Waterloo in Summer
In summer (June, July and August), Waterloo sees average daytime highs around 27°C and overnight lows near 24°C, with 1737 mm of rain over about 89 wet days across the season. It is the coldest season of the year and the wettest season of the year.
Across summer, daytime highs hold fairly steady around 27°C. The sky is clear or mostly clear about 0% of the time across summer, and the air most often feels oppressive.
Summer is Waterloo's weakest season of the year to visit on our travel score. Waterloo has little temperature swing across the year, so its calendar seasons blur — the season framing matters less here than for a place with four distinct seasons. For the whole year in context, see Waterloo's year-round climate.
- Avg daytime high
- 27°C
- coldest season of the year
- Avg overnight low
- 24°C
- Rainfall
- 1737 mm
- 89 wet days
- Avg wind
- 10 km/h
- Travel score
- 3.3
- weakest season of the year
- Months
- Jun · Jul · Aug
Temperature in Waterloo in Summer
Across summer, daytime highs hold fairly steady around 27°C.
A typical summer day in Waterloo reaches about 27°C and drops to 24°C overnight. The warmest of the three months is June, the coolest August.
How summer really feels in Waterloo
Once humidity and wind are folded in, summer brings about 4 days that feel above 32°C and 0 that feel at or below 0°C.
The story in summer is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Waterloo 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 | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 30° / 24° | 16 | 4.1 | 11.6 | 6.2 |
| Feb | 30° / 25° | 11 | 2.2 | 11.7 | 6.0 |
| Mar | 30° / 25° | 20 | 4.7 | 11.9 | 5.6 |
| Apr | 30° / 25° | 47 | 8.4 | 12.2 | 5.0 |
| May | 29° / 25° | 216 | 25.2 | 12.4 | 3.5 |
| Jun | 28° / 24° | 426 | 29.7 | 12.5 | 3.2 |
| Jul | 27° / 24° | 606 | 29.9 | 12.4 | 3.4 |
| Aug | 26° / 24° | 705 | 29.7 | 12.3 | 3.4 |
| Sep | 27° / 24° | 501 | 29.4 | 12 | 3.3 |
| Oct | 28° / 24° | 266 | 29.6 | 11.8 | 3.3 |
| Nov | 29° / 24° | 130 | 24.8 | 11.6 | 3.7 |
| Dec | 29° / 25° | 42 | 11.1 | 11.5 | 5.5 |
Cloud cover in Summer
The sky is clear or mostly clear about 0% of the time across summer.
Chance of precipitation in Summer
Waterloo gets around 1737 mm of rain over 89 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels oppressive — 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 12 h 24 min in early June to 12 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 3.9 kWh/m².
Hazard calendar for Waterloo
In summer, Waterloo overlaps its monsoon season. The full year is below, with each hazard's peak months called out.
Waterloo's monsoon runs June–September, when most of the year's rain falls.
Waterloo sees seasonal dust haze (February–April), heaviest in February.
Is summer a good time to visit Waterloo?
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 weaker month for outdoor sightseeing in Waterloo.
What to pack for Waterloo in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Waterloo sees daytime highs around 27°C and nights near 24°C. Pack light clothes and rain gear. About 89 days see rain.
Sea temperature near Waterloo in Summer
The nearest coast averages about 27°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 25 km away) is warmest in May at about 29°C and coldest in August near 27°C.
The water stays above 20°C all year — warm enough for a swim any month.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 28 | 28 | 28 | 28 | 29 | 28 | 27 | 27 | 27 | 28 | 29 | 29 |
| Comfort | Warm | Warm | Warm | Warm | Tropical | Tropical | Warm | Warm | Warm | Warm | Tropical | Tropical |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 28 | Warm |
| Feb | 28 | Warm |
| Mar | 28 | Warm |
| Apr | 28 | Warm |
| May | 29 | Tropical |
| Jun | 28 | Tropical |
| Jul | 27 | Warm |
| Aug | 27 | Warm |
| Sep | 27 | Warm |
| Oct | 28 | Warm |
| Nov | 29 | Tropical |
| Dec | 29 | Tropical |
UV index in Waterloo in Summer
Clear-sky midday UV across summer averages around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Waterloo peaks around August 20 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 8 (very high).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 9 | 12 | 12 | 11 | 12 | 12 | 11 | 13 | 12 | 11 | 9 | 8 |
| Level | Very high | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | Very high |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 9 | Very high |
| Feb | 12 | Extreme |
| Mar | 12 | Extreme |
| Apr | 11 | Extreme |
| May | 12 | Extreme |
| Jun | 12 | Extreme |
| Jul | 11 | Extreme |
| Aug | 13 | Extreme |
| Sep | 12 | Extreme |
| Oct | 11 | Extreme |
| Nov | 9 | Very high |
| Dec | 8 | Very high |
Air quality in Waterloo 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 Waterloo is worst in April — around 217 µg/m³ PM2.5 (very unhealthy), about 19.6× the cleanest month (August, 11 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 72 | 78 | 106 | 217 | 43 | 20 | 14 | 11 | 12 | 18 | 27 | 54 |
| Level | Unhealthy | Unhealthy | Unhealthy | Very unhealthy | Poor | Moderate | Moderate | Good | Moderate | Moderate | Moderate | Poor |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 72 | Unhealthy |
| Feb | 78 | Unhealthy |
| Mar | 106 | Unhealthy |
| Apr | 217 | Very unhealthy |
| May | 43 | Poor |
| Jun | 20 | Moderate |
| Jul | 14 | Moderate |
| Aug | 11 | Good |
| Sep | 12 | Moderate |
| Oct | 18 | Moderate |
| Nov | 27 | Moderate |
| Dec | 54 | Poor |
Where is Waterloo?
Waterloo sits at 8.3°N, 13.1°W, 23 m above sea level, in Sierra Leone. The nearest listed city is Freetown, 24 km away.
Topography around Waterloo
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Waterloo.
Within 3 km, the terrain around Waterloo has significant variations in elevation — a maximum elevation change of 419 m around an average of 52 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 899 m; within 80 km, large variations in elevation — a maximum elevation change of 885 m.
The land around Waterloo is covered by artificial surfaces (46%), grassland (23%) and trees (20%) within 3 km, trees (48%) within 16 km, and water (41%) and trees (39%) within 80 km.
Sierra Leone travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type D / G
- 230 V · 50 Hz
- Prices
- ≈ 24% of US
- price level, 2025
- GDP per capita
- $846
- 2025
- Happiness
- 3.3 / 10
- World Happiness, 2025
- Safe drinking water
- 11%
- of population, 2024
- Homicide rate
- 2.2
- per 100k, 2020
- Road deaths
- 33
- per 100k/yr, 2019
- Income group
- Low
- 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 Waterloo (8.3389°, -13.0709°, elevation 23 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.