September Weather in Riga, Latvia

Last updated: August 21, 2025

September in Riga, Latvia is characterized by a delightful blend of mild temperatures and refreshing autumnal charm. The maximum temperature can reach up to 26°C (79°F), while the average hovers around a comfortable 14°C (58°F). As the month progresses, cooler nights can bring temperatures as low as 4°C (40°F). With a total precipitation of 91 mm (3.6 in) over approximately 14 days, expect occasional rain showers that contribute to the lush greenery of the city. The air is notably humid at 87%, adding to the crisp, invigorating atmosphere of this vibrant capital as it transitions into the fall season.

September Temperature in Riga

As summer transitions into autumn, September in Riga brings a delightful change in temperatures. With minimums around 4°C (40°F) and average highs reaching up to 26°C (79°F), the warmth of late summer lingers, offering a comfortable embrace before the chill of winter sets in. This month sees an average temperature of 14°C (58°F), providing a perfect backdrop for enjoying the city's lush parks and historical sites. As the days gradually shorten, the crispness in the air hints at the approaching autumn, making September an ideal time for both locals and visitors to savor Riga’s vibrant outdoor life while still relishing the last rays of summer.

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

The chart illustrates September temperature patterns in Riga, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Riga, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec313035435263666457494133
Data source: Temperature data for Riga 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 Riga

September marks a pivotal transition in Riga's weather, with precipitation reaching 91 mm (3.6 in), reflecting the onset of autumn. This month not only showcases increased rainfall but also sees the highest number of precipitation days of the year at 14 days, indicating a shift towards wetter conditions. Following the summer's peak, where July and August boast substantial precipitation, September's rainfall prepares the city for the cooler, wetter months ahead. As nature shifts gears, these trends suggest an evolving landscape, setting the tone for October's even greater precipitation of 92 mm (3.6 in). Overall, September stands out as a bridge between summer's warmth and the crispness of fall, illustrated by its significant rainfall and increased wet days.

September Precipitation Trends in Riga

The chart displays monthly precipitation patterns in Riga, 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. In Riga, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec483950405358848692926959
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Riga

In September, Riga, Latvia, experiences a noticeable shift in humidity as it transitions from the warmth of summer to the cooler autumn months. With an average humidity of 87%, this month marks a return to higher moisture levels after the relative reprieve of May and June, which saw more moderate figures of 72% and 76%, respectively. As the city begins to prepare for the crisper days ahead, the humidity in September reflects the lingering warmth of summer while gradually aligning with the wetter patterns characteristic of October and beyond, where levels climb back to 91%. The gentle ebb and flow of humidity throughout the year paints a vivid picture of Riga's maritime climate, reminding us how closely intertwined the seasons are with atmospheric conditions.

September Average Humidity in Riga

This chart illustrates the average monthly humidity levels in Riga, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Riga is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec93%91%90%87%72%76%76%80%87%91%92%93%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Riga

In September, Riga experiences a moderate UV Index of 4, reflecting a slight decline from the peak summer months but still warranting caution for sun exposure. With a recommended burn time of 30 minutes, this month marks a transition from the high UV levels of July and August, where values reached 7. As autumn approaches, outdoor enthusiasts can enjoy comfortable conditions, but it’s wise to remain vigilant against UV rays when spending extended time outside. For more detailed insights into sun safety, visit Riga UV Index.

Maximum UV Index Levels in Riga for September

The chart shows the monthly maximum UV Index (UVI) for Riga 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. In September, the maximum UV index in Riga typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec123567764211
Data source: Riga 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 Riga

As September unfolds in Riga, Latvia, the city basks in a delightful 311 hours of sunshine, a warm embrace that bids farewell to summer. This month marks a gentle decline from the sun-drenched heights of June and July, which boasted over 460 hours each, but remains significantly brighter than the gloomy winter months that follow. The trend reveals a gradual decrease in sunshine, with daylight hours dropping from the vibrant 444 hours of May to the crisp October's 232 hours. Yet, as autumn arrives, September’s sunshine still invites locals and visitors alike to enjoy the last glimpses of warmth before the shorter days settle in, making it an ideal time to explore Riga's charming streets and picturesque parks.

Monthly Sunshine Duration in Riga: September Highlighted

The September sunshine duration represents the total number of hours Riga 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.
JanFebMarAprMayJunJulAugSepOctNovDec81h169h269h356h444h463h460h394h311h232h124h79h
Data source: Riga September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Riga During September

In September, Riga, Latvia experiences a 29% chance of sunny weather, reflecting a trend of diminishing sunlight as summer gradually transitions to autumn. This modest probability aligns with the previous month, August, where the chances of bright days similarly stood at 29%. Interestingly, September maintains a pattern typical of early fall, with the likelihood of sun dipping from the peak of 60% in June to a notable low by mid-autumn. As autumn approaches, one can expect intermittent sunny spells interspersed with the beginnings of cooler weather, making this month a transitional period in Riga's climate.

