Best time to visit Con Dao: dry months, rough seas, turtles

July and August are worth the rain only for turtles. November to February is big-wave season, and every tropical storm that passed within 150 km of the island in 35 seasons came in November or December.

Con Dao month by month: our call

Rain, rain days and mean wind are the Côn Đảo station averages in Vietnam's building climate code, QCVN 02:2022/BXD. Sea temperature is from weather2travel, and Climates to Travel agrees within half a degree. Boat, flight and turtle notes are linked in the sections below. For sights and transport, see our Con Dao destination page.

Highs only run from 27.9°C (82°F) in January to 31.9°C (89°F) in May, so temperature never decides the month. March, at 11.2 mm, is also the island's entry in our driest month list, and our note on rain days against millimetres explains why we show both.

Why the wind decides your trip

The northeast monsoon, gió chướng, sets in during November and peaks from mid-December into January (Phu Quoc Express). The fast-boat operator flags October to February as the months "when the sea often has big waves" (our translation of its Vietnamese page). Its boats run until the port authority bans sailing, and then you get a free date change or a full refund (Phu Quoc Express, Ben Dam port). The harbour authority usually says by 7 p.m. the day before whether the port opens, sometimes not until 7 a.m. on the day (Con Dao Dive Center). Our rule from November to February is one spare day between the boat back and any flight home.

Flying is no way round it. The airport takes ATR-72 turboprops on a short runway with no night flights (VietnamSpot transport guide), and one travel blog, VietnamSpot, puts thunderstorm delays from June to October at two to four hours; we found no airline figure to check it against. Our airports by destination guide has the routes.

Pick your beach by the season. In the northeast monsoon the waves land on the east side, along Con Son bay, so stay or swim on the calmer west side; Dam Trau is our pick, and Phu Quoc Express's first choice too. In June and July the sides swap: VietnamSpot has the west coast churning while the east stays calm.

Where other guides get Con Dao wrong

We checked eight competing guides against the station. Four claims don't hold:

• November is not dry. Revitrip gives November to April "10-60mm monthly, 2-8 rainy days", and LocalVietnam and north-vietnam.com also start the dry season in November. The station logs 174.9 mm on 12.3 rain days. One November in ten gets more than 324.7 mm, nearly an average October, and the wettest day in its table, 276.4 mm, fell in a November.
• November to February is not calm. Revitrip promises calm seas, although its own wind line gives "25-35mph northeastern winds Dec-Jan", and north-vietnam.com calls those months the best time "for optimal comfort and calm seas". They are the island's windiest, from 3.2 m/s in November to 4.1 in December.
• The storm season is not May to October, as Revitrip lists it. By our count in the NOAA archive for 1991 to 2025 (winds of at least 34 knots), seven tropical storms passed within 150 km of the island, three in November and four in December, none from June to October (IBTrACS). Climates to Travel gets this right with a southern window of 15 October to 20 December; our typhoon season guide runs the same count for other places.
• January is not 74 mm, as weather2travel shows from UK and Dutch climate datasets. The island's own station logs 12.5 mm.

The November question is a real one: a traveller on r/VietNam asked on 12 October 2026 whether Con Dao was "worth a risk in November" or whether to take Phu Quoc instead. Our answer is that it is a risk, so go only if your dates can slide, and compare the rest of the country in our Vietnam in November guide.

Turtles and diving

For turtles, book July or August. Nesting runs from April to September (Côn Đảo National Park), but July and August trips see nesting turtles about 98% of the time (Con Dao Dive Center). Other sources stretch or shrink that window, from April to November down to June to September, but every one of them includes July and August. The park's volunteer season at Bay Canh is over for 2026: on 18 October the park reported its last volunteers leaving Bay Canh as the first northeast wind arrived (park news).

We'd book the park's own overnight trip, CDP 009, listed at 2,150,000 to 5,100,000 dong on 7 November 2026 (park trip page). Its price list, from 2017 but still posted, caps a group at six people and takes 50% off if no turtle lays. The dive centre's tour starts at 3,200,000 dong, with up to eight guests a night.

Divers should come from March to May; April and May are the calmest. The island's tourism portal calls March to June the best diving. From October to February diving is limited. Con Dao Dive Center cancels boat trips when the harbour shuts, goes out on other days only when conditions are safe, and may still offer shore and night dives to experienced divers, with visibility of 5 to 15 m. The wet months are set against the rest of the south in our rainy season guide.

This winter: a normal November, a drier December

The national forecasting centre's outlook of 15 October 2026 gives a very strong El Niño a 96% chance of lasting from November to January (NCHMF outlook). Its rain forecast covers the whole southern region, where it files Côn Đảo's station, so these are regional figures, not a forecast for the island:

El Niño won't dry out November, then, so go that month only if your dates can slide.

It also expects fewer storms than usual. Less rain doesn't mean less wind, though. If you can only travel this winter, we'd pick February over December or January: the outlook has little rain in all three, but February's mean wind is 3.3 m/s against 4.1 and 4.0. December elsewhere is in our Vietnam in December guide.

How we checked this

We read the Côn Đảo rows of QCVN 02:2022/BXD and the NCHMF outlook on 5 November 2026, re-read the operator, park, dive centre and competitor pages on 7 November, and counted storms in IBTrACS.

What we could not confirm

The code doesn't say which years its station tables cover. We found no dated port authority notice for a past sailing ban, and the park's trip page carries no date, so check turtle prices with the park before you book.

References

• QCVN 02:2022/BXD, Vietnam building code climate data, tables A.1 to A.33 and B.4
• NCHMF seasonal outlook, 15 October 2026
• NOAA IBTrACS storm archive, 1991 to 2025
• Phu Quoc Express: Ben Dam port and sailing bans
• Côn Đảo National Park: turtle nesting season
• Côn Đảo National Park: eco-tourism price list