The Izu Peninsula juts into the Pacific about 100 kilometers southwest of Tokyo, a volcanic landmass where hot springs steam alongside rugged sea cliffs, waterfall-laced gorges, and some of Japan's finest white-sand beaches. This is where Tokyoites escape for long weekends of soaking in onsen, feasting on freshly caught kinmedai (golden-eye snapper) and sakura ebi (cherry blossom shrimp), and exploring a coastline that swings from surf breaks around Shimoda to the dramatic sea caves of Dogashima. History runs deep here too: Shimoda is where Commodore Perry's black ships landed in the 1850s, effectively ending Japan's centuries of isolation, and the old onsen town of Shuzenji still feels like something out of a Kawabata novel.
Your best window for Izu falls in two stretches: mid-April through late June, and late September through mid-November. The spring-into-early-summer window is the top pick, bringing comfortable hiking temperatures, the Black Ship Festival in Shimoda during the third weekend of May, and hydrangeas carpeting the hillsides by June. Be aware that late June brings the start of tsuyu (rainy season), so plan outdoor days earlier in the window if you can. The autumn window is a strong alternative: temperatures settle into a pleasant range, crowds thin slightly from the summer peak, and by late November the peninsula's maples turn vivid shades of red and gold around Shuzenji and the Amagi highlands. If you're chasing cherry blossoms, Kawazu's early-blooming sakura typically flower from early February through early March, well before the rest of Japan.
Spring in Izu, Japan
Spring is when the Izu Peninsula shakes off winter's quiet. Cherry blossoms sweep through the coastal towns in late March and early April, and by mid-spring the hillsides above Shuzenji and along the Jogasaki Coast are bright with fresh green. Afternoon highs reach 67.4°F (19.7°C), warm enough for comfortable walks along the Kawazu Seven Waterfalls trail or the 10-kilometer Jogasaki coastal path with its dramatic suspension bridge. Mornings can still be brisk at 47.7°F (8.7°C), so layers are essential for early starts.
May is one of the peninsula's liveliest months. Shimoda hosts the Kurofune Matsuri (Black Ship Festival) on the third weekend of May, a celebration that commemorates Commodore Perry's arrival with parades, historical reenactments, live music, and a memorial ceremony at Gyokusenji Temple. Around the same time, azaleas bloom across Komuroyama Park. Showers pop up on roughly two to four days through the season, but they're usually brief enough that they won't derail a day of sightseeing. Pack a compact rain jacket and you'll be fine.
Golden Week, the cluster of national holidays from late April through early May, does draw domestic tourists to Izu's onsen towns and beaches, so book ryokan well ahead if you're visiting during that stretch. Outside that holiday burst, spring crowds stay moderate and accommodation prices offer good value. The long daylight hours, with the sun not setting until after 6:30pm by May, give you plenty of time to explore the western coast's sunset views over Suruga Bay before heading back to your inn for a multi-course seafood kaiseki dinner.
Summer in Izu, Japan
Summer on the Izu Peninsula is beach season, fireworks season, and sweat season, all rolled into one. The official swimming window at Shimoda's beaches opens in mid-July and runs through August, and the white sand at Shirahama draws surfers, snorkelers, and families from Tokyo. Seasonal highs climb to 85.4°F (29.7°C) with lows staying warm at 70.7°F (21.5°C), and humidity hovers in the mid-to-upper 60s, making afternoons feel heavy. June marks the start of tsuyu, Japan's rainy season, and wet days are more frequent, with precipitation expected roughly two to five days through the season.
The cultural payoff for braving the heat is real. Ito's Anjinsai festival, typically held in early-to-mid August, honors the construction of Japan's first Western-style ship with three days of yosakoi dance competitions, taiko drumming battles, and a massive fireworks display over Sagami Bay. For two weeks surrounding the festival, nightly fireworks light up the Ito waterfront. Atami runs its own regular summer fireworks series, and in late July the coastal town of Dogashima reenacts a local legend by setting a pirate ship ablaze on the water. The energy across the peninsula during these weeks is infectious.
