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Bolu, Bolu Weather by Month and Climate Averages
Monthly normals · Rain · Snow
Sunshine · Freeze dates · Records · Best time to visit
What is the weather like in Bolu, Bolu?
Bolu, Bolu gets 539 mm of precipitation a year over about 118 rainy days. August is the warmest month (average high 29°C) and January the coldest (average low -3°C).
Oceanic climate
Bolu, Bolu has warm summers and chilly winters. Daytime highs range from about 6°C in January to 29°C in August. June is usually the wettest month. The most comfortable time to visit is typically April to May and September to October, when daytime highs sit near 21°C.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Dec–Feb | -2° | 7° |
| Spring | Mar–May | 4° | 17° |
| Summer | Jun–Aug | 13° | 27° |
| Autumn | Sep–Nov | 7° | 19° |
How much rain does Bolu get?
Bolu gets 539 mm of precipitation in an average year, spread over about 118 days with measurable rain.
June is the wettest month, with 64 mm. August is the driest, with 20 mm. March has the most rainy days, about 14.
The longest dry spell in the last five years lasted 28 days, to November 17, 2022.
From October 2025 to September 2026 Bolu got 478 mm of rain, against a normal of 539 mm for those months. September 2026 had the most, with 198 mm.
Bolu weather by month
Bolu weather in January
In January, Bolu averages a high of 6°C and a low of -3°C. It gets 53 mm of precipitation over about 14 rainy days. Estimated sunshine is 34% of daylight hours, derived from ERA5 cloud cover. The January record high is 20°C (1987) and the record low is -22°C (1974).
Bolu weather in February
In February, Bolu averages a high of 8°C and a low of -2°C. It gets 48 mm of precipitation over about 13 rainy days. Estimated sunshine is 34% of daylight hours, derived from ERA5 cloud cover. The February record high is 22°C (2024) and the record low is -22°C (1985).
Bolu weather in March
In March, Bolu averages a high of 12°C and a low of 1°C. It gets 57 mm of precipitation over about 14 rainy days. Estimated sunshine is 30% of daylight hours, derived from ERA5 cloud cover. The March record high is 28°C (2001) and the record low is -18°C (1985).
Bolu weather in April
In April, Bolu averages a high of 17°C and a low of 4°C. It gets 47 mm of precipitation over about 11 rainy days. Estimated sunshine is 36% of daylight hours, derived from ERA5 cloud cover. The April record high is 32°C (1998) and the record low is -10°C (1997). April is one of the most comfortable months to visit.
Bolu weather in May
In May, Bolu averages a high of 22°C and a low of 8°C. It gets 56 mm of precipitation over about 11 rainy days. Estimated sunshine is 40% of daylight hours, derived from ERA5 cloud cover. The May record high is 33°C (2007) and the record low is -5°C (1985). May is one of the most comfortable months to visit.
Bolu weather in June
In June, Bolu averages a high of 26°C and a low of 12°C. It gets 64 mm of precipitation over about 10 rainy days. Estimated sunshine is 43% of daylight hours, derived from ERA5 cloud cover. The June record high is 37°C (1996) and the record low is 1°C (1987).
Bolu weather in July
In July, Bolu averages a high of 28°C and a low of 14°C. It gets 34 mm of precipitation over about 5 rainy days. Estimated sunshine is 61% of daylight hours, derived from ERA5 cloud cover. The July record high is 39°C (2000) and the record low is 3°C (1995).
Bolu weather in August
In August, Bolu averages a high of 29°C and a low of 14°C. It gets 20 mm of precipitation over about 4 rainy days. Estimated sunshine is 66% of daylight hours, derived from ERA5 cloud cover. The August record high is 43°C (2023) and the record low is 5°C (1982).
Bolu weather in September
In September, Bolu averages a high of 25°C and a low of 11°C. It gets 24 mm of precipitation over about 6 rainy days. Estimated sunshine is 50% of daylight hours, derived from ERA5 cloud cover. The September record high is 38°C (2020) and the record low is 1°C (1987). September is one of the most comfortable months to visit.
Bolu weather in October
In October, Bolu averages a high of 20°C and a low of 7°C. It gets 45 mm of precipitation over about 9 rainy days. Estimated sunshine is 48% of daylight hours, derived from ERA5 cloud cover. The October record high is 34°C (2012) and the record low is -6°C (1973). October is one of the most comfortable months to visit.
Bolu weather in November
In November, Bolu averages a high of 13°C and a low of 2°C. It gets 39 mm of precipitation over about 9 rainy days. Estimated sunshine is 40% of daylight hours, derived from ERA5 cloud cover. The November record high is 27°C (2023) and the record low is -15°C (1973).
