Hennef (Sieg) in Summer
In summer (June, July and August), Hennef (Sieg) sees average daytime highs around 22°C and overnight lows near 13°C, with 230 mm of rain over about 37 wet days across the season. It is the warmest season of the year and the 2nd-wettest season.
Across summer, daytime highs hold fairly steady around 22°C. The sky is clear or mostly clear about 19% of the time across summer, and the air most often feels dry.
Summer is Hennef (Sieg)'s best season of the year to visit on our travel score. For the whole year in context, see Hennef (Sieg)'s year-round climate.
- Avg daytime high
- 22°C
- warmest season of the year
- Avg overnight low
- 13°C
- Rainfall
- 230 mm
- 37 wet days
- Avg wind
- 10 km/h
- Travel score
- 6.3
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Hennef (Sieg) in Summer
Across summer, daytime highs hold fairly steady around 22°C.
A typical summer day in Hennef (Sieg) reaches about 22°C and drops to 13°C overnight. The warmest of the three months is July, the coolest June.
How summer really feels in Hennef (Sieg)
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.
Hennef (Sieg) 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 | 5° / 1° | 77 | 14 | 2.8 | 8.2 | 0.0 |
| Feb | 6° / 1° | 64 | 12 | 3.7 | 9.7 | 0.3 |
| Mar | 10° / 3° | 68 | 13.6 | 1.6 | 11.5 | 2.0 |
| Apr | 14° / 6° | 53 | 10.9 | 0.3 | 13.5 | 4.0 |
| May | 18° / 9° | 64 | 11.9 | 0 | 15.2 | 5.5 |
| Jun | 21° / 12° | 73 | 11.8 | 0 | 16.2 | 6.0 |
| Jul | 23° / 14° | 77 | 13 | 0 | 15.8 | 6.4 |
| Aug | 23° / 14° | 81 | 12.3 | 0 | 14.3 | 6.4 |
| Sep | 19° / 11° | 68 | 11 | 0 | 12.4 | 5.7 |
| Oct | 14° / 8° | 74 | 12.2 | 0 | 10.4 | 3.7 |
| Nov | 9° / 4° | 76 | 13.5 | 1 | 8.7 | 1.4 |
| Dec | 5° / 2° | 91 | 15.5 | 3.5 | 7.8 | 0.2 |
Cloud cover in Summer
The sky is clear or mostly clear about 19% of the time across summer.
Chance of precipitation in Summer
Hennef (Sieg) gets around 230 mm of rain over 37 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 10 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 15 h 54 min in early June to 13 h 24 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 5.0 kWh/m².
Is summer a good time to visit Hennef (Sieg)?
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 Hennef (Sieg) for sightseeing.
What to pack for Hennef (Sieg) in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Hennef (Sieg) sees daytime highs around 22°C and nights near 13°C. Worth packing: light clothes, rain gear and sun protection. About 37 days see rain.
UV index in Hennef (Sieg) in Summer
Clear-sky midday UV across summer 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 Hennef (Sieg) peaks around July 14 at about 7 (high) — sunscreen and a hat are worth it in the middle of the day. 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 7 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 1 | 3 | 4 | 6 | 6 | 7 | 6 | 4 | 2 | 1 | 1 |
| Level | Low | Low | Moderate | Moderate | High | High | High | High | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 1 | Low |
| Mar | 3 | Moderate |
| Apr | 4 | Moderate |
| May | 6 | High |
| Jun | 6 | High |
| Jul | 7 | High |
| Aug | 6 | High |
| Sep | 4 | Moderate |
| Oct | 2 | Moderate |
| Nov | 1 | Low |
| Dec | 1 | Low |
Where is Hennef (Sieg)?
Hennef (Sieg) sits at 50.8°N, 7.3°E, 68 m above sea level, in Germany. The nearest listed city is Siegburg, 6.0 km away.
Topography around Hennef (Sieg)
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Hennef (Sieg).
Within 3 km, the terrain around Hennef (Sieg) has only modest variations in elevation — a maximum elevation change of 151 m around an average of 112 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 413 m; within 80 km, large variations in elevation — a maximum elevation change of 1,054 m.
The land around Hennef (Sieg) is covered by trees (46%) and grassland (21%) within 3 km, trees (53%) and grassland (26%) within 16 km, and trees (55%) within 80 km.
Germany travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type C / F
- 230 V · 50 Hz
- Prices
- ≈ 80% of US
- price level, 2025
- GDP per capita
- $60,496
- 2025
- Happiness
- 6.9 / 10
- World Happiness, 2025
- Safe drinking water
- 100%
- of population, 2024
- Homicide rate
- 0.9
- per 100k, 2023
- Road deaths
- 3.8
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Very high
- EF EPI 615
- 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 Hennef (Sieg) (50.7756°, 7.2831°, elevation 68 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.