Niihama climate
Niihama (Japan) has a humid subtropical climate (Köppen Cfa). The average temperature over the year is 17 °C62 °F, and about 1,699 mm67 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Niihama climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin |
|---|---|---|---|---|
| Jan | 948 | 337 | 642 | 532.1 |
| Feb | 1151 | 338 | 744 | 793.1 |
| Mar | 1457 | 542 | 1050 | 1124.4 |
| Apr | 1967 | 1050 | 1558 | 1335.2 |
| May | 2475 | 1559 | 1967 | 1646.5 |
| Jun | 2781 | 2067 | 2374 | 2489.8 |
| Jul | 3087 | 2475 | 2781 | 25810 |
| Aug | 3289 | 2576 | 2883 | 1576.2 |
| Sep | 2883 | 2170 | 2577 | 2048.0 |
| Oct | 2373 | 1660 | 1967 | 1375.4 |
| Nov | 1763 | 1050 | 1457 | 803.1 |
| Dec | 1152 | 541 | 847 | 732.9 |
| Year | 3289 | 337 | 1762 | 1,69967 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 81% | 62% | 2.6 | 10:07 |
| Feb | 79% | 64% | 3.2 | 10:55 |
| Mar | 77% | 63% | 4.2 | 11:53 |
| Apr | 76% | 64% | 5.0 | 12:59 |
| May | 77% | 70% | 5.2 | 13:55 |
| Jun | 82% | 83% | 4.5 | 14:24 |
| Jul | 84% | 74% | 5.0 | 14:12 |
| Aug | 81% | 64% | 5.2 | 13:24 |
| Sep | 82% | 69% | 4.1 | 12:20 |
| Oct | 80% | 61% | 3.5 | 11:16 |
| Nov | 80% | 59% | 2.7 | 10:21 |
| Dec | 81% | 60% | 2.3 | 9:54 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Niihama is like
The warmest month is August, with an average high of 32 °C89 °F and a low of 25 °C76 °F. The coldest is January, when highs average 9 °C48 °F and lows 3 °C37 °F. Seasons are strongly marked: the warmest month is on average 22.3 °C40.1 °F warmer than the coldest.
It is wet, with about 1,699 mm67 in of precipitation per year. The wettest three-month stretch is May–July, which brings 39% of the annual total. The wettest month is July (258 mm10 in), the driest is January (53 mm2.1 in).
Relative humidity ranges from 76% in April to 84% in July. The clearest skies (lowest average cloud amount, 59%) are typical of November. Average wind speed near the ground ranges from 4 km/h (3 mph) in June to 8 km/h (5 mph) in January. Daylight lasts from about 9.9 hours in December to 14.4 hours in June.
Best time to visit Niihama
Based on these averages, the most comfortable months for sightseeing and outdoor activities are October and November. Average highs then reach 17 °C63 °F to 23 °C73 °F. Precipitation is 80 mm3.1 in to 137 mm5.4 in per month.
The most challenging month is July, which is hot, with average highs of 30 °C87 °F, very wet (258 mm10 in) and humid (84% relative humidity).
Comfort score: months are ranked by how close they come to an ideal. That means an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Niihama
- Winter (December–February) — highs 948 to 11 °C52 °F, lows 337 to 5 °C41 °F, about 68 mm2.7 in of precipitation a month. Pack a warm coat, layers and closed shoes.
- Spring (March–May) — highs 1457 to 24 °C75 °F, lows 542 to 15 °C59 °F, about 136 mm5.4 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket and an umbrella or light rain jacket.
- Summer (June–August) — highs 2781 to 32 °C89 °F, lows 2067 to 25 °C76 °F, about 221 mm8.7 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses and a good rain jacket or umbrella and quick-drying shoes.
- Autumn (September–November) — highs 1763 to 28 °C83 °F, lows 1050 to 21 °C70 °F, about 140 mm5.5 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket and an umbrella or light rain jacket.
How Niihama compares
The nearest larger place is Imabari, about 31 km to the northwest. Compared with it, Niihama has practically the same average temperature. It receives a similar amount of precipitation.
World Climates covers 111 places in Japan. By annual mean temperature, Niihama is the 24th warmest of them. By annual precipitation, it is the 53rd wettest. See all of them on the Japan climate page.
Some places in other countries have a very similar pattern of temperature and rainfall. The closest matches are Chongming (China, Cfa), Ningbo (China, Cfa) and Cixi (China, Cfa).
The same NASA POWER grid cell also contains Saijō (pop. 104,791). Their long-term averages in this dataset are essentially the same as for Niihama, so they do not have separate pages.
Nearby places
- Climate in Imabari 31 km · 17 °C62 °F · 1,699 mm67 in
- Climate in Shinagawa 45 km · 14 °C57 °F · 2,059 mm81 in
- Climate in Kochi 50 km · 18 °C64 °F · 2,190 mm86 in
- Climate in Matsuyama 52 km · 17 °C62 °F · 1,621 mm64 in
- Climate in Fukuyama 58 km · 16 °C61 °F · 1,526 mm60 in
- Climate in Kure 74 km · 16 °C61 °F · 1,621 mm64 in
- Climate in Takamatsu 80 km · 16 °C61 °F · 1,466 mm58 in
- Climate in Hiroshima 93 km · 15 °C60 °F · 1,556 mm61 in
Frequently asked questions
What is the warmest month in Niihama?
August is the warmest month in Niihama. Its average high is 32 °C (89 °F) and its average low is 25 °C (76 °F).
What is the coldest month in Niihama?
January is the coldest month. Its average high is 9 °C (48 °F) and its average low is 3 °C (37 °F).
When does it rain the most in Niihama?
July is the wettest month with about 258 mm (10.2 in) of precipitation. January is the driest with about 53 mm (2.1 in).
What is the best time to visit Niihama?
Judging by long-term averages, the most comfortable months are October and November.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station. So they can differ from airport records. The gaps are largest on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 283 m, while Niihama lies at about 13 m. Temperatures on this page were therefore adjusted by +1.8 °C3.2 °F using the standard lapse rate of 6.5 °C per 1,000 m.