Ratnapura weather in September

In September, Ratnapura sees average daytime highs of 26°C and overnight lows near 21°C, with 246 mm of rain across 26 wet days and about 12 hours of daylight. It is the 10th-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 2% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 06 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Ratnapura's 6th-clearest and 4th-windiest month. For the whole year in context, see Ratnapura's year-round climate.

Daytime high
26°
10th warmest
Overnight low
21°
8th coldest
Rainfall
246 mm
26 wet days
Daylight
12 hours
6:02 AM – 6:04 PM
Cloud cover
83%
6th clearest
Wind
6 km/h
4th windiest
Solar energy
4.93 kWh/m²
Travel score
3.9
out of 10

Ratnapura is city in Sabaragamuwa, Sri Lanka.

Density
2,392/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 26°C through the month.

A typical September day in Ratnapura reaches about 26°C in the afternoon and slips back to 21°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 27°C. Set against its neighbours, September runs on par with August and on par with October.

20°23°25°28°30°151015202530
Avg high (°C)Avg low (°C)
12621
22621
32621
42621
52621
62621
72621
82621
92621
102621
112621
122621
132621
142621
152621
162621
172621
182621
192621
202621
212621
222621
232621
242621
252621
262621
272621
282621
292621
302621

Ratnapura weather by month

How September compares with the rest of the year at a glance. September is the 10th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan27° / 19°30822.811.74.5
Feb28° / 19°27920.511.84.6
Mar28° / 20°30927.4123.7
Apr28° / 21°4682912.13.3
May27° / 22°31029.612.33.4
Jun26° / 22°26727.912.43.6
Jul26° / 21°24628.512.33.7
Aug26° / 21°22828.312.23.7
Sep26° / 21°24626123.9
Oct27° / 21°49727.511.93.8
Nov27° / 20°66126.911.73.8
Dec27° / 20°51526.111.64.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 2% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 9% of September, with mostly cloudy or overcast conditions the remaining 89%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
11090
21090
31189
41189
51189
61189
71288
81288
91387
101387
111387
121387
131288
141288
151288
161288
171288
181288
191189
201189
211189
221090
231090
241090
251189
261189
271189
281189
291189
301189

Chance of precipitation in September

Any precipitation

Ratnapura gets around 246 mm of rain over 26 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 87% and peaks near 88% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
188
287
387
487
586
686
786
886
986
1086
1186
1286
1387
1487
1587
1687
1788
1888
1988
2088
2188
2288
2388
2488
2588
2688
2788
2888
2988
3088

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the oppressive band about 55% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)
14852
24951
34951
44951
54951
64951
74852
84852
94753
104654
114654
124555
134456
144357
154258
164159
174159
184159
194159
204159
214159
224258
234258
244357
254357
264456
274456
284555
294555
304654

Wind in September

Winds average 6 km/h in September.

Across September, daily wind ranges from about 5 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
275calm
285calm
295calm
305calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 06 min at the start of September to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over September. Sunrise moves from 6:04 AM to 5:59 AM, and sunset from 6:12 PM to 5:56 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.16:046:12
212.16:046:11
312.16:046:11
412.16:046:10
512.16:046:10
612.16:036:09
712.16:036:09
812.16:036:08
912.16:036:08
1012.16:036:07
1112.16:036:07
1212.16:026:06
1312.16:026:05
1412.06:026:05
1512.06:026:04
1612.06:026:04
1712.06:016:03
1812.06:016:03
1912.06:016:02
2012.06:016:02
2112.06:016:01
2212.06:016:00
2312.06:006:00
2412.06:005:59
2512.06:005:59
2612.06:005:58
2712.06:005:58
2812.06:005:57
2912.05:595:57
3011.95:595:56

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.93 kWh/m².

