Leinster weather in September
September is one of the best months to visit Leinster: highs of 16°C (61°F) and about 76 mm (3.0 in) of rain on average. Nights average 11°C (52°F) and cloud cover 74% (NASA POWER, 2001–2025 averages). The sea averages 15°C (60°F). It is the 5th driest month of the year and the 4th warmest. Compared with August, it is cooler and drier; October brings highs of 13°C (56°F) and 102 mm (4.0 in) of rain.
Figures are long-term averages for Dublin, the largest city in Leinster. See below for other places.
Is September a good time to visit Leinster?
best month Weather score 61/100.
Yes. September is one of the best months for weather in Leinster.
Does it rain a lot in Leinster in September?
Some rain is normal: about 76 mm (3.0 in) falls in an average September. It is the 5th driest month of the year.
How warm is Leinster in September?
Days average 16°C (61°F) and nights 11°C (52°F).
Leinster weather by month
| Month | High | Low | Rain | Cloud | Sea | Weather |
|---|---|---|---|---|---|---|
| January | 8°C (46°F) | 4°C (39°F) | 86 mm | 78% | 7°C (45°F) | least pleasant |
| February | 8°C (46°F) | 4°C (39°F) | 70 mm | 76% | 8°C (46°F) | least pleasant |
| March | 9°C (48°F) | 4°C (39°F) | 70 mm | 74% | 8°C (47°F) | least pleasant |
| April | 11°C (52°F) | 6°C (42°F) | 61 mm | 73% | 11°C (51°F) | fair |
| May | 14°C (57°F) | 8°C (47°F) | 67 mm | 73% | 14°C (58°F) | fair |
| June | 16°C (62°F) | 11°C (51°F) | 76 mm | 76% | 15°C (60°F) | best |
| July | 18°C (64°F) | 12°C (54°F) | 80 mm | 78% | 17°C (62°F) | best |
| August | 18°C (64°F) | 12°C (54°F) | 91 mm | 78% | 17°C (63°F) | best |
| September | 16°C (61°F) | 11°C (52°F) | 76 mm | 74% | 15°C (60°F) | best |
| October | 13°C (56°F) | 9°C (48°F) | 102 mm | 74% | 13°C (56°F) | fair |
| November | 10°C (50°F) | 7°C (44°F) | 106 mm | 73% | 11°C (52°F) | least pleasant |
| December | 8°C (47°F) | 5°C (41°F) | 97 mm | 76% | 9°C (47°F) | least pleasant |
Sources: 2001–2025 monthly averages from NASA POWER (MERRA-2 reanalysis), sea temperature from Open-Meteo Marine. Page updated . How we rate months
Weather across Leinster in September
Weather can differ a lot within Leinster: coasts, hills and mountains each have their own climate.
| Place | High | Low | Rain | Weather |
|---|---|---|---|---|
| Dublin | 16°C (61°F) | 11°C (52°F) | 76 mm | best |
| South Dublin | 16°C (61°F) | 11°C (52°F) | 76 mm | best |
| Tallaght | 16°C (61°F) | 11°C (52°F) | 76 mm | best |
| Drogheda | 16°C (61°F) | 11°C (52°F) | 76 mm | best |
| Dundalk | 16°C (60°F) | 11°C (51°F) | 82 mm | best |
| Swords | 16°C (61°F) | 11°C (52°F) | 76 mm | best |
| Navan | 17°C (62°F) | 9°C (48°F) | 76 mm | best |
| Bray | 16°C (61°F) | 11°C (51°F) | 81 mm | best |
| Dún Laoghaire | 16°C (61°F) | 11°C (52°F) | 76 mm | best |
| Carlow | 16°C (61°F) | 9°C (48°F) | 84 mm | best |
| Portlaoise | 17°C (62°F) | 9°C (48°F) | 81 mm | best |
| Athlone | 17°C (62°F) | 9°C (49°F) | 89 mm | best |