Last updated: August 27, 2025
September in Rjukan, Norway showcases a captivating transition into autumn, with temperatures ranging from a brisk -3°C (27°F) at night to a pleasant 21°C (69°F) during the day. The average temperature settles at a cool 6°C (44°F), inviting visitors to enjoy the crisp air and vibrant fall foliage. Travelers should prepare for a wet month, as 134 mm (5.3 in) of rain falls over 16 days, accompanied by high humidity levels of 86%. This unique blend of climate elements makes September an intriguing time to explore Rjukan’s stunning landscapes.
As September rolls into Rjukan, Norway, the transition towards autumn is palpable, marked by a notable shift in temperatures. The month greets visitors with a minimum temperature of -3°C (27°F), while an average of 6°C (44°F) provides a crispness in the air that hints at the chillier days ahead. Maxing out at 21°C (69°F), days can still carry a hint of summer warmth, particularly in the early parts of the month. Compared to the warmer summer months, September introduces cooler evenings and the observable onset of fall foliage, inviting outdoor exploration under vibrant skies. This blend of mildness and chill transforms Rjukan into a picturesque setting, ideal for those looking to experience the serene beauty of Norway as it prepares for winter.
In September, Rjukan, Norway, experiences a notable surge in precipitation, with 134 mm (5.3 in) of rain falling over 16 days, making it one of the wettest months of the year. This trend indicates a shift towards the wetter autumnal season, following the relatively drier summer months of June and August, which recorded 126 mm (5.0 in) and 113 mm (4.5 in), respectively. As temperatures begin to dip and the lush green landscape prepares for winter, September's precipitation sets the stage for increased moisture and vibrant fall colors, emphasizing the region's dynamic weather patterns and the transition from summer's warmth to autumn's embrace.
In Rjukan, Norway, the month of September brings a notable shift in humidity levels, climbing back up to 86% after the drier summer months. This increase marks a return to the more humid conditions characteristic of the late year, as humidity levels steadily rise from July's and August's relatively low averages of 74% and 78%, respectively. The trend indicates a gradual transition from the milder summer air to the damp chill that comes with autumn, setting the stage for the upcoming months where humidity frequently hovers around 92%. This pattern underscores Rjukan’s unique climate, characterized by significant seasonal variations that keep the landscape lush and vibrant.
As summer gives way to autumn in Rjukan, Norway, the UV Index experiences a notable shift. In September, it sits at a comfortable 4, categorizing exposure as moderate with a burn time of 30 minutes. This marks a decline from the peak of 7 observed during the sunnier months of June and July, reflecting the gradual retreat of summer's intensity. With May and August also showcasing high UV levels, September offers a more moderate environment, perfect for outdoor activities while still encouraging sun safety. For those planning their sun exposure, it's essential to stay informed and take precautions, particularly during the transitional months. Discover more about the UV Index in Rjukan for a safe and enjoyable experience outdoors: Rjukan UV Index.
UV Risk Categories
As the summer winds down, September in Rjukan, Norway, brings a delightful 248 hours of sunshine, a notable shift from the sun-drenched days of summer with a peak of 451 hours in July. This month marks a gentle transition, where daylight begins to recede, leading to shorter but still vibrant days. The sun-soaked warmth of May and June gives way to the crispness of autumn, yet September retains a generous amount of sunshine, inviting outdoor adventures amid the changing foliage. Despite a decline compared to the bustling days of summer, this month still offers a significant brightness that echoes the lingering warmth of the season, perfectly encapsulating the beauty of an autumnal Norway.
In Rjukan, Norway, the likelihood of sunny weather takes a notable dip in September, with only a 20% chance of sunshine. This trend follows the warmer summer months, where sunshine is more frequent, peaking in April at 56%, before gradually declining. As autumn approaches, the chances of sunny days continued to decrease, reflecting the transition into cooler, cloudier seasons. Interestingly, while July and August offer a modest 40% and 33% sun probability respectively, September stands out as the month where sunny days are least likely, marking the arrival of autumn's overcast skies.
As summer fades into autumn, September in Rjukan, Norway, sees a notable transition in daylight duration, where the sun graces the sky for approximately 12 hours each day. This marks a gentle decline from the sun-drenched heights of June, which boasts an impressive 18 hours of daylight. The trend continues from August's still-abundant 15 hours, signaling the gradual shift towards the shorter days of fall and winter. With October right around the corner, where daylight further shrinks to 10 hours, September serves as a beautiful bridge between the long, vibrant summer days and the cozy, introspective winter months ahead.
