Bolu in Summer
In summer (June, July and August), Bolu sees average daytime highs around 23°C and overnight lows near 13°C, with 198 mm of rain over about 30 wet days across the season. It is the warmest season of the year and the driest season of the year.
Over the season highs climb from about 20°C in early June to 24°C by late August. The sky is clear or mostly clear about 56% of the time across summer, and the air most often feels comfortable.
Summer is Bolu's best season of the year to visit on our travel score. For the whole year in context, see Bolu's year-round climate.
- Avg daytime high
- 23°C
- warmest season of the year
- Avg overnight low
- 13°C
- Rainfall
- 198 mm
- 30 wet days
- Avg wind
- 6 km/h
- Travel score
- 7.2
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Bolu in Summer
Over the season highs climb from about 20°C in early June to 24°C by late August.
A typical summer day in Bolu reaches about 23°C and drops to 13°C overnight. The warmest of the three months is August, the coolest June.
How summer really feels in Bolu
Once humidity and wind are folded in, summer brings about 0 days that feel above 32°C and 0 that feel at or below 0°C.
summer sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Bolu weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 4° / -4° | 91 | 13.9 | 11 | 9.4 | 0.0 |
| Feb | 5° / -3° | 88 | 13.8 | 10 | 10.4 | 0.2 |
| Mar | 9° / -0° | 107 | 14.9 | 8.5 | 11.7 | 1.6 |
| Apr | 14° / 4° | 99 | 14.4 | 2.5 | 13.1 | 3.5 |
| May | 18° / 8° | 110 | 15.9 | 0.1 | 14.2 | 5.2 |
| Jun | 22° / 11° | 96 | 13.3 | 0 | 14.9 | 6.3 |
| Jul | 24° / 14° | 50 | 8.6 | 0 | 14.6 | 7.6 |
| Aug | 25° / 14° | 52 | 8.3 | 0 | 13.6 | 7.7 |
| Sep | 22° / 11° | 66 | 8.8 | 0 | 12.3 | 7.1 |
| Oct | 17° / 7° | 90 | 11.2 | 0.8 | 10.9 | 5.4 |
| Nov | 11° / 2° | 75 | 10.3 | 3.6 | 9.7 | 2.8 |
| Dec | 6° / -2° | 96 | 13.4 | 8.2 | 9.1 | 0.4 |
Cloud cover in Summer
The sky is clear or mostly clear about 56% of the time across summer.
Chance of precipitation in Summer
Bolu gets around 198 mm of rain over 30 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels comfortable — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 6 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 42 min in early June to 13 hours by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 6.6 kWh/m².
Is summer a good time to visit Bolu?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is one of the better times to visit Bolu for general sightseeing.
What to pack for Bolu in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Bolu sees daytime highs around 23°C and nights near 13°C. Pack sun protection. Worth having: light clothes and rain gear. About 30 days see rain.
Sea temperature near Bolu in Summer
The nearest coast averages about 23°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 47 km away) is warmest in August at about 25°C and coldest in February near 7°C.
It's comfortable for a long swim from Jun 11 to Oct 12 — about 4.1 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 9 | 7 | 8 | 11 | 16 | 21 | 24 | 25 | 23 | 20 | 15 | 12 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Refreshing | Warm | Refreshing | Cool | Cool | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 9 | Bracing |
| Feb | 7 | Bracing |
| Mar | 8 | Bracing |
| Apr | 11 | Bracing |
| May | 16 | Cool |
| Jun | 21 | Refreshing |
| Jul | 24 | Refreshing |
| Aug | 25 | Warm |
| Sep | 23 | Refreshing |
| Oct | 20 | Cool |
| Nov | 15 | Cool |
| Dec | 12 | Bracing |
UV index in Bolu in Summer
Clear-sky midday UV across summer averages around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Bolu peaks around August 10 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 2 | 3 | 7 | 7 | 9 | 9 | 9 | 6 | 4 | 2 | 2 |
| Level | Low | Moderate | Moderate | High | Very high | Very high | Very high | Very high | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 2 | Moderate |
| Mar | 3 | Moderate |
| Apr | 7 | High |
| May | 7 | Very high |
| Jun | 9 | Very high |
| Jul | 9 | Very high |
| Aug | 9 | Very high |
| Sep | 6 | High |
| Oct | 4 | Moderate |
| Nov | 2 | Moderate |
| Dec | 2 | Low |
Air quality in Bolu in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer falls, not just the annual average.
Air quality in Bolu is worst in May — around 33 µg/m³ PM2.5 (moderate), about 1.7× the cleanest month (December, 19 µg/m³).
Seasonal pattern from CAMS reanalysis, scaled to Bolu's WHO annual average of 24.4 µg/m³.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 20 | 23 | 32 | 33 | 33 | 26 | 21 | 21 | 20 | 22 | 22 | 19 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 20 | Moderate |
| Feb | 23 | Moderate |
| Mar | 32 | Moderate |
| Apr | 33 | Moderate |
| May | 33 | Moderate |
| Jun | 26 | Moderate |
| Jul | 21 | Moderate |
| Aug | 21 | Moderate |
| Sep | 20 | Moderate |
| Oct | 22 | Moderate |
| Nov | 22 | Moderate |
| Dec | 19 | Moderate |
Where is Bolu?
Bolu sits at 40.7°N, 31.6°E, 733 m above sea level, in Turkey. The nearest listed city is Kaynaşlı, 24 km away.
Topography around Bolu
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Bolu.
Within 3 km, the terrain around Bolu has only modest variations in elevation — a maximum elevation change of 178 m around an average of 745 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,296 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,359 m.
The land around Bolu is covered by artificial surfaces (51%) and cropland (33%) within 3 km, trees (67%) within 16 km, and trees (63%) and grassland (21%) within 80 km.
Turkey travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type C / F
- 230 V · 50 Hz
- Prices
- ≈ 41% of US
- price level, 2025
- GDP per capita
- $18,599
- 2025
- Happiness
- 5.3 / 10
- World Happiness, 2025
- Homicide rate
- 3.2
- per 100k, 2023
- Road deaths
- 6.7
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Low
- EF EPI 488
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Bolu (40.7358°, 31.6061°, elevation 733 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.