Bolu weather in December
In December, Bolu averages a high of 8°C and a low of -1°C. It gets 53 mm of precipitation over about 13 rainy days. Estimated sunshine is 38% of daylight hours, derived from ERA5 cloud cover. The December record high is 23°C (2010) and the record low is -23°C (1992).
Sunshine, humidity and wind in Bolu
August is the sunniest month in Bolu, with estimated sunshine of 66% of daylight hours from ERA5 cloud cover. March is the cloudiest, at 30%. The annual cloud-cover estimate is 43% of daylight hours; it is not a measurement of sunshine duration. Bolu is cloudier than 91% of Turkey.
Humidity peaks in December at 84% and is lowest in August at 70%.
Bolu has about 11 days a year above 32°C. Bolu is cooler than 77% of Turkey.
First and last freeze in Bolu
The first fall freeze in Bolu typically comes around November 1, and the last spring freeze around April 22. That leaves a frost-free growing season of about 193 days.
Bolu weather records
These records cover BOLU during 1973–2026. Earlier records or other stations in the city may differ.
The hottest temperature on record at the Bolu station is 43°C, on August 15, 2023. The coldest is -23°C, on December 31, 1992.
The wettest day in the available station history brought 107 mm of precipitation, on August 15, 1983.
24 all-time records have been set at the station since 1973.
The best time to visit Bolu
The most comfortable time to visit is typically April to May and September to October, when daytime highs sit near 21°C.
Winter (December–February) is chilly, with average highs around 7°C and lows near -2°C.
Spring (March–May) is mild, with average highs around 17°C and lows near 4°C.
Summer (June–August) is warm, with average highs around 27°C and lows near 13°C. It can feel humid.
Autumn (September–November) is mild, with average highs around 20°C and lows near 6°C.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|
| January | -3° | 6° | 53 mm | 14 | 82% | 34% | 20° | -22° |
| February | -2° | 8° | 48 mm | 13 | 77% | 34% | 22° | -22° |
| March | 1° | 12° | 57 mm | 14 | 77% | 30% | 28° | -18° |
| April | 4° | 17° | 47 mm | 11 | 72% | 36% | 32° | -10° |
| May | 8° | 22° | 56 mm | 11 | 76% | 40% | 33° | -5° |
| June | 12° | 26° | 64 mm | 10 | 80% | 43% | 37° | 1° |
| July | 14° | 28° | 34 mm | 5 | 76% | 61% | 39° | 3° |
| August | 14° | 29° | 20 mm | 4 | 70% | 66% | 43° | 5° |
| September | 11° | 25° | 24 mm | 6 | 73% | 50% | 38° | 1° |
| October | 7° | 20° | 45 mm | 9 | 76% | 48% | 34° | -6° |
| November | 2° | 13° | 39 mm | 9 | 80% | 40% | 27° | -15° |
| December | -1° | 8° | 53 mm | 13 | 84% | 38% | 23° | -23° |
Station: BOLU, 1 km from the city. Temperature normal baseline: 1991–2020, calculated from available NOAA GHCN-Daily observations. Available station history: 1973–2026; record values refer to this station and period, not the entire city’s history. Precipitation includes rain and the water equivalent of frozen precipitation; snowfall depth is shown separately when available. Sources and methods
From ERA5 reanalysis. Sunshine is estimated from cloud cover.
Bolu climate questions
How much rain does Bolu get?
Bolu gets 539 mm of precipitation in an average year, over about 118 rainy days.
What is the wettest month in Bolu?
June is the wettest month in Bolu, with 64 mm. August is the driest, with 20 mm.
How many rainy days does Bolu have a year?
Bolu has about 118 days with measurable rain in an average year. March has the most, about 14.
What is the hottest month in Bolu?
August is the warmest month in Bolu, with an average high of 29°C.
What is the coldest month in Bolu?
January is the coldest month in Bolu, with an average low of -3°C.
What is the record high temperature in Bolu?
Within the available 1973–2026 station history, the record high at the Bolu station is 43°C, set on August 15, 2023. The record low is -23°C, on December 31, 1992.
What is the sunniest month in Bolu?
August is the sunniest month in Bolu, with estimated sunshine of 66% of daylight hours from ERA5 cloud cover. March is the cloudiest.
When is the first frost in Bolu?
The first fall freeze in Bolu typically comes around November 1. The last spring freeze is around April 22.
What is the best time to visit Bolu?
The most comfortable time to visit is typically April to May and September to October, when daytime highs sit near 21°C.