nomadseason

September Weather in Londonderry, United States

Last updated: June 24, 2025

In September, the average temperature in Londonderry, United States hovers around 16°C (61°F). While you might experience minimum chills of -2°C (28°F), the sun can also bring warmth with highs reaching up to 30°C (87°F). Expect about 95 mm (3.7 in) of precipitation spread over 9 days, contributing to an average humidity of 72%. Stay prepared for a mix of experiences this month!

September Temperature in Londonderry

In September in Londonderry, the average temperature is 16°C (61°F), with a maximum reaching 30°C (87°F) and a minimum dipping as low as -2°C (28°F). When traveling to Londonderry during this month, be prepared for a wide range of temperatures and pack accordingly.

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

The chart illustrates September temperature patterns in Londonderry, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Londonderry, September typically has an average temperature of 16°C (61°F), with highs reaching up to 30°C (87°F) and lows dropping to around -2°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec212430435564696760493425
Data source: Temperature data for Londonderry 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 Londonderry

In Londonderry in September, the precipitation amount is 95 mm (3.7 in) over the course of 9 days.

September Precipitation Trends in Londonderry

The chart displays monthly precipitation patterns in Londonderry, 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 Londonderry, September typically receives around 95 mm (3.7 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec78917813110311416312095157107105
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Londonderry

In Londonderry in September humidity is 72%. With an average temperature of 16°C (61°F), this humidity feels like a damp blanket wrapping around you, making every step feel heavier and requiring extra effort while traveling.

September Average Humidity in Londonderry

This chart illustrates the average monthly humidity levels in Londonderry, 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 Londonderry is approximately 72%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%88%86%84%76%72%67%64%72%81%87%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Londonderry

In Londonderry in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Londonderry.

Maximum UV Index Levels in Londonderry for September

The chart shows the monthly maximum UV Index (UVI) for Londonderry 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 Londonderry typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34681010997632
Data source: Londonderry 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.

How September Weather in Londonderry Compares to Other Months

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

This table compares monthly weather conditions in Londonderry, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (21°F)78 mm (3.1 inches)89%moderate
February Weather-5°C (24°F)91 mm (3.6 inches)88%moderate
March Weather-1°C (31°F)78 mm (3.1 inches)86%high
April Weather6°C (43°F)131 mm (5.2 inches)84%very high
May Weather13°C (55°F)103 mm (4.0 inches)76%very high
June Weather18°C (64°F)114 mm (4.5 inches)72%very high
July Weather21°C (69°F)163 mm (6.4 inches)66%very high
August Weather20°C (67°F)120 mm (4.7 inches)64%very high
September Weather16°C (61°F)95 mm (3.7 inches)72%high
October Weather9°C (49°F)157 mm (6.2 inches)81%high
November Weather1°C (35°F)107 mm (4.2 inches)87%moderate
December Weather-4°C (26°F)105 mm (4.1 inches)84%low

Compare Londonderry's Climate with Cities Worldwide