September Weather in Coimbra, Portugal

Last updated: February 24, 2025

Experience the diverse September weather in Coimbra, Portugal, where temperatures can soar to a maximum of 37°C (98°F) while averaging a comfortable 20°C (69°F). As the month progresses, nighttime lows can drop to a refreshing 9°C (49°F), offering a pleasant respite from the daytime heat. Expect light precipitation, with a total of 36 mm (1.4 in) spread across approximately 4 days, while humidity rests at a moderate 71%. This blend of warmer days and cooler evenings makes September an ideal time to explore the rich cultural heritage and stunning landscapes of Coimbra.

September Temperature in Coimbra

In September, Coimbra experiences a delightful transition as summer winds down, with temperatures ranging from a minimum of 9°C (49°F) to a maximum of 37°C (98°F). The average temperature is a comfortable 20°C (69°F), providing a perfect balance for outdoor activities and leisurely exploration of the city’s historic charm. As the intense heat of August fades, visitors can enjoy pleasant days that still capture the lingering warmth of summer, while evenings become cooler and more refreshing. This month marks a significant shift, setting the stage for the mild and inviting autumn months that follow, making it an ideal time to experience Coimbra's rich culture and stunning landscapes.

September Weather in Coimbra: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Coimbra, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec485254586366707068635552
Data source: Temperature data for Coimbra generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Coimbra

As September unfolds in Coimbra, Portugal, it marks a transition from the dry summer months into the more temperate autumn season. With 36 mm (1.4 in) of precipitation spread over four days, the month brings a welcome relief from the heat and a gentle start to the rainy season. This amount is a noticeable increase compared to the virtually dry spells of July and August, which saw only a combined total of 17 mm (0.7 in) of rain over just three days. However, September remains relatively mild in terms of rainfall when juxtaposed with the influx anticipated in October and November, which often deliver much more significant precipitation. Overall, this shift underscores Coimbra's dynamic climate, where late summer dryness gives way to the rejuvenating rains of early autumn, setting the stage for the rich, lush landscapes to come.

September Precipitation Trends in Coimbra

The chart displays monthly precipitation patterns in Coimbra, with values for each month alongside September's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec63881171205731893691126112
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Coimbra

In September, Coimbra experiences a notable shift in humidity, with levels around 71%. This marks a gradual increase from the summer months of July and August, where humidity dropped to 63% and 64%, respectively. As autumn approaches, the air begins to feel more humid, indicative of the seasonal transition. This trend is consistent with the overall annual pattern in Coimbra, where humidity levels peak in the winter months, reaching heights of 87% in January and December. The mild, yet increasingly damp atmosphere in September sets the stage for the wetter and cooler months ahead, creating a refreshing environment for both locals and visitors.

September Average Humidity in Coimbra

This chart illustrates the average monthly humidity levels in Coimbra, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec87%81%78%79%78%71%63%64%71%79%86%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Coimbra

In September, Coimbra, Portugal experiences a UV Index of 8, categorized as very high, which means sun exposure can pose risks considerably higher than in the earlier months. As summer transitions to autumn, this index reflects a slight decrease from the peak seen in June but remains notable enough to necessitate caution. With a burn time of only 15 minutes, it’s essential to take protective measures when enjoying outdoor activities. The trend shows that while the risk begins to decrease after August, September still requires vigilance against harmful UV radiation, reinforcing the need for sun safety practices. For more information on UV levels and safety measures, visit Coimbra UV Index.

Maximum UV Index Levels in Coimbra for September

The chart shows the monthly maximum UV Index (UVI) for Coimbra in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec34689111098642
Data source: Coimbra September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Coimbra

As September rolls in, Coimbra, Portugal, basks in a delightful average of 345 sunshine hours—a beautiful transition from the sun-drenched summer months. Following the peak brightness of July, with its impressive 425 hours, the city retains a warm ambiance before the gentle decline into autumn. While September experiences fewer sunshine hours than August's 395, it still offers a bright, pleasant atmosphere that invites exploration of Coimbra's rich history and vibrant culture. This gradual shift in daylight not only signifies the changing seasons but also highlights September as a perfect blend of late summer warmth and early autumn charm, enticing visitors to experience the city's unique allure.

Monthly Sunshine Duration in Coimbra: September Highlighted

The September sunshine duration represents the total number of hours Coimbra experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec169h216h291h344h407h408h425h395h345h306h215h192h
Data source: Coimbra September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Coimbra During September

In Coimbra, Portugal, the likelihood of sunny weather fluctuates throughout the year, with September boasting a 46% chance of sunshine. This positions it just shy of a peak summer experience, reflecting a gradual decline from the soaring 67% in August and the steady 61% in July. As the warmer months transition to autumn, the sunniest days give way to cooler and wetter conditions, as evidenced by the higher chances of precipitation in the subsequent months. Interestingly, despite September's diminished chances compared to its summer predecessors, it still offers more than a fair share of pleasant days, maintaining relatively high optimism for outdoor activities.

