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Ratnapura, Sri Lanka climate
Af Tropical rainforest
Ratnapura has a remarkably steady tropical climate (Tropical rainforest, Köppen Af). The hottest month is April with an average daily high near 32°C, while the coldest is January averaging around 24°C at night. Precipitation totals about 2385 mm a year and is strongly seasonal — November alone averages 340 mm while January barely receives 65 mm.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresClear vs cloudy days
Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day countsRatnapura climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 31 | 32 | 32 | 32 | 32 | 30 | 30 | 30 | 30 | 30 | 31 | 31 |
| Avg temp (°C) | 28 | 28 | 29 | 30 | 30 | 29 | 29 | 28 | 28 | 28 | 28 | 28 |
| Avg low (°C) | 24 | 25 | 26 | 27 | 28 | 27 | 27 | 26 | 27 | 26 | 26 | 25 |
| Precipitation (mm) | 65 | 85 | 104 | 270 | 312 | 178 | 96 | 115 | 276 | 289 | 340 | 256 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 31 | 32 | 32 | 32 | 32 | 30 |
| Avg temp (°C) | 28 | 28 | 29 | 30 | 30 | 29 |
| Avg low (°C) | 24 | 25 | 26 | 27 | 28 | 27 |
| Precipitation (mm) | 65 | 85 | 104 | 270 | 312 | 178 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 30 | 30 | 30 | 30 | 31 | 31 |
| Avg temp (°C) | 29 | 28 | 28 | 28 | 28 | 28 |
| Avg low (°C) | 27 | 26 | 27 | 26 | 26 | 25 |
| Precipitation (mm) | 96 | 115 | 276 | 289 | 340 | 256 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 3 | 4 | 6 | 9 | 12 | 11 | 7 | 8 | 11 | 12 | 11 | 8 |
| Days with high ≥ 32°C (days) | 5 | 6 | 7 | 11 | 7 | 0.5 | 0.1 | 0.3 | — | 0.2 | 2 | 3 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 3 | 4 | 6 | 9 | 12 | 11 |
| Days with high ≥ 32°C (days) | 5 | 6 | 7 | 11 | 7 | 0.5 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 7 | 8 | 11 | 12 | 11 | 8 |
| Days with high ≥ 32°C (days) | 0.1 | 0.3 | — | 0.2 | 2 | 3 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 59 | 53 | 53 | 65 | 73 | 77 | 77 | 74 | 73 | 76 | 78 | 70 |
| Clear days (≤ 30% cloud) | 7 | 7 | 7 | 4 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 4 |
| Partly cloudy days (30–70%) | 10 | 12 | 15 | 11 | 9 | 8 | 9 | 10 | 9 | 9 | 8 | 10 |
| Cloudy days (≥ 70%) | 13 | 9 | 9 | 15 | 19 | 21 | 21 | 20 | 19 | 20 | 20 | 18 |
| Relative humidity (%) | 79 | 75 | 73 | 80 | 85 | 86 | 86 | 86 | 85 | 85 | 84 | 82 |
| Wind speed (m/s) | 3.5 | 2.7 | 2.1 | 2.4 | 4.0 | 4.5 | 4.4 | 4.3 | 4.1 | 3.3 | 2.8 | 3.4 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 59 | 53 | 53 | 65 | 73 | 77 |
| Clear days (≤ 30% cloud) | 7 | 7 | 7 | 4 | 3 | 2 |
| Partly cloudy days (30–70%) | 10 | 12 | 15 | 11 | 9 | 8 |
| Cloudy days (≥ 70%) | 13 | 9 | 9 | 15 | 19 | 21 |
| Relative humidity (%) | 79 | 75 | 73 | 80 | 85 | 86 |
| Wind speed (m/s) | 3.5 | 2.7 | 2.1 | 2.4 | 4.0 | 4.5 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 77 | 74 | 73 | 76 | 78 | 70 |
| Clear days (≤ 30% cloud) | 2 | 2 | 2 | 2 | 2 | 4 |
| Partly cloudy days (30–70%) | 9 | 10 | 9 | 9 | 8 | 10 |
| Cloudy days (≥ 70%) | 21 | 20 | 19 | 20 | 20 | 18 |
| Relative humidity (%) | 86 | 86 | 85 | 85 | 84 | 82 |
| Wind speed (m/s) | 4.4 | 4.3 | 4.1 | 3.3 | 2.8 | 3.4 |
Methodology & sources
Temperature — modelled for this location from ERA5-Land reanalysis, a ~9 km global grid, because no long-record weather station is close enough to use.
Precipitation — 1991–2020 normals computed from 12 years of daily observations at Colombo, a weather station, about 64 km from the city centre. The underlying daily records come from NOAA's global station network.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.