Updated 2 Nov 2026 · recomputed nightly
Is September 2027 a good month to visit Dublin?
Lively — the typical September day in Dublin is busier than 63% of its year.
If you are coming for something that only happens in September, that is the trade. If not, January is quieter.
Calm · Lively · Busy · Packed rank a day against Dublin's own year — not a headcount.
September sits between the seasons in Dublin: mild and wet, around 18°C / 64°F with rain on about 13 days, Lively on 15 of 30 days — 15 days run Busy or Packed.
Mostly yes, if the weather does not put you off. The typical September day in Dublin is Lively, and 15 of the 30 days in our window run Busy or Packed, so most days feel crowded. Expect around 18 °C by day, with rain on about 13 days. The crowd comes with the school holidays in Germany. Cruise ships call on 14 of the 30 days. Irish Champions Festival (Leopardstown day) falls on 11 September. Late September is the month's quietest stretch in Dublin — the typical day at 58%, against 74% in mid September. The crush is at Temple Bar's cobbles at night; the quiet is at the Georgian squares. The calmest day is Thursday 16 September, the busiest Saturday 11 September.
In short, a solid middle-ground pick.
Among the 12 months we forecast for Dublin, September ranks 5th for crowd pressure. Its heaviest day is Sat 11 Sep, busier than 99% of the year; its lightest is Thu 16 Sep at 58%.
Preparing pays off in a month like this: timed-entry tickets and pre-booked tours turn the queue time into sightseeing time. see the options →
Pack for wet first — rain on 13 of 30 days.
A folding one lives in the day bag and weighs nothing.
See umbrellas →
Wet stone is the thing to plan around in a month this wet.
See walking shoes →
How busy is Dublin in September?
The busiest days are the 11th, 13th, 14th and 19th, and 11 more. Away from those, most days sit Lively. The calmest stretch is the 27th–30th.
Ships call on 14 of 30 days, a typical call day carrying at least 1,696 guests between them — real, but a secondary part of the crowd here; the season moves the needle more.
The month is not one thing: its lightest day sits at 58% of the year and its heaviest at 99%, so where you land inside it matters. All four Sundays run Busy or Packed. Daylight runs about 12 hours.
Either side of it, August is busier still and October is far calmer.
The calmest days include the 16th, 17th and 18th — 10 days share that level, so there is room to choose.
Wed 01 Sep Lively busier than 59% of days here · Germany school holidays
Record Dublin on Wed 1 Sep 2027 is forecast Lively. Why: school holidays in Germany. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-01 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 02 Sep Packed busier than 87% of days here · ⚓2 · Germany school holidays
- Norwegian Star — guest capacity 2,348 07:00–19:00
- SeaDream I — guest capacity 112
Record Dublin on Thu 2 Sep 2027 is forecast Packed. 2 cruise ships scheduled, at least 2,460 guests at double occupancy. Why: school holidays in Germany. Nearest calmer day: Wed 1 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-02 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Fri 03 Sep Lively busier than 59% of days here · Germany school holidays
Record Dublin on Fri 3 Sep 2027 is forecast Lively. Why: school holidays in Germany. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-03 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sat 04 Sep Lively busier than 59% of days here · Germany school holidays
Record Dublin on Sat 4 Sep 2027 is forecast Lively. Why: school holidays in Germany. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-04 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sun 05 Sep Busy busier than 66% of days here · ⚓1 · Germany school holidays
- Oceania Sirena — guest capacity 684 07:00–19:00
Record Dublin on Sun 5 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 684 guests at double occupancy; ships in port 07:00–19:00. Why: school holidays in Germany. Nearest calmer day: Sat 4 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-05 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Mon 06 Sep Busy busier than 72% of days here · ⚓1 · Germany school holidays
- Viking Sky — guest capacity 928
Record Dublin on Mon 6 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 928 guests at double occupancy. Why: Germany school holidays; United States public holiday. Nearest calmer day: Sat 4 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-06 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Tue 07 Sep Packed busier than 85% of days here · ⚓1 · Germany school holidays
- Norwegian Star — guest capacity 2,348 07:00–20:00
Record Dublin on Tue 7 Sep 2027 is forecast Packed. 1 cruise ship scheduled, at least 2,348 guests at double occupancy; ships in port 07:00–20:00. Why: school holidays in Germany. Nearest calmer day: Mon 6 Sep (Busy). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-07 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Wed 08 Sep Busy busier than 73% of days here · ⚓1 · Germany school holidays
- Oceania Marina — guest capacity 1,258 07:00–19:00
Record Dublin on Wed 8 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 1,258 guests at double occupancy; ships in port 07:00–19:00. Why: school holidays in Germany. Nearest calmer day: Fri 10 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-08 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 09 Sep Busy busier than 80% of days here · ⚓2 · Germany school holidays
- Oceania Insignia — guest capacity 698 07:00–19:00
- Viking Libra — guest capacity 998
Record Dublin on Thu 9 Sep 2027 is forecast Busy. 2 cruise ships scheduled, at least 1,696 guests at double occupancy. Why: school holidays in Germany. Nearest calmer day: Fri 10 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-09 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Fri 10 Sep Lively busier than 59% of days here · Germany school holidays
Record Dublin on Fri 10 Sep 2027 is forecast Lively. Why: school holidays in Germany. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-10 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sat 11 Sep Packed busier than 99% of days here · ⚓1 · Germany school holidays · Irish Champions Festival (Leopardstown day)
- Viking Astrea — size unknown (uncounted)
Record Dublin on Sat 11 Sep 2027 is forecast Packed. Why: school holidays in Germany; Irish Champions Festival. 1 cruise ship scheduled, sizes unknown. Nearest calmer day: Fri 10 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-11 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sun 12 Sep Busy busier than 66% of days here · ⚓1 · Germany school holidays
