September Weather in Bilbao, Spain

Last updated: February 6, 2025

September in Bilbao, Spain offers a warm transition from summer to autumn, with maximum temperatures reaching up to 30°C (86°F) and an average of 18°C (65°F). As the month progresses, temperatures dip to a comfortable minimum of 10°C (50°F) at night. While the sunshine is pleasant, rainfall is not uncommon, contributing a total of 81 mm (3.2 in) over about 12 days, leading to a humidity level of 77%. This dynamic weather makes September an ideal time to enjoy Bilbao's vibrant culture while experiencing the changing seasons.

September Temperature in Bilbao

In September, Bilbao greets visitors with a delightful transition from summer warmth to the crispness of autumn. The temperatures range from a pleasant 10°C (50°F) at night to an inviting 30°C (86°F) during the day, offering a comfortable average of 18°C (65°F). This month marks a subtle cooldown from the peak summer heat, yet still provides ample sunshine for outdoor exploration. As summer fades, travelers can enjoy the vibrant city without the sweltering temperatures, making September an ideal time for enjoying Bilbao's stunning architecture and rich culture.

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

The chart illustrates September temperature patterns in Bilbao, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec465051545863666764595350
Data source: Temperature data for Bilbao 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 Bilbao

September in Bilbao marks a subtle transition as summer wanes and autumn approaches. With 81 mm (3.2 in) of precipitation spread over 12 days, the month maintains a moderate dampness characteristic of the Basque Country. This is a slight uptick from the drier months of July and August, which saw minimal rain, yet remains significantly lower than the impending rainier months of October and November. As the days shorten and temperatures cool, September’s rainfall provides a refreshing prelude to the more intense precipitation that follows, highlighting the region's shift into the wetter season.

September Precipitation Trends in Bilbao

The chart displays monthly precipitation patterns in Bilbao, 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.
JanFebMarAprMayJunJulAugSepOctNovDec117103989282104656281105158154
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Bilbao

As summer transitions into autumn, September brings a noticeable dip in humidity levels in Bilbao, Spain, settling at around 77%. This marks a shift from the peak summer months, where humidity soared to 87% in July. While humidity remains relatively high throughout the year, with winter months hovering between 83% and 85%, September's figures suggest a refreshing change as the city prepares for cooler temperatures. This slight decrease not only enhances comfort for residents and visitors alike but also serves as a sign of the shifting seasons, inviting the vibrant landscape of Bilbao to embrace the autumnal palette.

September Average Humidity in Bilbao

This chart illustrates the average monthly humidity levels in Bilbao, 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.
JanFebMarAprMayJunJulAugSepOctNovDec85%83%82%81%81%83%87%82%77%80%83%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Bilbao

As summer fades into fall, September in Bilbao shows a notable transition in UV exposure, with a UV Index of 7, categorized as high. This reflects a slight decline from the intense very high levels of August and July, yet individuals should still exercise caution, as the burn time remains at 25 minutes. This month bridges the gap between summer sun and the cooler autumn months, emphasizing the importance of sun protection even as temperatures begin to drop. For more detailed insights on UV trends throughout the year, visit Bilbao UV Index.

Maximum UV Index Levels in Bilbao for September

The chart shows the monthly maximum UV Index (UVI) for Bilbao 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.
JanFebMarAprMayJunJulAugSepOctNovDec24679101097532
Data source: Bilbao 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 Bilbao

September in Bilbao, Spain, welcomes the warm embrace of golden sunshine, with 332 hours illuminating the city. This month, along with April, marks a turning point as the days start to shorten, yet still enjoy substantial daylight. As summer fades, temperatures remain pleasant, contrasting sharply with the winter months that follow, where sunshine dips significantly to 293 hours in October and further decreases throughout the colder season. The steady decline in sunlight from the summer peak of 400 hours in July emphasizes the vibrancy of September, making it an ideal time to explore the city's rich culture and stunning landscapes before the darker days arrive.

Monthly Sunshine Duration in Bilbao: September Highlighted

The September sunshine duration represents the total number of hours Bilbao 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.
JanFebMarAprMayJunJulAugSepOctNovDec172h241h313h332h375h376h400h381h332h293h232h226h
Data source: Bilbao September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Bilbao During September

In Bilbao, Spain, September typically signals a gentle transition towards autumn, characterized by a 27% chance of sunny weather. This month witnesses a slight dip in sunshine compared to the peak summer months of July and August, both boasting a 37% chance of clear skies. After a robust spring, where March shines at 40%, and with varying odds in the earlier months, September's sunlit days are fewer yet still offer a pleasant respite before the cooler months set in. As the year progresses, the likelihood of sunny days fluctuates, with October resuming a somewhat brighter 36%, hinting at the resilience of clear weather as summer fades. Thus, while September offers some sunshine, it's merely a prelude to the richer hues of fall.

