Last updated: August 27, 2025
September in Trondheim, Norway is characterized by a mild climate that transitions from the warmth of summer to the coolness of autumn. The maximum temperature can reach 22°C (71°F), while the average hovers around a comfortable 11°C (52°F), dipping to a minimum of 2°C (36°F) on cooler days. This month also witnesses significant rainfall, with a total of 124 mm (4.9 in) spread across 17 days, contributing to a high humidity level of 90% that adds to the crispness in the air. Visitors can expect a blend of cozy, overcast days and occasional sunny intervals, making it an enchanting time to explore the city's natural beauty.
As September arrives in Trondheim, Norway, the city begins its gentle transition into autumn. With temperatures ranging from a minimum of 2°C (36°F) to a maximum of 22°C (71°F), it offers a refreshing respite from the summer heat. The average temperature settles at 11°C (52°F), making it the perfect time for locals and travelers alike to enjoy the stunning fall foliage. This month signifies a notable drop in temperature compared to the warm summer months, yet it's still comfortably mild, inviting outdoor activities and exploration. As daylight shortens, the crisp air heralds the changing seasons, hinting at the colder months ahead, while preserving the charm of late summer warmth.
In September, Trondheim experiences a noticeable uptick in precipitation, with rainfall amounting to 124 mm (4.9 in) over the month, making it one of the wettest periods of the year. This surge is reflected in the 17 days of rain, marking an increase from the preceding months and setting the stage for the arrival of autumn. The trend of heightened precipitation continues into October, suggesting that as summer fades, Trondheim braces for more frequent rain, contributing to the region's lush landscapes. Overall, September serves as a pivotal transition, with rain heralding the seasonal shift while underscoring the city’s characteristic wet climate.
As September settles in Trondheim, Norway, the humidity begins to shift slightly after the summer months, hovering around 90% this time of year. This marks a subtle uptick from August's 88%, indicating a gradual transition towards the colder and more humid months ahead. Throughout the year, Trondheim experiences its highest humidity in the winter, peaking at 97% in December, while the summer months show a slight decline, with July and June each maintaining a comfortable 81%. This pattern highlights a marked seasonal rhythm where the crisp autumn air invites a return to dampness, setting the stage for the wetter fall and winter ahead. As the months progress, residents can expect the humidity to rise again, wrapping the city in a cool, misty embrace.
In September, Trondheim experiences a moderate UV Index of 3, indicating a gradual shift from the higher values of summer months. As the days shorten and the sun's intensity wanes, the burn time remains consistent at 30 minutes, reminding residents and visitors alike that while it's safer to be outdoors, sun protection is still essential. This trend of reduced UV exposure marks a welcome transition towards the cozy autumn season, following the high UV levels of June and July, which both reached 6. By comparing September's data to earlier months, it becomes clear that while UV radiation is dropping, being mindful of sun safety remains crucial. For more detailed information about UV levels and safety, visit Trondheim UV Index.
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As autumn begins to settle in Trondheim, September brings a refreshing transition with 258 hours of sunshine. This marks a noticeable decline from the long, sunlit days of summer, which boasted a peak of 431 hours in July. The gradual reduction in daylight is evident as the city shifts from May's vibrant 419 hours to the more mellow ambiance of early autumn. While the days grow shorter, September still offers a generous amount of sunlight compared to the winter months ahead, where sunshine plummets to just 60 hours in December. This blend of fading summer warmth and the promising embrace of fall creates a uniquely inviting atmosphere, perfect for enjoying Trondheim's stunning landscapes.
In Trondheim, Norway, the likelihood of sunny weather takes a noticeable dip as September rolls in, with a mere 20% chance of sunshine. This trend marks a decline from the summer months, as July and August each maintain a more promising 28% chance of bright days. As the warm embrace of summer yields to the crispness of autumn, the sun seems to retreat, a pattern echoed in the surrounding months — notably, October lingers at just 14%. The shifting seasons highlight the fleeting nature of clear skies in Trondheim, where the onset of fall invites an air of wistful contemplation amid the gathering clouds.
