Home › Destinations › Thousand Islands
Weather in Thousand Islands
River castles and St. Lawrence splendor
—
Loading live weather...
About Thousand Islands
A remarkable destination worth exploring.
Best months to visit
July, August, September
Things to do in Thousand Islands
Explore
Dine
Culture
Nature
Shopping
Day trips
Weather by month
Click any month for detailed weather information and travel tips.
January
-2C
Cold, with some rainy days.
February
-1C
Cold, with some rainy days.
March
4C
Cold, with some rainy days.
April
11C
Cool, with some rainy days.
May
18C
Mild and comfortable, with some rainy days.
June
23C
Mild and comfortable, with some rainy days.
Recommended
July
26C
Warm and pleasant, with some rainy days.
Recommended
August
25C
Warm and pleasant, with some rainy days.
Recommended
September
22C
Mild and comfortable, with occasional showers.
October
15C
Cool, with some rainy days.
November
7C
Cold, with some rainy days.
December
3C
Cold, with some rainy days.
The Thousand Islands scatter across the St. Lawrence River where it leaves Lake Ontario, a maze of more than a thousand granite islands ranging from bare rocks to private estates topped with turreted mansions like Boldt Castle. Boat tours weave between the islands from towns on both the Canadian and American sides, offering a relaxed mix of river scenery, history and small-town charm.
Best areas to stay in Thousand Islands
Kingston
A historic Ontario city at the islands' western edge, with boat tours, a waterfront and 19th-century limestone architecture.
Gananoque
A small Ontario town that serves as a popular base for Thousand Islands boat cruises.
Alexandria Bay
The main town on the New York side, with cruises departing for Boldt Castle and the surrounding islands.
Boldt Castle
An ornate, unfinished mansion on Heart Island, the archipelago's best-known attraction.
Getting to Thousand Islands
✈
Flights
Fly into Toronto (YYZ) or Ottawa (YOW), then drive 2-3 hours to Kingston or Gananoque.
⏱
From London
~8 hours from London via Toronto, plus the drive.
🚕
Getting around
A car is useful for reaching towns along the river; boat tours handle the islands themselves.
Frequently asked questions
What is Boldt Castle?
An elaborate unfinished mansion on Heart Island, built in the early 1900s as a love story turned tragedy, now open to visitors via boat tour.
Can I visit the Thousand Islands from both Canada and the USA?
Yes — boat tours operate from Kingston, Ontario and from Gananoque, as well as from Alexandria Bay on the New York side.
How many islands are there really?
Over 1,800 islands are officially counted in the archipelago, ranging from tiny rocky outcrops to several square kilometres in size.
What is the best way to see the islands?
A boat cruise is the classic way to appreciate the scale and variety of the islands, with several tour lengths and stops available.
When is the best time to visit?
May to October for boat tours and warm weather; September brings fewer crowds and the start of autumn colour.
Traveler reviews
★★★★☆
The boat cruise from Gananoque was relaxing and the variety of islands, from tiny rocks to huge estates, was fascinating to see up close.
Howard P. · September 2024
★★★★★
Boldt Castle was surprisingly grand and the story behind it is quite moving. Kingston itself is a lovely waterfront town to spend a night in too.
Lindsey C. · July 2023
★★★★☆
Did the cruise from Alexandria Bay on the US side and got great views of the castle and dozens of smaller islands with cottages on them.
Frank Y. · August 2024
Ready to visit Thousand Islands?
Find the best hotels and experiences for your trip.
More dream destinations