Percentage of Sunny Days in September in Riga

The chart illustrates the percentage of sunny days in Riga 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 Riga experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec7%23%33%39%35%60%50%29%29%36%20%19%
Data source: Riga September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Riga in September

As September rolls into Riga, Latvia, the transition to autumn becomes evident not just in the changing leaves but also in the daylight hours. After enjoying up to 17 hours of daylight in the blissful summer months of June and July, September marks a gentle yet noticeable decline, offering around 12 hours of daylight. This shift signals the onset of shorter days, following the vibrant golden hues of August with its 15 hours of sunlight. As the month progresses, residents and visitors alike can savor the softer light of early autumn, a natural reminder of the impending seasonal change, while still relishing the warmth of lingering daylight.

Average Daylight Hours in Riga for September

The chart illustrates the variation in daylight duration in Riga throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec7h 30m9h 29m11h 52m14h 19m16h 30m17h 43m17h 4m15h 4m12h 42m10h 17m8h 4m6h 50m
Data source: Riga daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Riga

As September unfolds in Riga, Latvia, the average wind speed picks up a notch to 5.1 m/s (11 mph), matching the breezy vibe of the previous spring months. This gentle increase brings a refreshing atmosphere that contrasts with the calmness of the summer, inviting locals and visitors alike to enjoy the city's vibrant parks and waterfronts. The winds start to gather strength as autumn approaches, paving the way for October’s gustier conditions, where speeds rise to 5.7 m/s (13 mph). This trend illustrates a gradual transition from the warm summer breezes to the invigorating fall winds that characterize Latvia's enchanting landscapes.

Average September Wind Speed in Riga

The chart displays monthly wind speed patterns in Riga, 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.
JanFebMarAprMayJunJulAugSepOctNovDec4.94.75.15.04.53.43.94.85.1 m/s5.75.55.3
Data source: Riga September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Riga Compares to Other Months

Weather in Riga varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Riga, focusing on differences in temperature, rainfall, humidity, and UV levels.

September and January present a stark contrast in weather conditions. In September, temperatures range from a minimum of 4°C (40°F) to a pleasant maximum of 26°C (79°F), with an average of 14°C (58°F). The month sees around 91 mm (3.6 in) of precipitation over 14 days, accompanied by relatively high humidity at 87%. In contrast, January is much colder, with temperatures plummeting to a minimum of -19°C (-1°F) and peaking at just 8°C (47°F), averaging -1°C (31°F). Precipitation is less frequent, totaling 48 mm (1.9 in) over 12 days, yet humidity remains high at 93%. For more detailed insights, check out Riga weather in January.

September and February present contrasting weather experiences. In September, temperatures range from a mild 4°C (40°F) at night to a warm 26°C (79°F) during the day, with an average of 14°C (58°F). The month experiences 91 mm (3.6 in) of precipitation over 14 days, accompanied by high humidity at 87%. In stark contrast, February is characterized by much colder conditions, with nighttime lows plummeting to -17°C (1°F) and daytime highs averaging only -1°C (30°F), peaking at 11°C (52°F). The winter month sees significantly less precipitation at 39 mm (1.5 in) across 9 days, but humidity remains high at 91%. For a deeper look at the weather conditions, you can check Riga weather in February.

September in Riga offers a much warmer climate compared to March, with temperatures ranging from a minimum of 4°C (40°F) to a pleasant maximum of 26°C (79°F). The average temperature sits comfortably at 14°C (58°F), making it a transition into autumn where precipitation is relatively high at 91 mm (3.6 in) over about 14 days and humidity levels are around 87%. In contrast, March presents a starkly different picture; it is significantly colder, with temperatures dropping as low as -18°C (0°F) and an average temperature of only 1°C (35°F). The maximum temperature reaches just 12°C (54°F), and while it sees less precipitation at 50 mm (2.0 in) over 12 days, the humidity remains high at 90%. To explore more about March weather, you can check Riga weather in March.

September and April showcase quite distinct weather patterns. In September, temperatures range from a chilly 4°C (40°F) to a warm 26°C (79°F), with an average of 14°C (58°F). The month experiences 91 mm (3.6 in) of precipitation spread over 14 days, creating a humid atmosphere with a consistent humidity level of 87%. In contrast, April is cooler, featuring temperatures from a low of -5°C (23°F) to a maximum of 22°C (71°F), with an average of 6°C (43°F). This month sees less precipitation, totaling 40 mm (1.6 in) over 9 days, while also maintaining the same humidity level of 87%. For a more detailed look at April weather in Riga, you can check out Riga weather in April.