Percentage of Sunny Days in September in Bilbao

The chart illustrates the percentage of sunny days in Bilbao 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 Bilbao experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec23%22%40%34%28%32%37%37%27%36%18%39%
Data source: Bilbao September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Bilbao in September

As September rolls into Bilbao, the city enjoys a delightful 12 hours of daylight, marking a gentle transition towards the shorter days of autumn. This month showcases a gradual decline from the summer highs of 15 hours in June and 14 hours in July, where the sun lights up the streets late into the evening. Following the vibrant days of August, which also basked in 13 hours of daylight, September offers a more tempered light. This month's daylight serves as a reminder of the impending shift, yet it still provides ample opportunity for outdoor activities and picturesque strolls as the vibrant hues of fall begin to emerge. With daylight hours steadily tapering off as October approaches, September stands as a bridge between the warm, sun-soaked days of summer and the crisp, cozy embrace of autumn.

Average Daylight Hours in Bilbao for September

The chart illustrates the variation in daylight duration in Bilbao throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 21m10h 30m11h 57m13h 26m14h 41m15h 19m14h 59m13h 52m12h 27m10h 58m9h 40m9h
Data source: Bilbao daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Bilbao

As September arrives in Bilbao, Spain, the breeze shows a subtle revival from the summer lull, with an average wind speed of 2.6 m/s (6 mph). This slight uptick from the preceding months signals a gentle shift in the atmosphere, paving the way for autumn's arrival. Over the warmer months, the city experiences a gradual decline in wind speed, reaching a low of 2.4 m/s (5 mph) in August. However, with the onset of September, the winds begin to whisper of change, hinting at the brisker conditions that follow in October and November, where speeds climb once again. This changing rhythm sets the stage for a lively transition, as the air grows crisper and the scenic landscapes of Bilbao prepare for their breathtaking autumnal hues.

Average September Wind Speed in Bilbao

The chart displays monthly wind speed patterns in Bilbao, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.84.33.43.22.82.82.62.42.6 m/s2.93.84.6
Data source: Bilbao September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Bilbao Compares to Other Months

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

September and January present quite contrasting weather patterns. In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 30°C (86°F) with an average of 18°C (65°F), making it a warm month with notable summer remnants. This period also experiences relatively high humidity at 77% and moderate precipitation, with 12 rainy days totaling 81 mm (3.2 in). In stark contrast, January's climate is notably cooler, with temperatures dipping as low as -1°C (30°F) and averaging around 8°C (46°F). While the maximum reaches 19°C (66°F), this month tends to be wetter, with 117 mm (4.6 in) of precipitation spread over 13 days and a higher humidity level at 85%. For further details on January weather, you can check Bilbao weather in January.

September and February offer contrasting weather experiences. In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 30°C (86°F), creating a warm and pleasant atmosphere with an average temperature of 18°C (65°F). However, the month brings about significant humidity at 77% and 81 mm (3.2 in) of rainfall over approximately 12 days. In contrast, February features much cooler temperatures, with a minimum of -2°C (30°F) and maximum of 22°C (72°F); the average temperature drops to 10°C (50°F). Despite being chillier, February sees slightly higher precipitation, at 103 mm (4.0 in) spread over 13 days, accompanied by a humidity level of 83%. For more details on February weather, you can visit Bilbao weather in February.

When comparing the weather in September and March, notable differences emerge. September boasts milder temperatures, with a minimum of 10°C (50°F) and an average of 18°C (65°F), reaching highs of up to 30°C (86°F). In contrast, March experiences cooler conditions, with temperatures dipping as low as -1°C (30°F) and averaging around 10°C (51°F). Precipitation levels are also higher in March, totaling 98 mm (3.9 in) over 17 days, compared to September's 81 mm (3.2 in) over 12 days. Both months exhibit high humidity, with March slightly higher at 82% versus September's 77%. For more detailed information, you can check the Bilbao weather in March.

September and April present notably different weather patterns. In September, the temperatures typically range from a minimum of 10°C (50°F) to a maximum of 30°C (86°F), creating a warm average of 18°C (65°F). This month sees about 81 mm (3.2 in) of precipitation over approximately 12 days, with a humidity level of 77%. In contrast, April experiences cooler temperatures, with a minimum of 1°C (34°F), an average of 12°C (54°F), and a maximum of 23°C (74°F). It also has slightly higher rainfall, totaling 92 mm (3.6 in) over around 15 days, accompanied by a humidity of 81%. For more detailed information, check Bilbao weather in April.

