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Castries vs Johannesburg
Comparing Castries change · Johannesburg change
Castries is the warmer of the two — about 16°F on the annual average; Castries is the wetter, with 46 in more rain a year, and Johannesburg the sunnier.
How the seasons compare
The differences between Castries and Johannesburg, in everyday terms.
Summers
Summers are nearly the same
Castries: Warm
Johannesburg: Warm
Winters
Castries has far milder winters
Castries: Stays warm
Johannesburg: Cool
Rain & snow
Castries is much wetter
Castries: Very wet
Johannesburg: Moderate rainfall
Sky
Johannesburg is sunnier
Castries: Fairly sunny
Johannesburg: Fairly sunny
Month-by-month charts
Temperature
Castries is the warmer of the two — about 16°F on the annual average.
Precipitation
Castries is the wetter — about 46 in more across the year.
Clear skies
Johannesburg has the clearer skies — the higher line.
Exact monthly numbers
Tap a metric to open its full table. Desktop shows all twelve months; on a phone each metric splits into Jan–Jun and Jul–Dec.
Avg high (°F) Varies through the year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Castries | 80 | 80 | 80 | 82 | 83 | 83 | 83 | 84 | 84 | 83 | 83 | 81 |
| Johannesburg | 83 | 83 | 81 | 77 | 73 | 68 | 68 | 74 | 80 | 83 | 83 | 83 |
| Difference | +3 | +3 | +1 | -5 | -10 | -15 | -15 | -10 | -4 | -1 | — | +2 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 80 | 80 | 80 | 82 | 83 | 83 |
| Johannesburg | 83 | 83 | 81 | 77 | 73 | 68 |
| Difference | +3 | +3 | +1 | -5 | -10 | -15 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 83 | 84 | 84 | 83 | 83 | 81 |
| Johannesburg | 68 | 74 | 80 | 83 | 83 | 83 |
| Difference | -15 | -10 | -4 | -1 | — | +2 |
Avg low (°F) Castries runs higher most of the year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Castries | 78 | 77 | 78 | 79 | 80 | 81 | 81 | 82 | 82 | 82 | 81 | 79 |
| Johannesburg | 61 | 61 | 58 | 53 | 47 | 42 | 40 | 45 | 52 | 56 | 58 | 60 |
| Difference | -17 | -17 | -19 | -26 | -34 | -39 | -41 | -36 | -30 | -26 | -23 | -19 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 78 | 77 | 78 | 79 | 80 | 81 |
| Johannesburg | 61 | 61 | 58 | 53 | 47 | 42 |
| Difference | -17 | -17 | -19 | -26 | -34 | -39 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 81 | 82 | 82 | 82 | 81 | 79 |
| Johannesburg | 40 | 45 | 52 | 56 | 58 | 60 |
| Difference | -41 | -36 | -30 | -26 | -23 | -19 |
Precipitation (in) Castries runs higher most of the year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Castries | 4.5 | 3 | 2.6 | 3.5 | 4.5 | 5.3 | 8.5 | 11.5 | 8.8 | 9.7 | 9.6 | 5.9 |
| Johannesburg | 5.3 | 4.9 | 4.1 | 1.9 | 0.3 | 0.1 | 0.2 | 0.1 | 0.6 | 3 | 5.7 | 4.8 |
| Difference | +0.8 | +2 | +1.5 | -1.7 | -4.2 | -5.2 | -8.4 | -11.4 | -8.2 | -6.7 | -3.9 | -1.1 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 4.5 | 3 | 2.6 | 3.5 | 4.5 | 5.3 |
| Johannesburg | 5.3 | 4.9 | 4.1 | 1.9 | 0.3 | 0.1 |
| Difference | +0.8 | +2 | +1.5 | -1.7 | -4.2 | -5.2 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 8.5 | 11.5 | 8.8 | 9.7 | 9.6 | 5.9 |
| Johannesburg | 0.2 | 0.1 | 0.6 | 3 | 5.7 | 4.8 |
| Difference | -8.4 | -11.4 | -8.2 | -6.7 | -3.9 | -1.1 |
Cloud cover (%) Varies through the year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Castries | 38 | 39 | 42 | 49 | 52 | 59 | 50 | 46 | 51 | 51 | 46 | 41 |
| Johannesburg | 61 | 57 | 50 | 40 | 25 | 20 | 18 | 21 | 29 | 47 | 58 | 65 |
| Difference | +22 | +18 | +8 | -9 | -27 | -39 | -32 | -25 | -22 | -4 | +12 | +24 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 38 | 39 | 42 | 49 | 52 | 59 |
| Johannesburg | 61 | 57 | 50 | 40 | 25 | 20 |
| Difference | +22 | +18 | +8 | -9 | -27 | -39 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 50 | 46 | 51 | 51 | 46 | 41 |
| Johannesburg | 18 | 21 | 29 | 47 | 58 | 65 |
| Difference | -32 | -25 | -22 | -4 | +12 | +24 |
Relative humidity (%) Castries runs higher most of the year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Castries | 76 | 75 | 75 | 76 | 77 | 79 | 79 | 79 | 79 | 79 | 79 | 77 |
| Johannesburg | 65 | 64 | 64 | 61 | 54 | 54 | 50 | 44 | 40 | 49 | 57 | 63 |
| Difference | -11 | -10 | -11 | -15 | -23 | -25 | -29 | -35 | -39 | -30 | -22 | -14 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 76 | 75 | 75 | 76 | 77 | 79 |
| Johannesburg | 65 | 64 | 64 | 61 | 54 | 54 |
| Difference | -11 | -10 | -11 | -15 | -23 | -25 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 79 | 79 | 79 | 79 | 79 | 77 |
| Johannesburg | 50 | 44 | 40 | 49 | 57 | 63 |
| Difference | -29 | -35 | -39 | -30 | -22 | -14 |
How both climates are changing
Both cities are warming. Each city has its own warming trend; see its trends page for the year-by-year detail. Castries trends → · Johannesburg trends →
Both cities' Köppen climate types are projected to hold steady through 2099 (SSP2-4.5).
Methodology & sources
Castries
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 10 years of daily observations at LE Lamentin, a weather station, about 66 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.
Johannesburg
Temperature & precipitation — 1991–2020 normals computed from 24 years of daily observations at Pretoria/irene, a weather station, about 36 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.
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