For context, solar energy here swings from a low near 4.23 kWh/m² to a high of 6.05 kWh/m² in March across the year — September's 4.93 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
15.0Bright
25.0Bright
35.0Bright
45.0Bright
55.0Bright
65.0Bright
75.0Bright
85.0Bright
95.0Bright
105.0Bright
115.0Bright
125.0Bright
135.0Bright
145.0Bright
155.0Bright
165.0Bright
174.9Bright
184.9Bright
194.9Bright
204.9Bright
214.9Bright
224.9Bright
234.9Bright
244.8Bright
254.8Bright
264.8Bright
274.8Bright
284.8Bright
294.8Bright
304.8Bright
Planning a trip in September

Hazard calendar for Ratnapura

In seasonPeak

In September, Ratnapura sits inside its cyclone season. The full year is below, with each hazard's peak months called out.

Ratnapura sits in the North Indian Ocean cyclone zone; the season peaks May and October–November.

Cyclone
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Ratnapura?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

3.9
Sightseeing
4th-best month of the year
3.8
Beach & pool
5th-best month of the year

September is a weaker month for outdoor sightseeing in Ratnapura.

What to pack for Ratnapura in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Ratnapura sees daytime highs around 26°C and nights near 21°C. Pack rain gear. Worth having: light clothes and sun protection. About 26 days see rain.

rain gearlight clothessun protection

Sea temperature near Ratnapura in September

The nearest coast averages about 28°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 59 km away) is warmest in April at about 30°C and coldest in August near 28°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan28Warm
Feb28Tropical
Mar29Tropical
Apr30Tropical
May29Tropical
Jun28Tropical
Jul28Warm
Aug28Warm
Sep28Warm
Oct28Tropical
Nov29Tropical
Dec28Tropical

UV index in Ratnapura in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Ratnapura peaks around April 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 10 (extreme).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeApr 17UV 14Dec 17UV 10
UV index (midday)Level
Jan11Extreme
Feb14Extreme
Mar13Extreme
Apr14Extreme
May13Extreme
Jun11Extreme
Jul12Extreme
Aug13Extreme
Sep13Extreme
Oct13Extreme
Nov11Extreme
Dec10Extreme

Air quality in Ratnapura in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Ratnapura is worst in January — around 84 µg/m³ PM2.5 (unhealthy), about 2.8× the cleanest month (July, 29 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0306090JanFebMarAprMayJunJulAugSepOctNovDecUnhealthyPoorModeratePoorUnhealthyJan 1483 µg/m³Jul 2129 µg/m³
PM2.5 (µg/m³)Level
Jan84Unhealthy
Feb78Unhealthy
Mar73Unhealthy
Apr62Unhealthy
May44Poor
Jun31Moderate
Jul29Moderate
Aug30Moderate
Sep35Poor
Oct52Poor
Nov74Unhealthy
Dec81Unhealthy
Location & terrain

Where is Ratnapura?

Ratnapura sits at 6.7°N, 80.4°E, 73 m above sea level, in Sri Lanka. The nearest listed city is Hatton, 31 km away.

HattonHanwella IhalaHomagamaKalutaraBeruwalaNuwara EliyaBentotaPanadura

Topography around Ratnapura

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Ratnapura.

Within 3 km, the terrain around Ratnapura has significant variations in elevation — a maximum elevation change of 364 m around an average of 79 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,947 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,500 m.

The land around Ratnapura is covered by trees (93%) within 3 km, trees (98%) within 16 km, and trees (79%) within 80 km.

3 km
364 m
16 km
1,947 m
80 km
2,500 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Hatton 31 km · Hanwella Ihala 43 km · Homagama 48 km · Kalutara 50 km · Beruwala 52 km · Nuwara Eliya 53 km · Bentota 54 km · Panadura 55 km

Sri Lanka travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type D / G / M
230 V · 50 Hz
Prices
≈ 27% of US
price level, 2025
GDP per capita
$5,002
2025
Happiness
4.0 / 10
World Happiness, 2025
Safe drinking water
47%
of population, 2024
Homicide rate
3.3
per 100k, 2019
Road deaths
19.7
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 486
Religion
Buddhist 70%Hindu 13%Muslim 10%Roman Catholic 6%

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 Ratnapura (6.6858°, 80.4036°, elevation 73 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).