As September arrives in Rjukan, Norway, the wind begins to pick up slightly, with an average speed of 2.8 m/s (6 mph). This marks a subtle increase from the calmer winds of the summer months, where speeds hovered around 2.5 m/s (6 mph) in August. Interestingly, this trend of gentle escalation continues into the fall; October sees winds reach 3.4 m/s (8 mph), hinting at a seasonal shift. Overall, while Rjukan experiences predominantly light breezes throughout the year, the gradual uptick in September signals the approach of more invigorating autumn winds, adding a fresh edge to the crisp air and scenic surroundings.
Weather in Rjukan varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Rjukan, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, temperatures in Rjukan range from a chilly -3°C (27°F) at night to a pleasant maximum of 21°C (69°F) during the day, averaging around 6°C (44°F). With 134 mm (5.3 in) of precipitation over 16 days, the month is relatively wet, coupled with high humidity at 86%. In contrast, January sees much harsher conditions, as the temperature drops significantly, with nighttime lows reaching -25°C (-13°F) and daily highs only reaching 5°C (42°F) for an average of -6°C (21°F). Precipitation decreases to 68 mm (2.7 in) over 11 days, and humidity remains elevated at 93%. For a deeper insight into January weather specifics in Rjukan, you can check out this link: Rjukan weather in January.
September and February present stark contrasts in weather conditions. In September, temperatures range from a chilly minimum of -3°C (27°F) to a warm maximum of 21°C (69°F), with an average of 6°C (44°F). The month experiences significant rainfall, totaling 134 mm (5.3 in) over about 16 days, coupled with a relatively high humidity of 86%. In contrast, February sees much colder temperatures, with a minimum of -25°C (-13°F) and an average temperature of -7°C (20°F), reaching a maximum of only 6°C (43°F). February also brings less precipitation, measuring 73 mm (2.9 in) over 13 days, but the humidity is slightly higher at 91%. For a closer look at February weather in Rjukan, you can visit Rjukan weather in February.
When comparing the weather in September and March, notable differences emerge. September typically features a milder temperature range, with minimums around -3°C (27°F) and average highs reaching 21°C (69°F), alongside higher precipitation of 134 mm (5.3 in) over 16 days. This results in a humid atmosphere, with humidity levels around 86%. In contrast, March is much colder, starting with minimum temperatures as low as -24°C (-11°F) and average highs peaking at just 12°C (53°F). The total precipitation in March is significantly lower at 75 mm (2.9 in) spread over 13 days, and humidity remains slightly elevated at 88%. For a more detailed look at the weather patterns in March, you can visit Rjukan weather in March.
When comparing the weather in September and April, a noticeable difference can be seen in both temperature and precipitation. September offers a wider temperature range, with minimums of -3°C (27°F) and maximums reaching up to 21°C (69°F), resulting in an average temperature of 6°C (44°F). In contrast, April experiences colder temperatures, with minimums dropping to -19°C (-2°F) and maximums peaking at 15°C (59°F), leading to an average of only -1°C (30°F). Additionally, September sees significantly higher precipitation, totaling 134 mm (5.3 in) over 16 rainy days, whereas April has only 51 mm (2.0 in) of rainfall spread across 8 days. The humidity levels are also comparable, with September at 86% and April slightly lower at 83%. For more details about the weather in April, you can check Rjukan weather in April.
When comparing the weather in September and May, it's clear that both months exhibit distinct characteristics. September's temperatures range from a chilly minimum of -3°C (27°F) to a comfortable maximum of 21°C (69°F), with an average of 6°C (44°F). In contrast, May presents slightly cooler temperatures, with a minimum of -14°C (7°F), an average of 5°C (40°F), and a similar maximum of 21°C (70°F). Precipitation levels are higher in September, totaling 134 mm (5.3 in) over 16 days, compared to May's 88 mm (3.5 in) across 12 days. Humidity is also notably higher in September at 86%, while May has a more moderate 75%. For a closer look at weather specifics for Rjukan during May, you can visit Rjukan weather in May.
