Updated 2 Nov 2026 · recomputed nightly
Is September 2027 a good month to visit Kos?
Busy — the typical September day in Kos is busier than 71% 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 Kos's own year — not a headcount.
September 2027 is peak-season Kos: hot and dry, around 28°C / 83°F, and Busy every day.
No — not if you want Kos to yourself. Every one of September's 30 days in our window is Busy or Packed, and the typical day is Busy. It is crowded throughout. Expect around 28 °C by day, with rain on about 2 days. The crowd comes with the school holidays in Germany and the Netherlands. Cruise ships call on 2 of the 30 days. No week of September is meaningfully quieter — the typical day is Busy throughout; pick by day instead. For similar weather with fewer people, come in October or May. The crush is at the Asklepion at coach hours; the quiet is at the coastal bike path. The calmest day is Sunday 12 September, the busiest Thursday 2 September.
In short, worth it for the peak buzz, if you can take the crowds.
Among the 12 months we forecast for Kos, September ranks 4th for crowd pressure. Its heaviest day is Thu 2 Sep, busier than 83% of the year; its lightest is Sun 12 Sep at 71%.
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 →
Plan around the heat — around 28°C by day.
Refilling costs nothing and saves the walk to find a shop.
See water bottles →
The one thing you wear all day, every day of the trip.
See walking shoes →
How busy is Kos in September?
Every day is Busy — the crowd level barely shifts.
Ships call on 2 of 30 days, a typical call day carrying at least 3,012 guests — real, but a secondary part of the crowd here; the season moves the needle more.
The month barely moves — every day lands between 71% and 83% of the year. Daylight runs about 12 hours.
Either side of it, October is far calmer.
The lightest days are the 12th, 13th and 14th. Still busy — but the easiest of the month — 17 days share that level, so there is room to choose.
Wed 01 Sep Busy busier than 74% of days here · Germany school holidays
Record Kos on Wed 1 Sep 2027 is forecast Busy. Why: school holidays in Germany and the Netherlands. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-01 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 02 Sep Busy busier than 83% of days here · ⚓1 · Germany school holidays
- Costa Pacifica — guest capacity 3,012 07:00–17:00
Record Kos on Thu 2 Sep 2027 is forecast Busy. Why: school holidays in Germany and the Netherlands. 1 cruise ship scheduled, at least 3,012 guests at double occupancy; ships in port 07:00–17:00. Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-02 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Fri 03 Sep Busy busier than 74% of days here · Germany school holidays
Record Kos on Fri 3 Sep 2027 is forecast Busy. Why: school holidays in Germany and the Netherlands. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-03 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sat 04 Sep Busy busier than 74% of days here · Germany school holidays
Record Kos on Sat 4 Sep 2027 is forecast Busy. Why: school holidays in Germany and the Netherlands. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-04 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sun 05 Sep Busy busier than 74% of days here · Germany school holidays
Record Kos on Sun 5 Sep 2027 is forecast Busy. Why: school holidays in Germany and the Netherlands. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-05 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Mon 06 Sep Busy busier than 73% of days here · Germany school holidays
Record Kos on Mon 6 Sep 2027 is forecast Busy. Why: school holidays in Germany. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-06 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Tue 07 Sep Busy busier than 73% of days here · Germany school holidays
Record Kos on Tue 7 Sep 2027 is forecast Busy. Why: school holidays in Germany. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-07 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Wed 08 Sep Busy busier than 73% of days here · Germany school holidays
Record Kos on Wed 8 Sep 2027 is forecast Busy. Why: school holidays in Germany. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-08 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 09 Sep Busy busier than 73% of days here · Germany school holidays
Record Kos on Thu 9 Sep 2027 is forecast Busy. Why: school holidays in Germany. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-09 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Fri 10 Sep Busy busier than 73% of days here · Germany school holidays
Record Kos on Fri 10 Sep 2027 is forecast Busy. Why: school holidays in Germany. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-10 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sat 11 Sep Busy busier than 73% of days here · Germany school holidays
Record Kos on Sat 11 Sep 2027 is forecast Busy. Why: school holidays in Germany. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-11 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sun 12 Sep Busy busier than 71% of days here · Germany school holidays
Record Kos on Sun 12 Sep 2027 is forecast Busy. Why: school holidays in Germany. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-12 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Mon 13 Sep Busy busier than 71% of days here · Germany school holidays
Record Kos on Mon 13 Sep 2027 is forecast Busy. Why: school holidays in Germany. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-13 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Tue 14 Sep Busy busier than 71% of days here
Record Kos on Tue 14 Sep 2027 is forecast Busy. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-14 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Wed 15 Sep Busy busier than 71% of days here
Record Kos on Wed 15 Sep 2027 is forecast Busy. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-15 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 16 Sep Busy busier than 71% of days here
Record Kos on Thu 16 Sep 2027 is forecast Busy. The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-16 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Fri 17 Sep Busy busier than 71% of days here
Record Kos on Fri 17 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-17 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sat 18 Sep Busy busier than 71% of days here
Record Kos on Sat 18 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-18 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sun 19 Sep Busy busier than 71% of days here
Record Kos on Sun 19 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-19 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Mon 20 Sep Busy busier than 74% of days here · Germany public holiday
Record Kos on Mon 20 Sep 2027 is forecast Busy. Why: Germany public holiday. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-20 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Tue 21 Sep Busy busier than 71% of days here
Record Kos on Tue 21 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-21 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Wed 22 Sep Busy busier than 71% of days here
Record Kos on Wed 22 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-22 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 23 Sep Busy busier than 71% of days here
Record Kos on Thu 23 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-23 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Fri 24 Sep Busy busier than 71% of days here
Record Kos on Fri 24 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-24 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sat 25 Sep Busy busier than 71% of days here
Record Kos on Sat 25 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-25 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Sun 26 Sep Busy busier than 71% of days here
Record Kos on Sun 26 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-26 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Mon 27 Sep Busy busier than 82% of days here · ⚓1
- Oosterdam — guest capacity 1,916
Record Kos on Mon 27 Sep 2027 is forecast Busy. 1 cruise ship scheduled, at least 1,916 guests at double occupancy. Nearest calmer day: Fri 1 Oct (Lively). Ship-by-ship detail for the day, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-27 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Tue 28 Sep Busy busier than 71% of days here
Record Kos on Tue 28 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-28 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Wed 29 Sep Busy busier than 71% of days here
Record Kos on Wed 29 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-29 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Thu 30 Sep Busy busier than 71% of days here
Record Kos on Thu 30 Sep 2027 is forecast Busy. Nearest calmer day: Fri 1 Oct (Lively). The day in full, the year at a glance, and what's worth booking ahead: https://avoid-crowds.com/kos/#d-2027-09-30 (Avoid-Crowds, as of 2 Nov 2026; recomputed nightly.)
Which week of September is quietest in Kos?
No week of September is meaningfully quieter — the typical day is Busy throughout; pick by day instead.
Can't move the dates? How to avoid the worst crowds
- 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 Kos
Real heat — around 28°C / 83°F by day, so pace the afternoons and carry water, with rain on only about 2 days.
Book beds and the big-ticket sights well ahead, and start your days by eight — in a month this full, the early hours are the only uncrowded ones.
More about Kos in September
Based on: Greece's public holidays · school vacations across Germany and the Netherlands · 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.