September and May exhibit contrasting weather patterns, despite sharing similar maximum temperatures of 26°C (79°F). In September, temperatures range from a minimum of 4°C (40°F) to an average of 14°C (58°F), often accompanied by higher humidity levels at 87% and increased precipitation of 91 mm (3.6 in) over 14 days. In contrast, May experiences slightly cooler conditions with a minimum of 1°C (33°F) and an average of 11°C (52°F), along with lower precipitation of 53 mm (2.1 in) spread over 10 days and a more comfortable humidity level of 72%. For those interested in exploring more about May weather, visit Riga weather in May.

September and June present quite different weather patterns. In September, the temperatures range from a cooler minimum of 4°C (40°F) to a maximum of 26°C (79°F), with an average temperature of 14°C (58°F). The month is characterized by higher humidity at 87% and more days of precipitation, totaling 91 mm (3.6 in) over 14 days. In contrast, June features warmer weather, with minimum temperatures of 7°C (45°F) and maximums reaching 31°C (88°F), culminating in an average of 17°C (64°F). June also sees less rainfall, with only 58 mm (2.3 in) over 10 days and lower humidity at 76%. For a more detailed look at weather conditions specifically in June, you can check out Riga weather in June.

When comparing the weather in September to that of July, we notice a distinct shift in temperature and humidity. September sees a cooler range with minimum temperatures dropping to 4°C (40°F) and average highs reaching 26°C (79°F), while July boasts milder nights around 11°C (52°F) and warmer averages peaking at 31°C (88°F). Additionally, September experiences greater humidity levels at 87%, contributing to a more damp atmosphere compared to July’s 76%. Precipitation is slightly higher in September, with 91 mm (3.6 in) recorded over 14 days, compared to July's 84 mm (3.3 in) over 13 days. For more details on July weather, visit Riga weather in July.

In comparison to August, September experiences cooler temperatures with a minimum of 4°C (40°F) and an average of 14°C (58°F), while August boasts a warmer minimum of 9°C (48°F) and an average of 18°C (65°F). The maximum temperatures in September can reach up to 26°C (79°F), contrasting with August's peak of 30°C (86°F). Precipitation is similar between the two months, with September receiving 91 mm (3.6 in) over 14 days and August having slightly less at 86 mm (3.4 in) across 13 days. Additionally, September's humidity is higher at 87%, compared to August's 80%. For more details on August's weather, check out Riga weather in August.

September tends to be warmer than October, with average temperatures ranging from a minimum of 4°C (40°F) to a maximum of 26°C (79°F). In contrast, October experiences cooler temperatures, with a minimum of -1°C (31°F) and a maximum of 19°C (66°F), resulting in an overall average of 9°C (49°F). Both months have a similar amount of precipitation, with September receiving 91 mm (3.6 in) over 14 days and October slightly higher at 92 mm (3.6 in) over 16 days. The humidity also increases in October, reaching 91% compared to September's 87%. For a detailed look at October weather patterns, check out Riga weather in October.

In September, the weather is generally milder with average temperatures ranging from a minimum of 4°C (40°F) to a maximum of 26°C (79°F), creating a comfortable atmosphere for outdoor activities. With an average precipitation of 91 mm (3.6 in) over 14 days and a humidity level of 87%, September can feel a bit damp, but it often experiences pleasant sunny intervals. In contrast, November brings a sharp drop in temperatures, with averages between -7°C (20°F) and 14°C (57°F), reflecting the onset of winter. Although November sees less precipitation at 69 mm (2.7 in) over 15 days, the humidity rises slightly to 92%, making the air feel colder. For more details on November weather, visit Riga weather in November.

In September, the weather is generally mild, with temperatures ranging from a minimum of 4°C (40°F) to a maximum of 26°C (79°F), averaging around 14°C (58°F). The month sees about 91 mm (3.6 in) of precipitation over 14 days, with humidity levels at 87%. In contrast, December brings much colder temperatures, with a minimum of -13°C (9°F) and a maximum of 10°C (50°F), averaging just 1°C (33°F). While precipitation decreases to 59 mm (2.3 in), it occurs over 15 days, and humidity rises slightly to 93%. For more detailed insights on this month, visit Riga weather in December.

Compare Riga's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Riga

As September unfolds in Riga, the transition from summer to autumn is unmistakable. Temperatures begin to cool, with highs reaching a pleasant 26°C, yet the average hovers around a mild 14°C, signaling a gentle shift in the season. Rainfall becomes more frequent, with about 14 days of precipitation totaling 91 mm, contributing to the higher humidity of 87%. This month serves as a graceful farewell to the warmth of summer, inviting a refreshing crispness that sets the stage for the vibrant colors of autumn. For more details on what to expect throughout the year, visit Riga Climate.