Koga climate
Koga (Japan) has a humid subtropical climate (Köppen Cfa). The average temperature over the year is 15 °C59 °F, and about 1,519 mm60 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Koga climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | 846 | −229 | 337 | 642.5 | 25 |
| Feb | 949 | −130 | 439 | 582.3 | 20 |
| Mar | 1356 | 235 | 846 | 1024.0 | 10 |
| Apr | 1966 | 745 | 1355 | 1214.7 | 0 |
| May | 2475 | 1355 | 1865 | 1365.4 | 0 |
| Jun | 2780 | 1763 | 2272 | 1616.3 | 0 |
| Jul | 3087 | 2171 | 2679 | 1576.2 | 0 |
| Aug | 3289 | 2272 | 2781 | 1425.6 | 0 |
| Sep | 2882 | 1966 | 2374 | 1987.8 | 0 |
| Oct | 2272 | 1355 | 1763 | 2198.6 | 0 |
| Nov | 1662 | 643 | 1152 | 953.7 | 0 |
| Dec | 1051 | 033 | 542 | 672.6 | 13 |
| Year | 3289 | −229 | 1559 | 1,51960 | 69 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total. Frost days are for the whole grid cell.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 75% | 49% | 2.6 | 9:57 |
| Feb | 75% | 54% | 3.3 | 10:49 |
| Mar | 74% | 59% | 4.1 | 11:52 |
| Apr | 74% | 64% | 4.8 | 13:04 |
| May | 76% | 71% | 5.2 | 14:04 |
| Jun | 79% | 82% | 4.7 | 14:36 |
| Jul | 81% | 83% | 4.5 | 14:23 |
| Aug | 79% | 74% | 4.6 | 13:31 |
| Sep | 81% | 76% | 3.7 | 12:21 |
| Oct | 81% | 69% | 3.1 | 11:12 |
| Nov | 79% | 55% | 2.6 | 10:11 |
| Dec | 77% | 48% | 2.3 | 9:42 |
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 Koga is like
The warmest month is August, with an average high of 32 °C89 °F and a low of 22 °C72 °F. The coldest is January, when highs average 8 °C46 °F and lows −2 °C29 °F. Seasons are strongly marked: the warmest month is on average 24.1 °C43.5 °F warmer than the coldest.
It is wet, with about 1,519 mm60 in of precipitation per year. The wettest three-month stretch is August–October, which brings 37% of the annual total. The wettest month is October (219 mm8.6 in), the driest is February (58 mm2.3 in).
Relative humidity ranges from 74% in March to 81% in September. The clearest skies (lowest average cloud amount, 48%) are typical of December. Average wind speed near the ground ranges from 8 km/h (5 mph) in November to 11 km/h (7 mph) in April. Daylight lasts from about 9.7 hours in December to 14.6 hours in June.
Best time to visit Koga
Based on these averages, the most comfortable months for sightseeing and outdoor activities are April and May and November: average highs of 16 °C62 °F to 24 °C75 °F with 95 mm3.7 in to 136 mm5.4 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of 8 °C46 °F.
Comfort score: months are ranked by how close they come to 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 Koga
- Winter (December–February) — highs 846 to 10 °C51 °F, lows −229 to 0 °C33 °F, about 63 mm2.5 in of precipitation a month. Pack a warm coat, layers and closed shoes and shoes with good grip, as frost is common.
- Spring (March–May) — highs 1356 to 24 °C75 °F, lows 235 to 13 °C55 °F, about 120 mm4.7 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket, an extra layer for the cooler mornings and evenings and an umbrella or light rain jacket.
- Summer (June–August) — highs 2780 to 32 °C89 °F, lows 1763 to 22 °C72 °F, about 153 mm6.0 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses and an umbrella or light rain jacket.
- Autumn (September–November) — highs 1662 to 28 °C82 °F, lows 643 to 19 °C66 °F, about 171 mm6.7 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket and an umbrella or light rain jacket.
How Koga compares
Compared with Kumagaya, about 30 km to the west, Koga has practically the same average temperature and receives a similar amount of precipitation.
Of the 111 places in Japan covered by World Climates, Koga is the 62nd warmest by annual mean temperature and the 78th wettest by annual precipitation. See all of them on the Japan climate page.
Places in other countries with the most similar temperature and rainfall pattern: Virginia Beach (United States, Cfa), Norfolk (United States, Cfa) and East Hampton (United States, Cfa).
Nearby places
- Kumagaya 30 km · 15 °C59 °F · 1,449 mm57 in
- Saitama 31 km · 15 °C59 °F · 1,449 mm57 in
- Tsukuba 38 km · 15 °C59 °F · 1,519 mm60 in
- Kawaguchi 42 km · 15 °C59 °F · 1,519 mm60 in
- Abiko 44 km · 15 °C59 °F · 1,519 mm60 in
- Utsunomiya 45 km · 13 °C56 °F · 1,474 mm58 in
- Tokyo 55 km · 16 °C60 °F · 1,694 mm67 in
- Maebashi 62 km · 14 °C57 °F · 1,469 mm58 in
Frequently asked questions
What is the warmest month in Koga?
August is the warmest month in Koga, with an average high of 32 °C (89 °F) and an average low of 22 °C (72 °F).
What is the coldest month in Koga?
January is the coldest month, with an average high of 8 °C (46 °F) and an average low of -2 °C (29 °F).
When does it rain the most in Koga?
October is the wettest month with about 219 mm (8.6 in) of precipitation; February is the driest with about 58 mm (2.3 in).
What is the best time to visit Koga?
Judging by long-term averages, the most comfortable months are April and May 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 — most of all 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.