the average hovers around a comfortable 15°C, inviting outdoor activities while hinting at the crispness of autumn. With 82% humidity and about 10 days of rainfall totaling 45 mm, this month stands out with less predictability in weather compared to the stable summer months. September serves as a reminder of nature's fickle beauty, making it an ideal time to explore the stunning landscapes. For a deeper dive into the weather patterns, check out the full details on the Harrow on the Hill Climate.