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Weather & Climate in Iwanuma, Japan
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Iwanuma experiences four distinct seasons with an average annual temperature of 55°F (13°C). Winters average 36°F in January while summers reach 73°F in July. The area gets 250 sunny days per year, above the national average. Annual precipitation totals 47.3 inches (wetter than the 38-inch national average). The city sits at an elevation of 16 feet.
Temperature
36°F Jan (2°C)
73°F Jul (23°C)
| Annual Average | 55.0°F |
| 2% above US avg | |
| January Average | 36°F (2°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 250 days/yr |
Geography
| Elevation | 16 ft (5 m) |
| Area | 110.1 sq mi (285.1 km²) |
| Population Density | 400/sq mi |
| Coordinates | 38.1047°N, 140.8594°W |
| Timezone | Asia/Tokyo |
Precipitation & Snow
Air Quality
Earthquake History
2,797 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M9.1.
| Mar 11, 2011 | 2011 Great Tohoku Earthquake, Japan | M9.1 | 134 km | 29 km |
| Mar 16, 2022 | 57 km ENE of Namie, Japan | M7.3 | 77 km | 41 km |
| Feb 13, 2021 | 73 km ENE of Namie, Japan | M7.1 | 91 km | 44 km |
| Apr 7, 2011 | 29 km ESE of Ishinomaki, Japan | M7.1 | 67 km | 42 km |
| May 26, 2003 | 27 km SSW of ?funato, Japan | M7.0 | 103 km | 68 km |
| Mar 20, 2021 | 30 km E of Ishinomaki, Japan | M7.0 | 79 km | 43 km |
| Jul 19, 2008 | 107 km E of Namie, Japan | M7.0 | 134 km | 22 km |
| May 1, 2021 | 30 km SSE of Onagawa Ch?, Japan | M6.9 | 65 km | 43 km |
| Jun 13, 2008 | 24 km WSW of Mizusawa, Japan | M6.9 | 103 km | 8 km |
| May 12, 2015 | 32 km SE of ?funato, Japan | M6.8 | 135 km | 35 km |
| Apr 11, 2011 | 17 km SSW of Ishikawa, Japan | M6.6 | 129 km | 11 km |
| Mar 14, 2010 | 59 km ENE of Namie, Japan | M6.5 | 76 km | 32 km |
| Dec 2, 2001 | 3 km NW of Hanamaki, Japan | M6.5 | 146 km | 124 km |
| Jun 18, 2019 | 31 km WSW of Tsuruoka, Japan | M6.4 | 134 km | 12 km |
| Nov 3, 2002 | 30 km SE of ?funato, Japan | M6.4 | 130 km | 39 km |
| Jul 23, 2011 | 21 km SSE of ?funato, Japan | M6.3 | 121 km | 41 km |
| Aug 4, 2019 | 61 km ENE of Namie, Japan | M6.3 | 76 km | 38 km |
| Jul 24, 2011 | 43 km NE of Namie, Japan | M6.3 | 63 km | 40 km |
| Jul 30, 2011 | 13 km SSE of Iwaki, Japan | M6.3 | 130 km | 38 km |
| Mar 11, 2011 | 30 km NNE of Namie, Japan | M6.3 | 52 km | 32 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Hurricane History
18 hurricanes (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 3.
