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Isumi, Japan
Chiba · Japan
Isumi is a mid-size city in Chiba, Japan with a population of 35,544. Elevation: 3 ft (1 m). Average temperature: 60°F (15°C).
Data updated June 2026
Discover Isumi, Japan
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People
Economy
BHousing
A+Climate
| Population | 35,544 |
| Population Density | 585 / sq mi |
| Elevation | 3 ft (1 m) |
| Coordinates | 35.2301°, 140.4049° |
| Timezone | Asia/Tokyo |
| Country | 🇯🇵 Japan |
| State / Province | Chiba |
| Average Temperature | 60°F (15°C) |
| January Average | 42°F (6°C) |
| July Average | 75°F (24°C) |
| Annual Precipitation | 68.0 inches (1,728 mm) |
| Annual Snowfall | 0.0 inches (0 cm) |
| Median Household Income | $35,400 |
| Median Age | 47.5 years |
About Isumi
Isumi is a mid-size city in Japan (Chiba) with a population of 35,544. The city sits at an elevation of 3 feet (1 meters) above sea level. The average annual temperature is 60°F (15°C). Temperatures range from 42°F in January to 75°F in July. Annual precipitation averages 68.0 inches. The timezone is Asia/Tokyo.
Population
Language Spoken at Home
Social Characteristics
Isumi vs Japan Average
Income: Isumi vs Japan
Commute Mode
Income
| Median HH Income | $35,400 |
| 53% below Japan avg |
Employment & Poverty
| Unemployment | 2.5% |
| 31% below Japan avg | |
| Establishments (County) | 1,137 |
Business (County)
Tax & Cost of Living
Commute & Transportation
Walkability
Home Value Sources
Ownership Split
Home Values
| Census Median | $102,000 |
| 64% below Japan avg |
Real Estate Market (Redfin)
Rental Costs
| Census Median Rent | $510 |
| 56% below Japan avg |
Ownership & Property
| Housing Units | 14,218 |
Property Tax
Climate in Isumi
Isumi has an average annual temperature of 0°C (32°F). The hottest month is Jan (0°C), the coldest is Jan (0°C). Average annual precipitation is 2114 mm.
Temperature
| Annual Average | 59.7°F |
| 11% above Japan avg | |
| January Average | 42°F (6°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 213 days/yr |
Geography
| Elevation | 3 ft (1 m) |
| Area | 60.8 sq mi (157.5 km²) |
| Population Density | 585/sq mi |
| Coordinates | 35.2301°N, 140.4049°W |
| Timezone | Asia/Tokyo |
Precipitation & Snow
Air Quality
Tsunami History
20 tsunamis recorded within 500 km. Highest wave on record: 13.0 m (43 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1923 | SAGAMI BAY | Earthquake | 13.0 m | 105,385 | 84 km |
| 1703 | OFF SW BOSO PENINSULA | Earthquake | 11.7 m | 5,233 | 81 km |
| 1677 | OFF SE. BOSO PENINSULA | Earthquake | 8.0 m | 500 | 103 km |
| 1495 | KAMAKURA, SAGAMI BAY, TOKAIDO | Earthquake | 5.0 m | 200 | 84 km |
| 1732 | KUJUKURI BEACH, JAPAN | Earthquake | 2.0 m | - | 36 km |
| 1670 | BOSO, JAPAN | Earthquake | 2.0 m | - | 62 km |
| 1433 | OFF IZU-OSHIMA | Earthquake | 2.0 m | - | 90 km |
| 1980 | HONSHU ISLAND | Earthquake | 0.6 m | - | 121 km |
| 1923 | KASHIMA, JAPAN | Earthquake | 0.4 m | - | 128 km |
| 1978 | TOKAIDO | Earthquake | 0.4 m | 25 | 114 km |
| 1923 | RYUKYU ISLANDS | Earthquake | 0.3 m | - | 41 km |
| 1990 | JAPAN | Earthquake | 0.2 m | - | 120 km |
| 2000 | HONSHU: S COAST | Earthquake | 0.1 m | - | 146 km |
| 1909 | OFF BOSO PENINSULA | Earthquake | - | - | 129 km |
| 1909 | OFF BOSO PENINSULA | Earthquake | - | - | 129 km |
| 1855 | TOKAIDO | Earthquake | - | 6,757 | 72 km |
| 1782 | ODAWARA, SAGAMI BAY | Eruption + Earthquake | - | - | 66 km |
| 1642 | BOSO, JAPAN | Earthquake | - | - | 18 km |
| 1633 | SAGAMI BAY | Earthquake | - | 150 | 110 km |
| 1602 | BOSO, JAPAN | Eruption + Earthquake | - | - | 17 km |
Nearby Volcanoes
15 volcanoes within 200 km. Closest: Izu-Oshima (108 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Izu-Oshima | Stratovolcano | 758 m (2,487 ft) | 1990 | 108 km |
| Izu-Tobu | Pyroclastic cone(s) | 1,406 m (4,613 ft) | 1989 | 125 km |
| Hakoneyama | Complex | 1,438 m (4,718 ft) | 2015 | 126 km |
| Toshima | Stratovolcano | 508 m (1,667 ft) | -4550 | 130 km |
| Niijima | Lava dome(s) | 432 m (1,417 ft) | 886 | 139 km |
| Miyakejima | Stratovolcano | 775 m (2,543 ft) | 2010 | 150 km |
| Fujisan | Stratovolcano | 3,776 m (12,388 ft) | 1708 | 153 km |
| Kozushima | Lava dome(s) | 572 m (1,877 ft) | 838 | 160 km |
| Mikurajima | Stratovolcano | 851 m (2,792 ft) | -4100 | 168 km |
| Akagisan | Stratovolcano | 1,828 m (5,997 ft) | Unknown | 184 km |
| Nantaisan | Stratovolcano | 2,486 m (8,156 ft) | -9540 | 189 km |
| Omanago Group | Lava dome(s) | 2,341 m (7,680 ft) | -3050 | 192 km |
| Takaharayama | Stratovolcano | 1,795 m (5,889 ft) | -4570 | 194 km |
| Harunasan | Stratovolcano | 1,449 m (4,754 ft) | 550 | 197 km |
| Nikko-Shiranesan | Shield | 2,578 m (8,458 ft) | 1952 | 198 km |
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 42°F (6°C) | 2.9 in | Coldest |
| February | 43°F (6°C) | 3.8 in | |
| March | 48°F (9°C) | 5.8 in | |
| April | 57°F (14°C) | 5.6 in | |
| May | 64°F (18°C) | 6.1 in | |
| June | 69°F (21°C) | 7.9 in | |
| July | 75°F (24°C) | 5.0 in | |
| August | 78°F (26°C) | 5.6 in | Warmest |
| September | 74°F (23°C) | 8.4 in | |
| October | 65°F (18°C) | 8.9 in | Wettest |
| November | 56°F (13°C) | 5.4 in | |
| December | 47°F (8°C) | 2.8 in | Driest |
Isumi has a seasonal temperature swing of 36°F / from 42°F in January to 78°F in August. Total annual precipitation is 68.0 inches, with October being the wettest month (8.9") and December the driest (2.8").