Early-to-mid August brings peak heat, with highs reaching 91.2°F (32.9°C) and overnight lows of 75.9°F (24.4°C). This is also typhoon season, so keep an eye on forecasts, especially if you're planning boat trips around Cape Irozaki or kayaking off Shimoda. June is the busiest month for tourism, and accommodation prices run higher than usual across the board. If the humidity gets to you, duck into one of the peninsula's many onsen for a soak, or retreat to the cooler Amagi highlands for a forest hike near Joren Waterfall.
Fall in Izu, Japan
Autumn brings Izu back into its comfort zone. September still carries some summer warmth, but by October the air cools and the light turns golden along the coast. Highs average a pleasant 74.8°F (23.8°C), while lows settle to 56.7°F (13.7°C), ideal for long days of hiking, onsen hopping, and coastal exploring without breaking a sweat. The Jogasaki Coast trail is especially rewarding in fall, with crisp ocean breezes and clear sightlines to Izu Oshima island.
Autumn foliage arrives later on the peninsula than in much of Japan; the season doesn't typically start until mid-November, with late November considered the best time for koyo viewing around Shuzenji's bamboo grove and the Amagi mountain passes. The Shuzenji area's red maples reflected in the Katsura River make one of Izu's most photographed scenes. Earlier in the season, October's Sports Day holiday in mid-month brings a bump in visitors, and the peninsula ranks as the second busiest tourism period behind summer. Precipitation appears every few days, roughly two to three times, but extended washouts are uncommon.
This is prime seafood season along the west coast. Suruga Bay's deep waters yield prized catches, and local ryokan feature elaborate kaiseki courses built around the season's freshest fish. A light jacket is enough for most October days, but by late November you'll want an extra layer for evening strolls through the onsen towns. The sun sets before 5pm by November, so plan your scenic drives and waterfall hikes for the morning hours when the light is best.
Winter in Izu, Japan
Winter quiets the peninsula down to a murmur. Many of the smaller seaside restaurants and beach-facing shops in Shimoda close or reduce hours, and the narrow mountain roads through the interior feel empty. But that stillness is part of the appeal for onsen lovers: soaking in an outdoor rotenburo with cold air on your face and steam rising around you is one of Japan's great winter pleasures, and Izu's hot spring towns, from Atami to Shuzenji to Dogashima, deliver it without the crowds.
Highs reach just 54.3°F (12.4°C), with mornings dropping to 33.9°F (1.1°C), cold enough to see your breath on a walk through Shuzenji's bamboo-lined paths. Snow is essentially nonexistent at sea level, so roads stay clear, but you'll want a warm coat, hat, and gloves for any time spent outdoors. Precipitation is light, with rain appearing only now and again, roughly two to three days. Days are short, with barely ten hours of daylight in December, so build your itinerary around the earlier sunsets.
The standout winter event is the Kawazu Cherry Blossom Festival, which runs from early February through early March. Kawazu's sakura variety blooms weeks before the rest of Japan's cherry trees, drawing nearly two million visitors along four kilometers of pink-canopied riverbank. Night illuminations add a magical quality after dark, and festival stalls sell local citrus, dried seafood, and miniature cherry trees you can take home. January's quieter weeks are also an excellent time to visit the Inatori Hina doll and hanging ornament festival, a century-old tradition that runs from mid-January through the end of March. Pack thermal layers and plan for cozy evenings at your ryokan with a pot of local Shizuoka green tea.
At a Glance
Monthly weather, visitor crowds, air quality, holidays, and daylight hours to help you plan your trip.
Travel Tips & Safety for Izu, Japan
Getting to Izu is straightforward from Tokyo. The Tokaido Shinkansen reaches Atami in about 50 minutes, and from there the Izukyu Railway line runs down the eastern coast to Shimoda. The Japan Rail Pass covers trains as far as Ito, but you'll need to pay a supplement on the Izukyu Railway beyond that point. For the western coast and interior highlands, a rental car is the practical choice, as bus service to smaller towns is infrequent. Roads are curvy through the mountains but traffic is generally light.
Izu is one of the safest corners of an already very safe country. The main hazards are natural: typhoon season runs from roughly July through October, and strong storms can disrupt ferries and coastal roads. Mountain hiking trails around Amagi can be slippery after rain, so wear proper footwear. Jellyfish occasionally appear at beaches in late summer, so check local signage before swimming. Tap water is safe to drink throughout the peninsula.