September Weather in Mainz, Germany

Last updated: February 26, 2025

September in Mainz, Germany, offers a delightful transition from summer to autumn, showcasing a maximum temperature of 33°C (91°F) and an average of 16°C (61°F). Despite the rise in warmth, cooler evenings can dip to a minimum of 3°C (37°F), inviting a cozy atmosphere. Rainfall is moderate, with 45 mm (1.8 in) spread over 7 days, contributing to the lush, vibrant landscapes characteristic of this time of year. Coupled with a high humidity of 85%, these conditions create a refreshing environment perfect for exploring the historical charm and scenic beauty of Mainz.

September Temperature in Mainz

In Mainz, Germany, September marks a delightful transition from the sweltering summer months to the crispness of fall. With temperatures ranging from a minimum of 3°C (37°F) to a pleasant average of 16°C (61°F), daytime highs can soar to a balmy 33°C (91°F), offering a perfect opportunity for outdoor activities and enjoying the stunning autumn foliage. As summer's warmth lingers, residents and visitors alike can relish in comfortable weather, making this month an inviting time to explore the city's rich history and vibrant culture. However, as the month progresses, the gradual dip in temperatures hints at the approaching chill, reminding everyone that autumn is just around the corner.

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

The chart illustrates September temperature patterns in Mainz, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec363943505767686860524239
Data source: Temperature data for Mainz generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Mainz

In September, Mainz experiences a noticeable drop in precipitation, with only 45 mm (1.8 in) of rain falling over approximately 7 days. This marks a decline from the wetter summer months, where rain totals averaged above 60 mm. The transition from the lush greenery of summer to the drier autumn is evident, as September typically serves as a bridge to the cooler, crisper days of fall. With fewer rainy days compared to the previous months, locals and visitors alike can enjoy more sunshine as they savor the changing leaves and prepare for the upcoming shifts in weather patterns.

September Precipitation Trends in Mainz

The chart displays monthly precipitation patterns in Mainz, 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.
JanFebMarAprMayJunJulAugSepOctNovDec565263347176646045544794
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Mainz

As summer transitions into autumn, September in Mainz, Germany, witnesses a slight uptick in humidity, reaching 85%. This marks a small rise from the summer months when humidity hovered around 83-84%. The lingering warmth of late summer is gradually tempered by the cooler autumn air, leading to a more comfortable yet noticeable moisture in the atmosphere. Compared to earlier months, such as May at 79%, September’s humidity indicates a shift back towards the higher levels characteristic of the winter months, which peak at 91% in January and December. This subtle increase not only enriches the air but also sets the stage for the seasonal changes that lie ahead.

September Average Humidity in Mainz

This chart illustrates the average monthly humidity levels in Mainz, 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.
JanFebMarAprMayJunJulAugSepOctNovDec91%89%87%83%79%82%83%84%86%88%89%91%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Mainz

In September, the UV Index in Mainz, Germany, stands at a moderate level of 5, with a burn time of 30 minutes. This marks a shift from the peak summer months, where values soared to 8, indicating very high exposure. While September still calls for sun protection, especially during midday, the decline from the intense summer UV levels makes it slightly more manageable. This month serves as a gentle reminder that as we transition into autumn, UV exposure remains significant, encouraging outdoor enthusiasts to stay informed. For more detailed insights, check the Mainz UV Index.

Maximum UV Index Levels in Mainz for September

The chart shows the monthly maximum UV Index (UVI) for Mainz 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.
JanFebMarAprMayJunJulAugSepOctNovDec234588875421
Data source: Mainz 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 Mainz

As summer fades into autumn, September in Mainz, Germany, offers a delightful transition with an impressive 318 hours of sunshine. Following the peak of summer sun in July, which boasts 411 hours, September retains a vibrant glow, significantly more luminous than the winter months ahead. This month serves as a bridge, balancing the lingering warmth of summer with the crispness of fall. While sunshine levels begin to wane compared to peak summer, they remain markedly brighter than the darker days of October and November. The abundant September sun not only enriches the landscapes but also invites both locals and visitors to savor the city's beauty before the colder months set in, making it a perfect time for outdoor exploration and enjoyment.

Monthly Sunshine Duration in Mainz: September Highlighted

The September sunshine duration represents the total number of hours Mainz 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.
JanFebMarAprMayJunJulAugSepOctNovDec108h201h264h344h382h391h411h383h318h244h168h122h
Data source: Mainz September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Mainz During September

As summer transitions to autumn, September in Mainz, Germany offers a notable increase in sunny weather, with the chances of sunshine peaking at 41%. This elevation compared to the preceding months suggests a promising farewell to the sun-drenched days of August, where the likelihood dipped slightly to 30%. Following a trend of fluctuating sunlight, September stands out, providing a delightful window for outdoor activities before the cooler months set in. However, as temperatures begin to drop, the subsequent months illustrate a clear decline, highlighting September as a sweet spot for enjoying the lingering warmth and brightness of summer.

