Celje in Summer
In summer (June, July and August), Celje sees average daytime highs around 25°C and overnight lows near 15°C, with 310 mm of rain over about 39 wet days across the season. It is the warmest season of the year and the wettest season of the year.
Across summer, daytime highs hold fairly steady around 25°C. The sky is clear or mostly clear about 35% of the time across summer, and the air most often feels comfortable.
Summer is Celje's best season of the year to visit on our travel score. For the whole year in context, see Celje's year-round climate.
- Avg daytime high
- 25°C
- warmest season of the year
- Avg overnight low
- 15°C
- Rainfall
- 310 mm
- 39 wet days
- Avg wind
- 6 km/h
- Travel score
- 6.4
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Celje in Summer
Across summer, daytime highs hold fairly steady around 25°C.
A typical summer day in Celje reaches about 25°C and drops to 15°C overnight. The warmest of the three months is July, the coolest June.
How summer really feels in Celje
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.
Celje 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° / -3° | 41 | 7.2 | 4.3 | 8.8 | 0.0 |
| Feb | 6° / -2° | 53 | 7.4 | 4.3 | 10 | 0.4 |
| Mar | 11° / 1° | 63 | 9.9 | 3.2 | 11.6 | 2.6 |
| Apr | 15° / 6° | 76 | 11.4 | 0.8 | 13.3 | 4.4 |
| May | 20° / 10° | 95 | 13 | 0 | 14.7 | 5.8 |
| Jun | 23° / 14° | 104 | 14 | 0 | 15.5 | 6.3 |
| Jul | 25° / 15° | 105 | 13.3 | 0 | 15.2 | 6.4 |
| Aug | 25° / 15° | 101 | 12.1 | 0 | 14 | 6.6 |
| Sep | 20° / 11° | 103 | 11.2 | 0 | 12.3 | 6.1 |
| Oct | 15° / 7° | 88 | 9.1 | 0.3 | 10.7 | 4.5 |
| Nov | 9° / 3° | 86 | 9.8 | 2.3 | 9.2 | 1.6 |
| Dec | 4° / -2° | 66 | 8.9 | 4.5 | 8.5 | 0.0 |
Cloud cover in Summer
The sky is clear or mostly clear about 35% of the time across summer.
Chance of precipitation in Summer
Celje gets around 310 mm of rain over 39 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 15 h 18 min in early June to 13 h 12 min 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 5.5 kWh/m².
Is summer a good time to visit Celje?
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 a reasonable time to visit Celje for sightseeing.
What to pack for Celje in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Celje sees daytime highs around 25°C and nights near 15°C. Pack rain gear. Worth having: light clothes and sun protection. About 39 days see rain.
UV index in Celje in Summer
Clear-sky midday UV across summer averages around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Celje peaks around July 15 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (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) | 1 | 2 | 4 | 7 | 7 | 8 | 8 | 7 | 5 | 3 | 2 | 1 |
| Level | Low | Low | Moderate | High | High | Very high | Very high | Very high | High | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Low |
| Mar | 4 | Moderate |
| Apr | 7 | High |
| May | 7 | High |
| Jun | 8 | Very high |
| Jul | 8 | Very high |
| Aug | 7 | Very high |
| Sep | 5 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Low |
| Dec | 1 | Low |
Air quality in Celje 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 Celje is worst in April — around 17 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 16 | 15 | 17 | 17 | 15 | 15 | 14 | 13 | 12 | 12 | 12 | 14 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 16 | Moderate |
| Feb | 15 | Moderate |
| Mar | 17 | Moderate |
| Apr | 17 | Moderate |
| May | 15 | Moderate |
| Jun | 15 | Moderate |
| Jul | 14 | Moderate |
| Aug | 13 | Moderate |
| Sep | 12 | Good |
| Oct | 12 | Good |
| Nov | 12 | Good |
| Dec | 14 | Moderate |
Where is Celje?
Celje sits at 46.2°N, 15.3°E, 240 m above sea level, in Slovenia. The nearest listed city is Velenje, 18 km away.
Topography around Celje
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Celje.
Within 3 km, the terrain around Celje has significant variations in elevation — a maximum elevation change of 368 m around an average of 283 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 915 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,391 m.
The land around Celje is covered by trees (42%), artificial surfaces (25%) and grassland (24%) within 3 km, trees (62%) and grassland (27%) within 16 km, and trees (70%) within 80 km.
Slovenia travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type C / F
- 230 V · 50 Hz
- Prices
- ≈ 63% of US
- price level, 2025
- GDP per capita
- $37,376
- 2025
- Happiness
- 6.9 / 10
- World Happiness, 2025
- Safe drinking water
- 100%
- of population, 2024
- Homicide rate
- 0.6
- per 100k, 2023
- Road deaths
- 5.1
- per 100k/yr, 2019
- Income group
- High
- World Bank
- 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 Celje (46.2309°, 15.2604°, elevation 240 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.