Letterkenny weather in September 2026

Expect daytime maximum temperatures of 59°F in Letterkenny, Ireland in September based on long-term weather averages. There are 3 hours of sunshine per day on average with 22 days with some rainfall and typically 4.7 inches of rainfall in the month.

  • 59°F maximum daytime temperature in September in Letterkenny59
    59°F max day temperature
  • 3 hours of sunshine per day
  • 22 days with some rainfall in September in Letterkenny22
    22 days with some rainfall
  • 46°F minimum night-time temperature in September in Letterkenny46
    46°F min night temperature
  • 13 hours of daylight per day in September in Letterkenny13
    13 hours of daylight per day
  • No heat & humidity in September in Letterkenny0
    No heat & humidity
  • 4.7 inches monthly rainfall in September in Letterkenny4.7
    4.7 inches of monthly rainfall
  • UV (maximum) index 3 (Moderate) in September in Letterkenny3
    3 (Moderate) UV index

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The September weather guide for Ireland (Letterkenny) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C)  |  Imperial (°F)

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More about Ireland

How warm is it in Letterkenny in September?

Daytime temperatures usually reach 63°F in Letterkenny in September, falling to 50°F at night.

How sunny is it in Letterkenny in September?

There are normally 4 hours of bright sunshine each day in Letterkenny in September - that's 33% of daylight hours.

How warm is the sea around Letterkenny in September?

The average sea temperature around Letterkenny in September is 57°F.

Does it rain in Letterkenny in September?

There are usually 15 days with some rain in Letterkenny in September and the average monthly rainfall is 2.5 inches.

Letterkenny September sunrise & sunset times

Browse the sunrise and sunset times for Letterkenny in September 2026. Select a month to view Letterkenny sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Tuesday, 1st September 2026 05:37 19:23
Tuesday, 15th September 2026 06:03 18:48
Wednesday, 30th September 2026 06:31 18:09

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