In comparing the weather of September and May, September generally experiences warmer temperatures, with a minimum of 10°C (50°F) and an average of 18°C (65°F), compared to May's minimum of 5°C (41°F) and average of 14°C (58°F). While both months have similar levels of precipitation at around 81-82 mm (3.2 in), May sees rain on more days, averaging 15 days compared to September's 12 days. Humidity levels are also quite comparable, with September at 77% and May slightly higher at 81%. For more specific details on the weather trends, you can check Bilbao weather in May.

When comparing the weather in September and June, we see some notable differences. September tends to have slightly higher average temperatures, with a minimum of 10°C (50°F) and a maximum of 30°C (86°F), while June starts off just a notch cooler with a minimum of 9°C (48°F) and can reach up to 32°C (89°F). Precipitation levels are also distinct; September experiences 81 mm (3.2 in) of rain over 12 days, whereas June sees more rain, totaling 103 mm (4.1 in) over 14 days. Additionally, humidity levels are relatively high in both months, with September registering 77% and June slightly higher at 83%. For more detailed information, you can check the Bilbao weather in June.

In comparing the weather of September and July, September typically experiences a slightly wider temperature range, with minimum temperatures averaging around 10°C (50°F) and maximums reaching up to 30°C (86°F). In contrast, July has a slightly higher average temperature, ranging from a minimum of 11°C (53°F) to a maximum of 33°C (91°F). Precipitation levels in September are notably higher at 81 mm (3.2 in) over 12 days, compared to July's 65 mm (2.6 in) over the same number of days. Humidity also tends to be lower in September at 77%, while July peaks at 87%. To explore more about weather specifics in July, visit Bilbao weather in July.

In comparing the weather between August and September, we see a notable shift as summer transitions into autumn. August typically boasts warmer temperatures, with a minimum of 12°C (54°F), an average of 20°C (67°F), and a maximum reaching 33°C (93°F). In contrast, September experiences cooler temperatures, with a minimum of 10°C (50°F) and a maximum of 30°C (86°F), reflecting the gradual drop in warmth as summer gives way to fall.

Precipitation is slightly higher in September, totaling 81 mm (3.2 in) over 12 days, compared to 62 mm (2.5 in) also over 12 days in August. Additionally, while humidity levels remain comparable, September sees a humidity level of 77%, slightly lower than August's 82%. For more detailed information about August weather, you can check this link: Bilbao weather in August.

September weather is characterized by warmer temperatures, with averages around 18°C (65°F) and maximums reaching 30°C (86°F). In contrast, October sees a notable drop in temperatures, averaging 15°C (59°F) and peaking at 27°C (81°F). While September experiences around 81 mm (3.2 in) of precipitation over 12 days, October is slightly wetter, with 105 mm (4.1 in) of rain spread across 13 days. Additionally, humidity remains fairly high in both months, increasing slightly from September's 77% to October's 80%. For more detailed information, you can visit Bilbao weather in October.

September and November exhibit notable contrasts in weather. September experiences milder temperatures, ranging from a minimum of 10°C (50°F) to a maximum of 30°C (86°F), with an average of 18°C (65°F). In contrast, November's temperatures are considerably cooler, with a minimum of 4°C (39°F), an average of 11°C (53°F), and a maximum of 22°C (72°F). Additionally, November sees significantly higher precipitation, totaling 158 mm (6.2 in) across 18 days of rain, compared to September's 81 mm (3.2 in) over 12 days. Humidity levels also increase slightly, with November sitting at 83% compared to September's 77%. For more details, check out Bilbao weather in November.

In September, the weather is quite warm with average temperatures around 18°C (65°F) and maximums reaching up to 30°C (86°F), making it a pleasant time to enjoy outdoor activities. However, the month does see a fair amount of rainfall, totaling 81 mm (3.2 in) across about 12 days, with humidity levels at 77%.

In contrast, December brings a notable drop in temperatures, averaging around 10°C (50°F) with maximums of only 19°C (66°F). Precipitation increases significantly to 154 mm (6.1 in) over 17 days, and humidity rises to 85%, contributing to a much cooler and wetter atmosphere. For those interested in specific weather details, you can find more at Bilbao weather in December.

Compare Bilbao's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Bilbao

As summer gently transitions into autumn, September in Bilbao offers a unique blend of warmth and occasional rainfall, making it distinctly different from the hotter, drier summer months. With average temperatures hovering around 18°C (65°F) and a peak of 30°C (86°F), you'll enjoy pleasant days ideal for exploring the city. However, the 77% humidity and about 81 mm (3.2 in) of precipitation over 12 days remind you that the changing seasons bring unpredictable weather. This month strikes a balance between lingering summer heat and the cool embrace of fall, perfect for experiencing Bilbao's vibrant culture and scenery. For more insights into how September compares to the rest of the year, check out the details at Bilbao Climate.