| Year | Name | Category | Max Wind | Closest |
| 2024 | Jebi | Category 1 | 75 mph | 248 km |
| 2019 | Faxai | Category 2 | 92 mph | 163 km |
| 2019 | Hagibis | Category 1 | 81 mph | 83 km |
| 2016 | Lionrock | Category 1 | 75 mph | 290 km |
| 2011 | Roke | Category 1 | 81 mph | 286 km |
| 2005 | Mawar | Category 1 | 69 mph | 217 km |
| 2004 | Ma-on | Category 2 | 69 mph | 156 km |
| 2002 | Higos | Category 1 | 75 mph | 12 km |
| 2001 | Danas | Category 1 | 63 mph | 194 km |
| 2000 | Sonamu | Category 1 | 63 mph | 257 km |
| 2000 | Kirogi | Category 1 | 69 mph | 106 km |
| 1998 | Vicki | Category 2 | 63 mph | 135 km |
| 1998 | Stella | Category 1 | 63 mph | 235 km |
| 1996 | Violet | Category 1 | 81 mph | 208 km |
| 1995 | Oscar | Category 3 | 98 mph | 259 km |
| 1993 | Vernon | Category 1 | 75 mph | 115 km |
| 1981 | Thad | Category 1 | — | 244 km |
| 1981 | Gay | Category 1 | 75 mph | 243 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tsunami History
20 tsunamis recorded within 500 km. Highest wave on record: 39.3 m (129 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 2011 | HONSHU ISLAND | Earthquake | 39.3 m | 18,423 | 134 km |
| 1964 | NW. HONSHU ISLAND | Earthquake | 5.8 m | 36 | 146 km |
| 1835 | SANRIKU | Earthquake | 5.0 m | — | 94 km |
| 1861 | OFF MIYAGI | Earthquake | 3.9 m | — | 109 km |
| 2008 | ARATOZAWA, JAPAN | Eruption + Earthquake | 2.5 m | 23 | 103 km |
| 2016 | E. COAST HONSHU ISLAND | Earthquake | 1.4 m | — | 92 km |
| 1938 | OFF FUKUSHIMA PREFECTURE | Earthquake | 1.3 m | — | 107 km |
| 1938 | OFF FUKUSHIMA PREFECTURE | Earthquake | 1.3 m | — | 144 km |
| 1897 | SANRIKU | Earthquake | 1.0 m | — | 91 km |
| 1804 | NW. HONSHU ISLAND | Earthquake | 1.0 m | 450 | 132 km |
| 1959 | SANRIKU | Earthquake | 0.8 m | — | 136 km |
| 1938 | SANRIKU | Earthquake | 0.8 m | — | 135 km |
| 1936 | SANRIKU | Earthquake | 0.7 m | — | 118 km |
| 1978 | SANRIKU | Earthquake | 0.6 m | 28 | 103 km |
| 1938 | SANRIKU | Earthquake | 0.6 m | 1 | 134 km |
| 1938 | SANRIKU | Earthquake | 0.6 m | — | 125 km |
| 2022 | OFF FUKUSHIMA PREFECTURE | Earthquake | 0.3 m | 4 | 77 km |
| 2008 | OFF EAST COAST OF HONSHU ISLAND | Earthquake | 0.2 m | — | 134 km |
| 1933 | SANRIKU | Earthquake | 0.2 m | — | 135 km |
| 2019 | NIIGATA | Earthquake | 0.1 m | — | 135 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
15 volcanoes within 200 km. Closest: Zaozan [Zaosan] (37 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Zaozan [Zaosan] | Complex | 1,841 m (6,040 ft) | 1940 | 37 km |
| Azumayama | Stratovolcano(es) | 1,949 m (6,394 ft) | 1977 | 68 km |
| Naruko | Caldera | 470 m (1,542 ft) | 837 | 70 km |
| Adatarayama | Stratovolcano(es) | 1,728 m (5,669 ft) | 1996 | 72 km |
| Bandaisan | Stratovolcano | 1,816 m (5,958 ft) | 1888 | 89 km |
| Kurikomayama | Stratovolcano | 1,627 m (5,338 ft) | 1950 | 95 km |
| Chokaisan | Stratovolcano(es) | 2,236 m (7,336 ft) | 1974 | 131 km |
| Nasudake | Stratovolcano(es) | 1,915 m (6,283 ft) | 1963 | 135 km |
| Numazawa | Shield | 835 m (2,740 ft) | -3400 | 135 km |
| Takaharayama | Stratovolcano | 1,795 m (5,889 ft) | -4570 | 165 km |
| Akita-Komagatake | Stratovolcano(es) | 1,637 m (5,371 ft) | 1971 | 184 km |
| Omanago Group | Lava dome(s) | 2,341 m (7,680 ft) | -3050 | 188 km |
| Hiuchigatake | Stratovolcano | 2,356 m (7,730 ft) | 1544 | 189 km |
| Nantaisan | Stratovolcano | 2,486 m (8,156 ft) | -9540 | 192 km |
| Iwatesan | Complex | 2,038 m (6,686 ft) | 1919 | 195 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 36°F (2°C) | 1.5 in | Coldest, Driest |
| February | 37°F (3°C) | 1.9 in | |
| March | 42°F (5°C) | 2.7 in | |
| April | 52°F (11°C) | 3.7 in | |
| May | 60°F (16°C) | 3.9 in | |
| June | 66°F (19°C) | 5.3 in | |
| July | 73°F (23°C) | 5.9 in | |
| August | 76°F (25°C) | 6.2 in | Warmest |
| September | 70°F (21°C) | 7.4 in | Wettest |
| October | 60°F (15°C) | 4.7 in | |
| November | 50°F (10°C) | 2.7 in | |
| December | 41°F (5°C) | 1.5 in |
Iwanuma has a seasonal temperature swing of 41°F / from 36°F in January to 76°F in August. Total annual precipitation is 47.3 inches, with September being the wettest month (7.4") and January the driest (1.5").