Bolu in Spring
In spring (March, April and May), Bolu sees average daytime highs around 14°C and overnight lows near 4°C, with 316 mm of precipitation over about 45 wet days across the season. It is the 3rd-warmest season and the wettest season of the year.
Over the season highs climb from about 8°C in early March to 19°C by late May. The sky is clear or mostly clear about 27% of the time across spring, and the air most often feels dry.
Spring is Bolu's 3rd-best season to visit on our travel score. For the whole year in context, see Bolu's year-round climate.
- Avg daytime high
- 14°C
- 3rd-warmest season
- Avg overnight low
- 4°C
- Precipitation
- 316 mm
- 45 wet days
- Avg wind
- 6 km/h
- Travel score
- 3.4
- 3rd-best season
- Months
- Mar · Apr · May
Temperature in Bolu in Spring
Over the season highs climb from about 8°C in early March to 19°C by late May.
A typical spring day in Bolu reaches about 14°C and drops to 4°C overnight. The warmest of the three months is May, the coolest March.
How spring really feels in Bolu
Once humidity and wind are folded in, spring brings about 0 days that feel above 32°C and 33 that feel at or below 0°C.
The story in spring is cold — wind chill drags the overnight "feels like" below the raw low.
Bolu weather by month
How the three spring months (March, April and May) 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 Spring
The sky is clear or mostly clear about 27% of the time across spring.
Chance of precipitation in Spring
Bolu gets around 316 mm of rain and snow over 45 wet days across spring. The line is the day-by-day chance of measurable precipitation.
Humidity in Spring
Most of spring feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Spring
Winds average 6 km/h across spring.
Sunrise & sunset in Spring
Daylight runs from about 11 hours in early March to 14 h 42 min by late May. The lit band spans sunrise to sunset each day.
Solar energy in Spring
Average shortwave solar energy reaching the ground each day across spring, about 5.1 kWh/m².
Is spring a good time to visit Bolu?
Our two travel scores rate spring for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
spring is a weaker month for outdoor sightseeing in Bolu.
What to pack for Bolu in Spring
From spring's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In spring, Bolu sees daytime highs around 14°C and nights near 4°C. Pack a warm layer, rain gear and sun protection. About 45 days see rain.
Sea temperature near Bolu in Spring
The nearest coast averages about 11°C across spring — 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 Spring
Clear-sky midday UV across spring averages around 6 — enough to warrant sun protection. 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 Spring
Average fine-particle pollution (PM2.5) through the year — so you can see where spring 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.