Schools in Isumi
1 public schools (NCES 2022-23 data).
| School | Level | Enrollment | Teachers | Student/Teacher |
|---|---|---|---|---|
| Namihana Elementary School | - | - | - | - |
Radio Stations near Isumi
0 stations within ~55 km.
| Station | Genre | Quality |
|---|
Museums in Isumi
| Name | Type | Address | Phone | Annual Revenue |
|---|---|---|---|---|
| Art House Asobara no Tani | ||||
| Ichihara Lakeside Museum | ||||
| いすみ市郷土資料館（田園の美術館） | ||||
| 千葉県いすみ環境と文化のさとセンター | ||||
| 千葉県立中央博物館分館海の博物館 | ||||
| 千葉県立中央博物館大多喜城分館 | ||||
| 史跡長柄横穴群資料館 | ||||
| 商い資料館 | ||||
| 国際上総埴生美術館 | ||||
| 大多喜町 天然ガス記念館 | ||||
| 市原市水と彫刻の丘 | ||||
| 御宿町歴史民俗資料館 | ||||
| 房総中央鉄道館 | ||||
| 月の砂漠記念館 | ||||
| 白子町歴史民俗資料室 | ||||
| 睦沢町立歴史民俗資料館 | ||||
| 研修館 | ||||
| 茂原市立美術館・郷土資料館 | ||||
| 誕生寺宝物館 | ||||
| 釜屋 | ||||
| 長南町郷土資料館 | ||||
| 麻雀博物館 | ||||
| 黒汐資料館 |
Libraries in Isumi
| Name | Address | Staff | Annual Visits | Circulation | Collection | Programs |
|---|---|---|---|---|---|---|
| 勝浦市立図書館 | 0.0 | |||||
| 大多喜町立大多喜図書館天賞文庫 | 0.0 |
Train Stations in Isumi
1 train stations within city radius - OpenStreetMap data
Airports Near Isumi
13 airports within the area.
| Airport | IATA | Type |
|---|---|---|
| Narita International Airport | NRT | Large Airport |
| Tokyo Haneda International Airport | HND | Large Airport |
| JGSDF Kisarazu Airfield | - | Medium Airport |
| JMSDF Shimofusa Air Base | - | Medium Airport |
| JMSDF Tateyama Air Base | - | Medium Airport |
| Iwabuchi Watergate Auxiliary Airfield | - | Small Airport |
| JGSDF Narashino Airfield | - | Small Airport |
| Kisarazu Nakajima Auxiliary Airfield / Kisarazu Heliport | - | Small Airport |
| Kozaki Airfield | - | Small Airport |
| Otone Airfield | - | Small Airport |
| Ryugasaki Airfield | - | Small Airport |
| Tokyo Flight Park Moriya Airstrip | - | Small Airport |
| Urayasu Emergency Runway | - | Small Airport |
Post Offices in Isumi
1 post offices.
| Post Office | Address |
|---|---|
| Namihana Post Office |
Quick Facts
🇯🇵 About Japan
Public Holidays in Japan
16 public holidays this year
Frequently Asked Questions About Isumi
What is the population of Isumi?
Isumi has a population of 35,544 residents and is located in Japan. The population density is 585 people per square mile, spread across 60.8 square miles. The median age of residents is 47.5 years, which is older than the national median of 38.9 years.
Is Isumi expensive to live in?
The median household income is $35,400, 53% below the national average of $75,149. The median home value is $102,000 (64% below the U.S. median). Renters pay a median of $510 per month, below the national average of $1,163. The home price-to-income ratio is 2.9x, indicating housing is reasonably affordable relative to local income levels.
What is the weather like in Isumi?
Isumi enjoys a temperate climate with an average annual temperature of 60°F (15°C). Winter temperatures average 42°F in January, while summers reach an average of 75°F in July. The area receives 213 sunny days per year. Annual rainfall totals 68.0 inches.
How is the job market in Isumi?
The job market in Isumi is very strong, with unemployment at just 2.5% / well below the national rate of 3.6%. There are 1,137 business establishments in the area.
How much does housing cost in Isumi?
The median home value in Isumi is $102,000. For renters, the median monthly rent is $510.