- Seven Seas Voyager — guest capacity 706 08:00–17:00
Record Dublin on Sun 12 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 706 guests at double occupancy; ships in port 08:00–17:00. Why: school holidays in Germany. Nearest calmer day: Fri 10 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-12 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Mon 13 Sep Packed busier than 94% of days here · ⚓1 · Germany school holidays
- Majestic Princess — guest capacity 3,560 07:00–19:00
Record Dublin on Mon 13 Sep 2027 is forecast Packed. 1 cruise ship scheduled, at least 3,560 guests at double occupancy; ships in port 07:00–19:00. Why: school holidays in Germany. Nearest calmer day: Sun 12 Sep (Busy). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-13 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Tue 14 Sep Packed busier than 88% of days here · ⚓1
- Nieuw Statendam — guest capacity 2,666
Record Dublin on Tue 14 Sep 2027 is forecast Packed. 1 cruise ship scheduled, at least 2,666 guests at double occupancy. Nearest calmer day: Wed 15 Sep (Busy). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-14 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Wed 15 Sep Busy busier than 82% of days here · ⚓1
- AIDAsol — guest capacity 2,194 10:00–20:00
Record Dublin on Wed 15 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 2,194 guests at double occupancy; ships in port 10:00–20:00. Nearest calmer day: Thu 16 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-15 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 16 Sep Lively busier than 58% of days here
Record Dublin on Thu 16 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-16 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Fri 17 Sep Lively busier than 58% of days here
Record Dublin on Fri 17 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-17 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sat 18 Sep Lively busier than 58% of days here
Record Dublin on Sat 18 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-18 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sun 19 Sep Packed busier than 93% of days here · Irish Life Dublin Half Marathon
Record Dublin on Sun 19 Sep 2027 is forecast Packed. Why: Irish Life Dublin Half Marathon. Nearest calmer day: Sat 18 Sep (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-19 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Mon 20 Sep Lively busier than 60% of days here · Germany public holiday
Record Dublin on Mon 20 Sep 2027 is forecast Lively. Why: Germany public holiday. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-20 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Tue 21 Sep Busy busier than 84% of days here · ⚓1
- Norwegian Star — guest capacity 2,348 07:00–19:00
Record Dublin on Tue 21 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 2,348 guests at double occupancy; ships in port 07:00–19:00. Nearest calmer day: Mon 20 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-21 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Wed 22 Sep Lively busier than 58% of days here
Record Dublin on Wed 22 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-22 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 23 Sep Busy busier than 66% of days here · ⚓1
- Seven Seas Splendor — guest capacity 754 08:00–18:00
Record Dublin on Thu 23 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 754 guests at double occupancy; ships in port 08:00–18:00. Nearest calmer day: Wed 22 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-23 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Fri 24 Sep Lively busier than 58% of days here
Record Dublin on Fri 24 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-24 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sat 25 Sep Lively busier than 58% of days here
Record Dublin on Sat 25 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-25 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sun 26 Sep Busy busier than 71% of days here · ⚓1
- Viking Sky — guest capacity 928
Record Dublin on Sun 26 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 928 guests at double occupancy. Nearest calmer day: Sat 25 Sep (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/dublin/#d-2027-09-26 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Mon 27 Sep Lively busier than 58% of days here
Record Dublin on Mon 27 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-27 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Tue 28 Sep Lively busier than 58% of days here
Record Dublin on Tue 28 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-28 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Wed 29 Sep Lively busier than 58% of days here
Record Dublin on Wed 29 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-29 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 30 Sep Lively busier than 58% of days here
Record Dublin on Thu 30 Sep 2027 is forecast Lively. The day in full, the year at a glance, and how this day compares: https://avoid-crowds.com/dublin/#d-2027-09-30 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Which week of September is quietest in Dublin?
Late September is the month's quietest stretch in Dublin — the typical day at 58%, against 74% in mid September.
Can't move the dates? How to avoid the worst crowds
- Need flexibility? The 27th–30th is the month's calmest stretch — the easiest window to move around in.
- On the busy days, the walk-up queues for the big sights are the biggest time-sink — a timed-entry ticket skips them, which is where a busy month is won or lost.
Travelling on a busy day?
Timed-entry and skip-the-line tickets turn queue time into sightseeing time — sort them before you fly.
September weather in Dublin
Mild — around 18°C / 64°F, with a light jacket for the evenings, with rain on about 13 days, so keep a layer handy.
Worth booking the marquee sights ahead for the busy days, but you can keep the rest of the trip flexible.
More about Dublin in September
Based on: Ireland's public holidays · school vacations across France and Germany · the season pattern from official overnight stays · five years of weather records (2019–2023) · confirmed event dates · the published cruise schedule
Every figure is recomputed nightly from real cruise schedules, public and school holidays, and long-run climate normals. Gaps are shown, not filled.