Percentage of Sunny Days in September in Coimbra

The chart illustrates the percentage of sunny days in Coimbra throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Coimbra experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec48%20%57%37%48%58%61%67%46%50%68%38%
Data source: Coimbra September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Coimbra in September

As the summer gradually gives way to autumn, September in Coimbra, Portugal, sees a moderate 12 hours of daylight, marking a gentle transition from the longer days of summer. Following a peak of 14 hours in both June and July, daylight begins to wane slightly, echoing a familiar pattern as the year progresses. This reduction continues into October, when daylight dips to 11 hours, and further declines to 9 hours by November, suggesting that the vibrant days of summer are now behind. The shift serves as a reminder of nature's cyclical rhythm, inviting locals and visitors alike to embrace the changing seasons and enjoy the picturesque landscapes that accompany shorter days.

Average Daylight Hours in Coimbra for September

The chart illustrates the variation in daylight duration in Coimbra throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 39m10h 40m11h 58m13h 17m14h 24m14h 58m14h 40m13h 40m12h 24m11h 5m9h 56m9h 20m
Data source: Coimbra daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Coimbra

As September approaches in Coimbra, Portugal, the winds begin to mellow, averaging a gentle 2.6 m/s (6 mph). This slight dip follows the summer months, where the wind speed peaks at 3.3 m/s (7 mph) in July and fluctuates slightly in August before gradually settling down as autumn sets in. Compared to earlier months, September’s breeze offers a refreshing yet soft caress, inviting leisurely strolls along the banks of the Mondego. While the winds may be lighter this month, the transition heralds the arrival of vibrant fall hues, making Coimbra an idyllic setting for those looking to enjoy the calm beauty of early autumn.

Average September Wind Speed in Coimbra

The chart displays monthly wind speed patterns in Coimbra, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.33.72.82.43.13.03.32.72.6 m/s2.62.73.6
Data source: Coimbra September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Coimbra Compares to Other Months

The weather in Coimbra 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 Coimbra and find detailed weather information for every month.

September and January showcase contrasting weather patterns. In September, temperatures range from a mild 9°C (49°F) at night to a scorching high of 37°C (98°F), with an average of 20°C (69°F). The month experiences relatively low precipitation at 36 mm (1.4 in) over just 4 days, and humidity sits at a comfortable 71%. In stark contrast, January presents a much cooler climate, with temperatures dropping to a chilling minimum of -3°C (27°F) and an average of 9°C (48°F), peaking at only 20°C (69°F). Precipitation is heavier during this month, totaling 63 mm (2.5 in) across 7 days, and the humidity rises to a damp 87%. For further details on January weather specifics, check out Coimbra weather in January.

September and February present distinctly different weather patterns. In September, temperatures are warmer, with a minimum of 9°C (49°F) and a maximum reaching up to 37°C (98°F), averaging around 20°C (69°F). The month experiences relatively low precipitation of 36 mm (1.4 in) over just 4 days, accompanied by a humidity level of 71%. In contrast, February sees much cooler temperatures, with a minimum of -1°C (31°F) and a maximum of 23°C (73°F), averaging 11°C (53°F). The precipitation significantly increases to 88 mm (3.5 in) over 9 days, and humidity rises to 81%. For detailed information, visit Coimbra weather in February.

When comparing the weather in September and March, it's clear that each month has its unique characteristics. September tends to be warmer, with average temperatures around 20°C (69°F) and highs reaching up to 37°C (98°F), while March is noticeably cooler, with average temperatures of 12°C (55°F) and a maximum of 27°C (81°F). Precipitation also varies significantly; September experiences only 36 mm (1.4 in) over about four days, whereas March has a much wetter climate, with 117 mm (4.6 in) of rain over approximately eleven days. Additionally, March shows a slightly higher humidity level at 78%, compared to September's 71%. For those interested in more details, check out Coimbra weather in March.

In September, the weather tends to be warmer, with temperatures ranging from a minimum of 9°C (49°F) to a maximum of 37°C (98°F), and an average around 20°C (69°F). The month sees relatively low precipitation, accumulating only 36 mm (1.4 in) over about 4 days, contributing to a moderate humidity level of 71%. In contrast, April is significantly cooler, with temperatures ranging from a minimum of 4°C (39°F) to a maximum of 28°C (84°F) and an average of 14°C (58°F). It experiences much higher rainfall, totaling 120 mm (4.7 in) spread across 13 days, accompanied by slightly higher humidity at 79%. For more details on April weather specifically in Coimbra, you can visit Coimbra weather in April.

