Ireland
Dublin in September: weather, sea & travel advice
This month's data profile
Rain shapes the decision
Dublin in September is climatically mixed. The average daily high is around 16 °C, and the sea is about 15 °C. With about 14 rainy days it is wet.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
40/100 · #4
Warmth
#4
Dryness
#2
Sun
#6
Sea warmth
#3
Published best categories: City break
Dublin · SeptemberPhoto: Holger Uwe Schmitt · CC BY-SA 4.0Climate facts
- Average high
- 16 °C
- Average low
- 11 °C
- Sea
- 15 °C
- Rainy days (est.)
- 14 rainy days (est.)
- Sun (est.)
- 4 h/day
- Humidity
- 87 %
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Sea °C | Score |
|---|---|---|---|---|---|---|---|---|---|
| August | 18 | 12 | 16 | 88 | 4.9 | 86 | 3.7 | 15 | 45 |
| September (selected) | 16 | 11 | 14 | 81 | 3.7 | 87 | 4.2 | 15 | 40 |
| October | 13 | 9 | 17 | 101 | 2.2 | 88 | 4.9 | 13 | 26 |
How do the previous and next months compare?
Baseline: September (40/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | Sea Δ | |
|---|---|---|---|---|---|---|---|---|---|
| August | +5 | +1.7 °C | +1.3 °C | +1.9 | +7.4 mm | +1.2 h | -1.2 % | -0.5 m/s | +0.6 °C |
| October | -14 | -2.8 °C | -2 °C | +3.2 | +19.7 mm | -1.5 h | +1.1 % | +0.7 m/s | -1.2 °C |
All twelve months in context
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Useful next decisions
Frequently asked questions
How warm is Dublin in September?
The average daily high is around 16 °C, with an average daily low of about 11 °C.
Can you swim in Dublin in September?
The sea is about 15 °C (cold).
Does it rain a lot in Dublin in September?
The curated estimate is about 14 rainy days per month, not a directly measured long-term average. Total precipitation averages around 81 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit Dublin?
No month in Dublin reaches the threshold for a clear recommendation in the climate score; the month comparison above shows the differences.