When comparing the weather in September and June, notable differences emerge. September experiences a wider temperature range, with minimums dropping to -3°C (27°F) and maximums reaching up to 21°C (69°F), while June has milder conditions, with minimums at -1°C (30°F) and maximums at 23°C (74°F). Precipitation levels are quite similar, with September receiving 134 mm (5.3 in) over 16 days, compared to June's 126 mm (5.0 in) over 14 days. Additionally, September tends to be more humid, at 86%, compared to June's 74% humidity. For more detailed insights into June weather, visit Rjukan weather in June.
In comparing the weather between September and July, we see distinct differences in temperature and humidity. September tends to be cooler, with minimum temperatures dipping to -3°C (27°F) and an average of 6°C (44°F), while July enjoys milder conditions, with a minimum of 0°C (33°F) and an average of 12°C (53°F). Additionally, July boasts a higher maximum temperature of 25°C (77°F), making it the warmest month of the year, whereas September’s maximum reaches only 21°C (69°F). Precipitation levels are slightly more pronounced in September, with 134 mm (5.3 in) over 16 days, compared to July’s 114 mm (4.5 in) over 14 days. Moreover, September experiences a greater humidity level of 86%, in contrast to July’s 74%. For more detailed information about July weather, you can visit Rjukan weather in July.
In comparing the weather between September and August, we can see a notable drop in average temperatures. September exhibits a minimum temperature of -3°C (27°F) and an average of 6°C (44°F), while August remains slightly warmer with a minimum of -1°C (30°F) and an average of 10°C (50°F). The maximum temperatures are also marginally higher in August, reaching 22°C (72°F) compared to September's 21°C (69°F). Additionally, September experiences more precipitation, totaling 134 mm (5.3 in) over 16 days, compared to August's 113 mm (4.5 in) over 17 days. This increase in rainfall in September, coupled with a higher humidity level of 86% compared to August's 78%, contributes to a noticeably cooler and wetter atmosphere as summer transitions into autumn. For more details, you can check Rjukan weather in August.
September and October present notable contrasts in weather patterns. September experiences milder temperatures, with a minimum of -3°C (27°F) and an average of 6°C (44°F), peaking at a comfortable 21°C (69°F). In contrast, October sees a significant drop, with minimum temperatures plummeting to -15°C (6°F) and an average of just 2°C (35°F). Both months are relatively wet, but October has slightly higher precipitation at 143 mm (5.6 in) over 19 days, compared to September's 134 mm (5.3 in) over 16 days. Humidity is also higher in October at 92%, compared to September's 86%. For more detailed insights on October's weather, check out Rjukan weather in October.
In September, the weather is relatively mild, with temperatures ranging from a minimum of -3°C (27°F) to a maximum of 21°C (69°F) and an average of 6°C (44°F). The month sees considerable precipitation at 134 mm (5.3 in) over 16 days, with high humidity at 86%. In contrast, November brings a sharp drop in temperatures, with a minimum of -26°C (-14°F) and a maximum of 9°C (49°F), yielding an average temperature of -3°C (27°F). While precipitation decreases slightly to 112 mm (4.4 in) over the same number of days, humidity rises to 92%. The significant temperature shift and increased humidity make November feel much colder compared to September. For more detailed insights, you can check Rjukan weather in November.
September and December offer starkly contrasting weather conditions. In September, temperatures range from a mild minimum of -3°C (27°F) to a comfortable maximum of 21°C (69°F), with an average of 6°C (44°F). The month experiences significant precipitation, with 134 mm (5.3 in) over 16 days, while humidity sits at a relatively high 86%. In contrast, December plunges into much colder temperatures, with lows reaching -22°C (-8°F) and an average of -6°C (22°F), only rising to a maximum of 5°C (42°F). December also sees a lower total precipitation of 119 mm (4.7 in) across 18 days, but the air is notably more humid, with a humidity level of 92%. For those curious about December weather specifics, check out Rjukan weather in December.
As September unfolds in Rjukan, the landscape transforms with the arrival of crisp temperatures and the subtle warmth of early autumn. Unlike the warmer summer months, nights grow cooler, dipping to frosty lows, making the average daytime temperature feel refreshingly brisk. While September does bring about an increase in precipitation, contributing to a more humid atmosphere, it also creates a vibrant backdrop for the changing leaves, with about half the month seeing some rain. This combination of cooler weather and moisture sets the stage for stunning fall scenery, perfectly captured in the picturesque surroundings of Rjukan. For a deeper dive into the yearly climate trends, be sure to explore Rjukan Climate.