Grand Cayman in September

In September, Grand Cayman averages 31°C (87°F) during the day and 27°C (81°F) at night, with frequent rain — about 28 days of the month see precipitation (104 mm total).

Off-peak

Conditions are warm and beach-friendly. Expect daily rain or showers, often in heavy bursts.

It's peak hurricane season in Grand Cayman during September. Travel is possible but expect storm risk, possible flight disruption, and generally lower travel insurance coverage.

31°C
Avg high
27°C
Avg low
28
Rain days
104 mm
Rainfall

How September compares to the rest of the year in Grand Cayman

3rd
warmest month of the 12
4th
wettest month of the 12
11%
of yearly rainfall falls in September
12 h 15 min
daylight on the 15th

September is one of the warmest months in Grand Cayman (3rd of 12) and moderately rainy compared to the rest of the year (4th of 12). Daytime temperature runs 1°C above the annual average (29°C). September runs roughly the same as August (31°C) and cools 1°C in October (30°C).

September sunrise & sunset in Grand Cayman

🌅
Sunrise (15th)
6:12 AM
🌇
Sunset (15th)
6:28 PM
Day length
12 h 15 min

Times shown for Grand Cayman local time (America/Cayman), calculated for the 15th of September. They shift by a few minutes day to day across the month.

Photography light in Grand Cayman — September

Golden-hour and blue-hour windows for the 15th of September, in Grand Cayman's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).

🌅 Blue hour (AM)
5:12 AM – 5:52 AM
🌄 Golden hour (AM)
5:52 AM – 6:52 AM
🌇 Golden hour (PM)
5:48 PM – 6:48 PM
🌆 Blue hour (PM)
6:48 PM – 7:28 PM
Milky Way galactic core
Fair
Core only briefly above the horizon — a marginal month even from dark sites near Grand Cayman.

📅 When to book — Grand Cayman in September

Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (Off-peak) and Grand Cayman's popularity.

✈ Flights — lead time
3-6 weeks
Cheapest flights of the year. Last-minute deals are real if you can be flexible. ⚠ Peak hazard season — book flexible-change tickets and travel insurance with weather-disruption coverage.
🏨 Lodging — lead time
2-4 weeks
Last-minute bookings work fine. Some seasonal properties close — call ahead if it's a small boutique or beach resort.

Crowds & pricing — September in Grand Cayman

Off-peak

This is off-peak for Grand Cayman — the lowest prices of the year and the fewest crowds, but with real trade-offs: some restaurants, hotels, and beach businesses may close for the season; weather conditions can make outdoor activities unpredictable; and a handful of seasonal sights run reduced hours or close entirely. Great if you prefer a quiet local rhythm and don't mind the climate giving you reasons to choose indoor activities.

Why this tier: peak hazard season (1 active)

Sun & mosquito risk — September in Grand Cayman

☀️ UV Index (noon, 15th)
12.3
Extreme
Stay indoors during midday hours; SPF 50+ even briefly outside, UPF clothing, wide-brim hat, sunglasses essential.
🦟 Mosquito risk
●●●●●
Severe
Severe mosquito season with active disease transmission risk. DEET 30%+, picaridin 20%, long sleeves day and night, treated nets, and check CDC/WHO travel advisories before going.

UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.

Sea temperature in Grand Cayman — September

30.6°C (87°F)
bath-warm
tropical and comfortable for hours

Across the year Grand Cayman's sea swings from 26.9°C (February) to 30.6°C (August) — September sits at 30.6°C.

Grand Cayman in other months

MonthAvg highAvg lowRainfallRain daysSnow days
January 27°C / 81°F 25°C / 76°F 41 mm 24
February 27°C / 81°F 25°C / 76°F 37 mm 23
March 28°C / 82°F 25°C / 76°F 50 mm 24
April 29°C / 84°F 25°C / 78°F 48 mm 24
May 29°C / 85°F 26°C / 78°F 120 mm 29
June 30°C / 86°F 27°C / 80°F 120 mm 26
July 31°C / 87°F 27°C / 81°F 54 mm 29
August 31°C / 88°F 27°C / 81°F 100 mm 28
September 31°C / 87°F 27°C / 81°F 104 mm 28
October 30°C / 85°F 26°C / 80°F 155 mm 28
November 29°C / 83°F 26°C / 78°F 104 mm 26
December 28°C / 82°F 25°C / 78°F 51 mm 23

Other cities with similar September weather

🌍 See the full ranked list of climate twins for Grand Cayman in September →

Frequently asked questions

How hot is Grand Cayman in September?

In September, Grand Cayman averages a high of 31°C (87°F) and a low of 27°C (81°F) — generally hot.

Does it rain a lot in Grand Cayman in September?

September is quite rainy in Grand Cayman, with about 28 rainy days on average.

Is September a good time to visit Grand Cayman?

September is hot but on the rainy side. It suits travelers who are comfortable with hot weather; check the month-by-month ranking to compare it against the rest of the year.

What should I pack for Grand Cayman in September?

Pack lightweight, breathable clothing, sunglasses and sunscreen, plus a compact umbrella or rain jacket. See the full September packing list for Grand Cayman for a complete, climate-based checklist.

Open Grand Cayman on the interactive map

Check the live 10-day forecast and sunrise/sunset.