# Ōnan, Shimane

Ōnan (邑南町, Ōnan-chō) is a town located in Ōchi District, Shimane Prefecture, Japan. As of 31 July 2023, the town had an estimated population of 9,838 in 4712 households and a population density of 23 persons per km². The total area of the town is 419.29 square kilometres (161.89 sq mi).

## Geography

Ōnan is located in west-central Shimane, in the Chugoku Mountains bordered by Hiroshima Prefecture to the south.

## Neighboring municipalities

Hiroshima Prefecture
* Akitakata
* Kitahiroshima
* Miyoshi
Shimane Prefecture
* Gōtsu
* Hamada
* Kawamoto
* Misato

### Climate

Ōnan has a humid subtropical climate (Köppen climate classification Cfa) with very warm summers and cool winters. Precipitation is abundant throughout the year. The average annual temperature in Ōnan is 12.1 °C (53.8 °F). The average annual rainfall is 1,885.0 mm (74.21 in) with July as the wettest month. The temperatures are highest on average in August, at around 24.3 °C (75.7 °F), and lowest in January, at around 0.7 °C (33.3 °F). The highest temperature ever recorded in Ōnan was 36.5 °C (97.7 °F) on 8 August 1994; the coldest temperature ever recorded was −16.3 °C (2.7 °F) on 28 February 1981.
Climate data for Mizuho, Ōnan (1991−2020 normals, extremes 1978−present) :
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °C (°F) | 16.7 (62.1) | 20.5 (68.9) | 23.7 (74.7) | 30.3 (86.5) | 32.2 (90.0) | 33.9 (93.0) | 36.4 (97.5) | 36.5 (97.7) | 35.0 (95.0) | 30.1 (86.2) | 25.1 (77.2) | 18.8 (65.8) | 36.5 (97.7) |
| Mean daily maximum °C (°F) | 5.2 (41.4) | 6.7 (44.1) | 11.5 (52.7) | 17.9 (64.2) | 23.0 (73.4) | 25.7 (78.3) | 29.1 (84.4) | 30.5 (86.9) | 25.9 (78.6) | 20.3 (68.5) | 14.3 (57.7) | 7.8 (46.0) | 18.2 (64.7) |
| Daily mean °C (°F) | 0.7 (33.3) | 1.4 (34.5) | 5.0 (41.0) | 10.6 (51.1) | 15.7 (60.3) | 19.6 (67.3) | 23.6 (74.5) | 24.3 (75.7) | 20.0 (68.0) | 13.6 (56.5) | 7.9 (46.2) | 2.8 (37.0) | 12.1 (53.8) |
| Mean daily minimum °C (°F) | −2.9 (26.8) | −3.0 (26.6) | −0.9 (30.4) | 3.6 (38.5) | 8.9 (48.0) | 14.6 (58.3) | 19.4 (66.9) | 19.9 (67.8) | 15.4 (59.7) | 8.2 (46.8) | 2.7 (36.9) | −1.1 (30.0) | 7.1 (44.7) |
| Record low °C (°F) | −12.6 (9.3) | −16.3 (2.7) | −10.1 (13.8) | −5.9 (21.4) | −1.9 (28.6) | 3.9 (39.0) | 9.2 (48.6) | 10.9 (51.6) | 2.1 (35.8) | −1.9 (28.6) | −5.0 (23.0) | −11.3 (11.7) | −16.3 (2.7) |
| Average precipitation mm (inches) | 151.8 (5.98) | 130.9 (5.15) | 145.9 (5.74) | 126.3 (4.97) | 139.7 (5.50) | 194.6 (7.66) | 260.9 (10.27) | 169.9 (6.69) | 201.7 (7.94) | 112.7 (4.44) | 95.5 (3.76) | 155.3 (6.11) | 1,885 (74.21) |
| Average snowfall cm (inches) | 115 (45) | 86 (34) | 21 (8.3) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (0.4) | 49 (19) | 272 (107) |
| Average precipitation days (≥ 1.0 mm) | 18.3 | 15.3 | 14.5 | 11.3 | 10.1 | 12.3 | 13.5 | 10.7 | 11.2 | 9.4 | 11.4 | 17.0 | 155 |
| Average snowy days (≥ 3 cm) | 9.8 | 7.5 | 1.5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.1 | 3.9 | 22.8 |
| Mean monthly sunshine hours | 66.0 | 82.2 | 137.8 | 177.8 | 200.0 | 144.2 | 149.4 | 182.5 | 140.7 | 146.3 | 109.3 | 75.8 | 1,612 |
| Source: Japan Meteorological Agency ||||||||||||||

### Demographics

Per Japanese census data, the population of Ōnan in 2020 was 10,163 people. Ōnan has been conducting censuses since 1960.

## History

The area of Ōnan was part of ancient Iwami Province. During the Edo Period, the area was divided between of the holdings of Hamada Domain and direct territory of the Tokugawa shogunate. After the Meiji restoration, villages were established within Ōchi District, Shimane on April 1, 1889 with the creation of the modern municipalities system. The town of Ōnan was formed on October 1, 2004, from the merger of the towns of Iwami, Mizuho, and the village of Hasumi.

## Government

Ōnan has a mayor-council form of government with a directly elected mayor and a unicameral town council of 13 members. Ōnan, collectively with the towns of Kawamoto and Misato, contributes one member to the Shimane Prefectural Assembly. In terms of national politics, the town is part of the Shimane 2nd district of the lower house of the Diet of Japan.

## Economy

Ōnan is a very rural area, with an economy based on agriculture and forestry.

## Education

Ōnan has eight public elementary school and three public junior high schools operated by the town government, and one public high school operated by the Shimane Prefectural Board of Education.

## Transportation
### Railway

Following the closure of the JR West Sankō Line on April 1, 2018, Ōnan no longer has any passenger railway service. The nearest train station is Gōtsu Station on the JR West San'in Main Line.
JR West - Sankō Line
* Uzui - < Ikawashi > - Kuchiba - Gōbira - Sakugiguchi

### Highways

* Hamada Expressway
* National Route 261

## Notable people from Ōnan

* Tetsuo Saito, politician