As summer fades in Trondheim, September brings a gentle transition with 12 hours of daylight—a noticeable but still generous amount compared to the bleak winter months ahead. Following the sun-kissed days of July and August, where daylight peaked at 19 and 16 hours respectively, September serves as a bridge, gradually leading the city from the long, bright summer nights into autumn's shorter days. This month signifies a decline in daylight, hinting at the colder months to come, and sets the stage for the stark contrast of October's 9 hours. As the light begins to wane, residents and visitors can savor the softer illumination that September offers, encapsulating the serene beauty of autumn's approach.
As September arrives in Trondheim, Norway, the wind begins to pick up a gentle rhythm, with an average speed of 2.5 m/s (6 mph). This mark follows a summer where wind speeds hovered on the calmer side, notably dropping to 1.9 m/s (4 mph) in both May and June. However, the transition into autumn brings a breath of fresh air, as September's winds are slightly stronger than its late summer predecessors. Looking ahead, October and November maintain this trend with consistent speeds of 2.7 m/s (6 mph) and 2.5 m/s (6 mph), respectively. This gradual increase reflects the seasonal shift, offering a compelling reminder of nature's ebb and flow as it prepares for the colder months ahead.
Weather in Trondheim varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Trondheim, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present strikingly contrasting weather conditions. In September, temperatures range from a mild 2°C (36°F) at night to a pleasant 22°C (71°F) during the day, with an average of 11°C (52°F). This month experiences significant rainfall, with 124 mm (4.9 in) over 17 days and humidity levels at a comfortable 90%. Conversely, January brings much colder temperatures, dipping as low as -18°C (-1°F) and typically averaging -2°C (29°F), peaking at 12°C (53°F). Although precipitation is lower at 94 mm (3.7 in) over 14 days, the humidity is slightly higher at 96%, contributing to a biting chill. For a detailed look at the winter climate, check out Trondheim weather in January.
September and February present stark contrasts in weather conditions. In September, temperatures range from a mild 2°C (36°F) at night to a pleasant max of 22°C (71°F) during the day, accompanied by significant rainfall of 124 mm (4.9 in) across 17 days. The high humidity of 90% makes the air feel quite moist.
In contrast, February's climate is much harsher, with temperatures plummeting to a minimum of -25°C (-12°F) and averaging around -2°C (29°F). The maximum temperature barely reaches 10°C (50°F), and precipitation, although lower at 75 mm (3.0 in), occurs over 13 days. The humidity also remains high at 94%, contributing to the bone-chilling cold. For more details, check out Trondheim weather in February.
In comparing the weather between September and March, notable differences emerge. September typically enjoys milder temperatures, with a minimum of 2°C (36°F) and an average of 11°C (52°F), peaking at 22°C (71°F). In contrast, March is much colder, starting at a minimum of -24°C (-12°F) and averaging just 1°C (33°F), with a maximum of 14°C (58°F). Additionally, while September sees a significant amount of precipitation at 124 mm (4.9 in) over 17 days, March's precipitation is slightly lower at 111 mm (4.4 in) but occurs over an additional day. Humidity levels are quite similar, with September at 90% and March slightly higher at 91%. For more detailed weather information, you can check Trondheim weather in March.
In comparing the weather between September and April, notable differences emerge. September tends to offer milder temperatures, with an average of 11°C (52°F) and a maximum reaching 22°C (71°F), whereas April starts off cooler, averaging 5°C (40°F) and experiencing minimums that can drop as low as -12°C (11°F). While both months see a similar number of rainy days—17 in September and 16 in April—September experiences higher overall precipitation at 124 mm (4.9 in) compared to April's 93 mm (3.7 in). Moreover, humidity levels are slightly higher in September at 90%, while April is at 86%. For those interested in learning more about the weather specifics in April, you can check out Trondheim weather in April.
September and May present distinct weather experiences characterized by differences in temperature, precipitation, and humidity. In September, temperatures range from a minimum of 2°C (36°F) to a maximum of 22°C (71°F), with an average of 11°C (52°F). The month sees substantial rainfall, totaling 124 mm (4.9 in) over approximately 17 days, contributing to a high humidity level of 90%. In contrast, May offers slightly cooler conditions with temperatures ranging from -2°C (28°F) to 27°C (80°F) and an average of 9°C (49°F). Precipitation is lower at 70 mm (2.7 in) over about 15 days, and humidity is somewhat less, at 83%. This makes May a drier and slightly warmer month compared to the wetter and cooler September. For more detailed insights, you can visit Trondheim weather in May.
