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Weather & Climate in Koshimizu, Japan
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Koshimizu has a cool climate with an average annual temperature of 44°F (6°C). Winters average 20°F in January while summers reach 64°F in July. The area gets 270 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 36.2 inches. The area receives 8.6 inches of snow annually. The city sits at an elevation of 62 feet.
Temperature
20°F Jan (-7°C)
64°F Jul (18°C)
| Annual Average | 43.5°F |
| 19% below US avg | |
| January Average | 20°F (-7°C) |
| July Average | 64°F (18°C) |
| Sunny Days | 270 days/yr |
Geography
| Elevation | 62 ft (19 m) |
| Area | 110.8 sq mi (286.9 km²) |
| Population Density | 45/sq mi |
| Coordinates | 43.8590°N, 144.4651°W |
| Timezone | Asia/Tokyo |
Precipitation & Snow
Air Quality
Earthquake History
578 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M7.6.
| Jan 15, 1993 | 52 km NE of Otofuke, Japan | M7.6 | 88 km | 102 km |
| Oct 8, 2003 | 39 km SSE of Kushiro, Japan | M6.7 | 135 km | 32 km |
| Jan 18, 2005 | 40 km E of Kushiro, Japan | M6.3 | 107 km | 42 km |
| Aug 31, 1994 | 36 km SSE of Yuzhno-Kurilsk, Russia | M6.2 | 125 km | 76 km |
| May 12, 1999 | 44 km W of Kushiro, Japan | M6.2 | 105 km | 103 km |
| Jan 15, 1993 | 17 km W of Kushiro, Japan | M6.1 | 101 km | 112 km |
| Apr 11, 2004 | 38 km E of Kushiro, Japan | M6.1 | 109 km | 42 km |
| Nov 15, 1997 | 19 km NNW of Shibetsu, Japan | M6.1 | 45 km | 161 km |
| Apr 26, 2001 | 37 km SE of Nemuro, Japan | M6.0 | 145 km | 86 km |
| Feb 25, 2023 | Hokkaido, Japan region | M6.0 | 123 km | 55 km |
| Nov 30, 1995 | 30 km NW of Otrada, Russia | M6.0 | 103 km | 137 km |
| Jul 1, 2007 | 32 km W of Shibetsu, Japan | M5.8 | 31 km | 130 km |
| Apr 13, 2001 | 69 km SSW of Nemuro, Japan | M5.6 | 143 km | 33 km |
| Sep 28, 2003 | 48 km SE of Kushiro, Japan | M5.6 | 139 km | 33 km |
| Apr 24, 2018 | 12 km ENE of Nemuro, Japan | M5.5 | 116 km | 83 km |
| Mar 30, 2007 | 13 km ENE of Otrada, Russia | M5.5 | 127 km | 100 km |
| Mar 11, 2005 | 27 km ENE of Kushiro, Japan | M5.5 | 88 km | 54 km |
| Feb 17, 2004 | 27 km SE of Nemuro, Japan | M5.5 | 135 km | 40 km |
| Sep 26, 2024 | 30 km SE of Akkeshi, Japan | M5.5 | 126 km | 50 km |
| Jan 30, 1990 | 36 km SSW of Nemuro, Japan | M5.5 | 124 km | 41 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Hurricane History
1 hurricane (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 1.
| Year | Name | Category | Max Wind | Closest |
| 2000 | Sonamu | Category 1 | 58 mph | 265 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tsunami History
5 tsunamis recorded within 500 km. Highest wave on record: 6.0 m (20 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1973 | HOKKAIDO ISLAND | Earthquake | 6.0 m | — | 130 km |
| 1938 | E. HOKKAIDO ISLAND | Earthquake | 0.9 m | 1 | 32 km |
| 1956 | NE. HOKKAIDO ISLAND | Earthquake | 0.4 m | — | 57 km |
| 2004 | HOKKAIDO ISLAND | Earthquake | 0.1 m | — | 109 km |
| 1961 | SE. HOKKAIDO ISLAND | Earthquake | 0.1 m | — | 141 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
11 volcanoes within 200 km. Closest: Kussharo (27 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Kussharo | Caldera | 574 m (1,883 ft) | 1320 | 27 km |
| Mashu | Caldera | 857 m (2,812 ft) | 1080 | 33 km |
| Shiretoko-Iozan | Stratovolcano | 1,562 m (5,125 ft) | 1936 | 64 km |
| Akan | Caldera | 1,499 m (4,918 ft) | 2008 | 64 km |
| Tomariyama [Golovnin] | Caldera | 535 m (1,755 ft) | 1848 | 83 km |
| Raususan [Mendeleev] | Stratovolcano | 882 m (2,894 ft) | 1880 | 102 km |
| Maruyama | Stratovolcano(es) | 2,013 m (6,604 ft) | 1898 | 125 km |
| Taisetsuzan | Stratovolcano(es) | 2,291 m (7,516 ft) | 1739 | 131 km |
| Ruruidake [Smirnov] | Stratovolcano | 1,486 m (4,875 ft) | Unknown | 149 km |
| Tokachidake | Stratovolcano(es) | 2,077 m (6,814 ft) | 2004 | 151 km |
| Chachadake [Tiatia] | Stratovolcano | 1,822 m (5,978 ft) | 1981 | 153 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 20°F (-7°C) | 2.3 in | |
| February | 20°F (-7°C) | 1.6 in | Coldest, Driest |
| March | 28°F (-2°C) | 2.5 in | |
| April | 41°F (5°C) | 2.6 in | |
| May | 50°F (10°C) | 3.0 in | |
| June | 57°F (14°C) | 2.8 in | |
| July | 64°F (18°C) | 3.4 in | |
| August | 67°F (20°C) | 4.3 in | Warmest |
| September | 61°F (16°C) | 5.1 in | Wettest |
| October | 51°F (11°C) | 3.6 in | |
| November | 38°F (4°C) | 2.9 in | |
| December | 26°F (-3°C) | 2.2 in |
Koshimizu has a seasonal temperature swing of 48°F / from 20°F in February to 67°F in August. Total annual precipitation is 36.2 inches, with September being the wettest month (5.1") and February the driest (1.6").