Percentage of Sunny Days in September in Mainz

The chart illustrates the percentage of sunny days in Mainz 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 Mainz experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec12%33%45%45%31%33%34%30%41%28%17%14%
Data source: Mainz September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Mainz in September

As September rolls into Mainz, Germany, daylight begins to wane, offering approximately 12 hours of light each day. This marks a gradual transition from the long, sunlit days of summer, where June peaks at an impressive 16 hours. The trend from late spring and into summer shows an upward trajectory in daylight duration, reaching its zenith in June and tapering off steadily until September. After this month, the days continue to shorten, descending into the dimmer months of autumn and winter. The shift from an average of 15 hours in May to 14 in August highlights a noticeable decline, preparing residents for the cozy, candle-lit atmosphere that defines the later months of the year.

Average Daylight Hours in Mainz for September

The chart illustrates the variation in daylight duration in Mainz throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 37m10h 5m11h 55m13h 47m15h 25m16h 15m15h 49m14h 21m12h 33m10h 41m9h 1m8h 9m
Data source: Mainz daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Mainz

As summer transitions into autumn, September in Mainz experiences a notable dip in wind speed, averaging just 2.1 m/s (5 mph). This decrease reflects a broader trend in monthly averages, where the warmest months typically boast higher winds, peaking in May at 3.4 m/s (8 mph). Following the lively breezes of summer, September’s gentle winds seem to usher in the contemplative shift of fall, hinting at the calming atmospheric changes that define the upcoming months. As the vibrant activity of summer wanes, the soft sigh of the September wind invites tranquil moments, reminiscent of the slowing pace of life.

Average September Wind Speed in Mainz

The chart displays monthly wind speed patterns in Mainz, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.32.93.02.73.42.22.42.62.1 m/s2.72.42.7
Data source: Mainz September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Mainz Compares to Other Months

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

September and January present strikingly different weather conditions. In September, temperatures can vary widely, with lows of 3°C (37°F) and highs reaching up to 33°C (91°F), creating a warm average of 16°C (61°F). The month experiences about 45 mm (1.8 inches) of precipitation over roughly 7 days, accompanied by relatively high humidity at 85%. In contrast, January brings much colder temperatures, where minimums plummet to -9°C (15°F) and averages only reach 2°C (37°F), with a maximum of 13°C (55°F). Precipitation increases slightly to 56 mm (2.2 inches) over about 11 days, and humidity also rises to 91%. For more details about the weather in January, check out Mainz weather in January.

September and February present contrasting weather patterns. In September, temperatures range from a minimum of 3°C (37°F) to a maximum of 33°C (91°F), with an average of 16°C (61°F). This month typically sees 45 mm (1.8 in) of precipitation over about 7 days, accompanied by a relatively high humidity level of 85%. In contrast, February features much colder weather, with temperatures dipping to a minimum of -11°C (13°F), peaking at a maximum of 18°C (65°F), and averaging around 4°C (39°F). Precipitation increases slightly to 52 mm (2.0 in) over approximately 11 days, while humidity rises to 89%. For more detailed information about February's weather, check out Mainz weather in February.

When comparing the weather in September and March, notable differences emerge in temperature and precipitation. September experiences a broader temperature range, with minimums around 3°C (37°F) and maximums reaching up to 33°C (91°F), leading to an average of 16°C (61°F). In contrast, March has colder conditions, with minimum temperatures plunging to -11°C (13°F) and a milder maximum of 22°C (72°F), resulting in a lower average of 6°C (44°F). Precipitation is also a factor, as September sees about 45 mm (1.8 in) over 7 days, while March has higher precipitation at 63 mm (2.5 in) spread over 13 days. Both months have similar humidity levels, hovering around 85% in September and slightly higher at 87% in March. For a detailed look at March weather specifics, visit Mainz weather in March.

When comparing the weather in September and April, notable differences emerge. September typically boasts a wider temperature range, with minimums around 3°C (37°F) and maximums reaching up to 33°C (91°F), resulting in an average of 16°C (61°F). April, on the other hand, starts off chillier, with minimum temperatures averaging -4°C (26°F) and a maximum of 27°C (80°F), leading to an average temperature of 10°C (50°F). Precipitation is slightly less in April, totaling 34 mm (1.3 in), compared to September's 45 mm (1.8 in), although both months see an average of 7 days of rain. Humidity levels are comparable, with September at 85% and April slightly lower at 83%. For more detailed information on April weather, visit Mainz weather in April.