In comparing the weather of September to that of June, notable differences emerge. September experiences cooler temperatures, with a minimum around 2°C (36°F) and a maximum of 22°C (71°F), while June enjoys warmer conditions, boasting a higher minimum of 3°C (37°F) and a maximum that can reach up to 32°C (89°F). Additionally, September tends to be wetter with average precipitation of 124 mm (4.9 in) over 17 days, compared to June's 89 mm (3.5 in) spread across 14 days. Humidity levels are also higher in September at 90%, compared to June's 81%. For a more detailed look at the weather during this month, visit Trondheim weather in June.
In September, the weather in Trondheim experiences cooler temperatures compared to July, with a minimum of 2°C (36°F) and an average of 11°C (52°F), while July sees a higher minimum of 5°C (41°F) and an average of 16°C (60°F). July boasts warmer maximum temperatures, reaching up to 33°C (92°F), in contrast to September's milder peak of 22°C (71°F). The amount of precipitation also differs, with September receiving 124 mm (4.9 in) over 17 days, while July experiences less rain at 88 mm (3.5 in) across 16 days. Additionally, September has higher humidity levels at 90%, compared to July's 81%. For more detailed information, you can explore Trondheim weather in July.
September weather in Trondheim is notably cooler than August, with minimum temperatures dropping to 2°C (36°F) compared to August's 4°C (40°F). The average temperature also decreases from 14°C (58°F) in August to 11°C (52°F) in September, while the maximum temperature is significantly lower at 22°C (71°F) compared to August's peak of 31°C (88°F). While precipitation levels are slightly higher in September at 124 mm (4.9 in) over 17 days, humidity stays relatively constant, rising to 90% from August's 88%. For a detailed comparison of August weather, you can check out Trondheim weather in August.
September and October present distinct shifts in weather patterns. In September, temperatures range from a mild 2°C (36°F) at night to a comfortable 22°C (71°F) during the day, with an average temperature of 11°C (52°F). The month sees significant rainfall, with 124 mm (4.9 in) distributed across 17 days and a high humidity level of 90%.
Conversely, October experiences cooler temperatures, with nighttime lows dropping to -4°C (24°F) and an average temperature of 6°C (44°F). Although the maximum temperature hovers around 21°C (70°F), it is accompanied by slightly lower total precipitation at 123 mm (4.8 in) over 19 days and an increase in humidity to 93%. For a detailed overview of what to expect, you can check out Trondheim weather in October.
September weather tends to be milder compared to November, with temperatures ranging from a minimum of 2°C (36°F) to a maximum of 22°C (71°F), offering an average of 11°C (52°F). In contrast, November sees much colder conditions, with temperatures dropping to a minimum of -14°C (7°F) and reaching a maximum of only 14°C (57°F), resulting in a much lower average temperature of around 2°C (36°F). While September experiences more rainfall with 124 mm (4.9 in) over 17 days, November has slightly less precipitation at 88 mm (3.5 in) over 13 days. Additionally, November's humidity levels are generally higher at 95%, compared to 90% in September, making the air feel even colder. For more detailed insights into November’s climate, you can check Trondheim weather in November.
September and December weather in Trondheim present a stark contrast in temperature and conditions. In September, temperatures range from a minimum of 2°C (36°F) to a comfortable maximum of 22°C (71°F), with an average of 11°C (52°F). The month experiences significant rainfall, averaging 124 mm (4.9 in) over 17 days and a relatively high humidity of 90%. Conversely, December brings much colder conditions, with a temperature range from a chilling -16°C (3°F) to a maximum of 10°C (50°F), averaging around -1°C (31°F). Although the precipitation is slightly lower at 105 mm (4.1 in) over 15 days, the humidity rises to 97%. For a detailed look at December weather specifically, you can refer to Trondheim weather in December.
As September unfolds in Trondheim, the transition from summer to autumn becomes palpable, characterized by cooler temperatures and increased humidity. While the maximum temperatures still reach a pleasant 22°C, the average dips to a crisp 11°C, bringing a refreshing chill to the air. The month is also marked by significant rainfall, with nearly half the days seeing precipitation, making it one of the wetter months of the year. This blend of mild warmth and frequent showers sets September apart from the sunnier, dryer summer months, creating a vibrant atmosphere as nature prepares for the seasonal shift. For a deeper dive into what Trondheim's weather has in store, check out Trondheim Climate.