In comparing the weather of September and May, September generally offers warmer temperatures, with an average of 20°C (69°F) compared to May's average of 17°C (63°F). The maximum temperature in September can reach as high as 37°C (98°F), while May peaks at 33°C (92°F). However, May tends to experience more rainfall, with 56 mm (2.2 in) of precipitation over about 8 days, compared to September's 36 mm (1.4 in) over just 4 days. Additionally, May has slightly higher humidity levels at 78%, contrasted with September's 71%. For a detailed look at May's weather, check out Coimbra weather in May.

In comparing the weather of September and June, we can observe that both months experience similar temperature ranges, with September having a slightly higher average maximum temperature of 37°C (98°F) compared to June's maximum of 36°C (98°F). Both months have a similar average temperature, with September averaging 20°C (69°F) and June averaging 19°C (66°F). However, September sees a bit more precipitation, totaling 36 mm (1.4 in) over 4 days, while June has slightly less precipitation at 31 mm (1.2 in) spread across 8 days. Interestingly, humidity remains consistent at 71% in both months. Overall, while both months are warm, September tends to be slightly drier and hotter than June. For more details on June weather, check out Coimbra weather in June.

September and July in Coimbra exhibit similar maximum temperatures, both reaching highs of around 37°C (98°F). However, July tends to be slightly warmer overall, with an average temperature of 21°C (70°F) compared to September's 20°C (69°F). In terms of humidity, September is more humid at 71%, while July enjoys a lower humidity of 63%. Precipitation patterns also differ, with September experiencing more rainfall (36 mm over 4 days) than July, which sees only 8 mm over 2 days. For a detailed look at July's weather, you can check Coimbra weather in July.

In comparing the weather of September and August, we observe a slight decline in average temperatures, with September experiencing a minimum of 9°C (49°F) and an average of 20°C (69°F), while August has a minimum of 11°C (52°F) and an average of 21°C (70°F). August typically sees slightly warmer maximum temperatures, reaching up to 39°C (103°F) compared to September's 37°C (98°F). Precipitation levels differ as well, with September receiving a total of 36 mm (1.4 in) of rain over 4 days, whereas August is much drier, recording only 9 mm (0.3 in) over just 1 day. Additionally, humidity is higher in September at 71%, compared to August's 64%. For more detailed information on August weather, you can visit Coimbra weather in August.

September generally sees warmer temperatures compared to October, with average highs reaching up to 37°C (98°F) and a comfortable average of 20°C (69°F). However, it also experiences less precipitation, with only 36 mm (1.4 in) falling over just 4 days. In contrast, October brings cooler conditions, with temperatures averaging 17°C (63°F) and maximums around 35°C (96°F). This month is characterized by increased rainfall, totaling 91 mm (3.6 in) over 8 days, and higher humidity levels at 79%. For more specific weather details, check out Coimbra weather in October.

September typically exhibits a warmer climate compared to November, with average temperatures around 20°C (69°F) and maximums soaring up to 37°C (98°F). In contrast, November sees a significant drop in temperature, with averages plummeting to 13°C (55°F) and a maximum of only 25°C (77°F). Additionally, September is relatively drier, experiencing just 36 mm (1.4 in) of precipitation over 4 days, whereas November is much wetter, receiving 126 mm (5.0 in) over 13 days. The humidity also rises noticeably in November, reaching 86%, compared to September's 71%. For more detailed insights, check out Coimbra weather in November.

September and December present markedly different weather patterns. In September, temperatures range from a mild 9°C (49°F) at night to a scorching maximum of 37°C (98°F) during the day, with an average of 20°C (69°F). The month sees relatively low precipitation at 36 mm (1.4 in) over just four days, accompanied by a moderate humidity level of 71%. In contrast, December brings much cooler temperatures, with a minimum plummeting to -2°C (28°F) and an average of 11°C (52°F), topping out at a mild 19°C (67°F). This winter month also witnesses significantly increased rainfall at 112 mm (4.4 in) across 12 days, and the humidity rises to 87%. To learn more about what to expect, check out Coimbra weather in December.

Compare Coimbra's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Coimbra

In September, Coimbra embraces the gentle transition from the warmth of summer to the cooler embrace of autumn, offering a delightful average temperature of 20°C (69°F). Unlike the intense heat of peak summer, where temperatures can soar to a sweltering 37°C (98°F), September’s climate is more moderate, making it an inviting time for exploration. Although a few rain showers may occur, bringing 36 mm of precipitation over just a handful of days, the overall humidity remains around 71%, lending a pleasant freshness to the air. This month is perfect for outdoor activities with the added bonus of fewer tourists. To learn more about the weather throughout the year, check out Coimbra Climate.