In September, temperatures range from a cool 3°C (37°F) to a warm 33°C (91°F), averaging around 16°C (61°F), while May sees slightly lower temperatures, with a minimum of 0°C (33°F), an average of 14°C (57°F), and a maximum of 32°C (90°F). Despite similar high temperatures, September experiences higher humidity at 85% compared to May's 79%. Precipitation is also more frequent in May, with rain occurring on 12 days and totaling 71 mm (2.8 in), whereas September has 7 wet days and 45 mm (1.8 in) of rainfall. For more details on May weather, you can check Mainz weather in May.

In comparing the weather between September and June, we notice some distinct differences. September typically experiences a wider temperature range, with minimums around 3°C (37°F) and maximums reaching up to 33°C (91°F), while June's temperatures are generally milder, with minimums of 7°C (45°F) and maximums peaking at 36°C (97°F). Precipitation in June is higher, averaging 76 mm (3.0 in) over 11 days compared to September's 45 mm (1.8 in) over 7 days, although September has slightly higher humidity at 85% compared to June's 82%. For more detailed information, you can check Mainz weather in June.

In comparing the weather of September and July, we observe notable differences in temperature and precipitation. September experiences a broader range of temperatures, with a minimum of 3°C (37°F) and a maximum of 33°C (91°F), while July has milder temperatures, ranging from 8°C (47°F) to a high of 39°C (103°F). Precipitation is also more frequent in July, occurring over 11 days with a total of 64 mm (2.5 in), compared to September's 7 days of rain amounting to 45 mm (1.8 in). Humidity levels are similar in both months, hovering around 83% in July and 85% in September, suggesting a consistently damp atmosphere. For more detailed information, you can check out Mainz weather in July.

In comparing the weather of September and August, September experiences a wider temperature range with a minimum of 3°C (37°F) and a maximum of 33°C (91°F), while August tends to be warmer with a minimum of 7°C (44°F) and a maximum of 36°C (96°F). The average temperature in September is lower at 16°C (61°F) compared to August's 20°C (68°F). Precipitation in September is slightly less at 45 mm (1.8 in) over 7 days, whereas August sees more rain with 60 mm (2.3 in) over 12 days. Humidity levels remain similar, with September at 85% and August at 84%. For more detailed insights, check Mainz weather in August.

September typically features a wider temperature range, with minimums around 3°C (37°F) and maximums reaching up to 33°C (91°F), resulting in an average temperature of 16°C (61°F). The month experiences about 45 mm (1.8 in) of precipitation over 7 days, with humidity levels around 85%. In contrast, October sees cooler temperatures, with minimums dropping to 0°C (32°F) and an average of 11°C (52°F); peaks are generally lower too, at around 26°C (79°F). The month records slightly higher precipitation at 53 mm (2.1 in) over 11 days, along with a slight increase in humidity to 88%. For more detailed information on October weather, check out Mainz weather in October.

September typically features warmer temperatures, with averages around 16°C (61°F) and maximums reaching 33°C (91°F). In contrast, November sees cooler conditions, where average temperatures drop to 6°C (43°F) and maximums peak at 21°C (70°F). Both months experience similar precipitation levels, with September recording 45 mm (1.8 in) over 7 days and November slightly higher at 47 mm (1.9 in) but over 11 days. Additionally, humidity levels rise in November, averaging 89% compared to September's 85%. For a more detailed look at the weather in November, you can refer to Mainz weather in November.

In September, the weather is notably warm, with temperatures ranging from a mild 3°C (37°F) to a maximum of 33°C (91°F) and an average of 16°C (61°F). The month experiences about 45 mm (1.8 in) of precipitation over approximately 7 days, accompanied by a relatively high humidity level of 85%. In contrast, December brings much cooler conditions, with temperatures dipping to a minimum of -6°C (21°F) and averaging only 4°C (39°F). The maximum temperature in December is significantly lower at 14°C (58°F). Moreover, this month sees increased precipitation, totaling 94 mm (3.7 in) across about 17 days, along with even higher humidity levels of 91%. For more information about the December weather, visit Mainz weather in December.

Compare Mainz's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Mainz

As September unfolds in Mainz, it brings a delightful shift in weather, offering a blend of warmth and crispness that sets it apart from the height of summer. With maximum temperatures occasionally reaching up to 33°C (91°F), this month still retains the lingering warmth of summer, but the average temperature settles comfortably at a more manageable 16°C (61°F). Unlike the sweltering July and August, September invites cooler evenings, with lows dipping to 3°C (37°F), making it ideal for cozy gatherings. Although the month experiences about 45 mm (1.8 in) of rainfall spread over 7 days, the humidity remains relatively high at 85%, adding a touch of tropical feel to the early autumn days. This unique blend creates a perfect opportunity to enjoy the outdoors while witnessing the gradual changing of leaves and the onset of a colorful fall. For those interested in a deeper dive into weather patterns, check out Mainz Climate.