Month by month
| Month | Afternoon | Sea | Rain | Verdict |
|---|---|---|---|---|
| January | 7.4 °C | 8.9 °C | 20 days | Unfavourable season |
| February | 8 °C | 8.3 °C | 19 days | Unfavourable season |
| March | 9.3 °C | 8.5 °C | 19 days | Unfavourable season |
| April | 11.6 °C | 9.7 °C | 16 days | Unfavourable season |
| May | 14.7 °C | 11.7 °C | 16 days | Possible, with trade-offs |
| June | 16.7 °C | 13.9 °C | 19 days | Unfavourable season |
| July | 17.2 °C | 15.2 °C | 22 days | Unfavourable season |
| August | 17.3 °C | 15.7 °C | 23 days | Unfavourable season |
| September | 15.7 °C | 15 °C | 19 days | Unfavourable season |
| October | 12.8 °C | 13.4 °C | 19 days | Unfavourable season |
| November | 9.5 °C | 11.7 °C | 19 days | Unfavourable season |
| December | 8.2 °C | 10.1 °C | 21 days | Unfavourable season |
Nearby in September
Before you go
Three things to check once you have picked your dates.
Entry
No visa needed. No passport is legally required under the Common Travel Area, but some airlines and ferry operators require a valid passport as ID.
For a British passport, per the UK Foreign Office on 4 September 2026. Rules change: check before booking.
Safety
No specific restrictions
Usual precautions apply.
Official advice updated 4 September 2026
Health
Vaccines · hepatitis B if you are not already vaccinated; hepatitis A depending on activities and areas visited. Routine vaccines up to date (measles in particular).
Yellow fever · No yellow fever locally, vaccine not recommended. No entry requirement.
Malaria · None.
Per the CDC (page reviewed 25 August 2026); see a travel clinic a few weeks before departure.
Beau Fixe is not a safety or health authority. These notes summarise dated public texts and link to their source: France Diplomatie (Licence Ouverte 2.0), Foreign, Commonwealth & Development Office (gov.uk, Open Government Licence v3.0), Centers for Disease Control and Prevention (Source: CDC). Only the competent authorities are authoritative.
FAQ
Can you swim in Sligo in September?
The sea averages 15°C in September — too cold for most swimmers.
How hot is Sligo in September?
Expect 15.7°C in the afternoon and 10.2°C at night, averaged over the last 10 years.
Does it rain a lot in Sligo in September?
Around 19 days with rain (≥ 1 mm) in the month — 63% of days.