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Castries vs Boulder
Comparing Castries change · Boulder change
Castries is the warmer of the two — about 30°F on the annual average; Castries is the wetter, with 63 in more rain a year.
How the seasons compare
The differences between Castries and Boulder, in everyday terms.
Summers
Boulder has hotter summers
Castries: Warm
Boulder: Hot
Winters
Castries has far milder winters
Castries: Stays warm
Boulder: Very cold
Rain & snow
Castries is much wetter
Castries: Very wet
Boulder: Fairly dry
Sky
Similar amounts of sun
Castries: Fairly sunny
Boulder: Partly cloudy
Month-by-month charts
Temperature
Castries is the warmer of the two — about 30°F on the annual average.
Precipitation
Castries is the wetter — about 63 in more across the year.
Clear skies
The two cities see a similar amount of sun.
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) Castries runs higher most of 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 |
| Boulder | 44 | 46 | 56 | 63 | 72 | 84 | 90 | 88 | 80 | 66 | 53 | 44 |
| Difference | -36 | -34 | -25 | -19 | -11 | +1 | +7 | +4 | -4 | -18 | -29 | -37 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 80 | 80 | 80 | 82 | 83 | 83 |
| Boulder | 44 | 46 | 56 | 63 | 72 | 84 |
| Difference | -36 | -34 | -25 | -19 | -11 | +1 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 83 | 84 | 84 | 83 | 83 | 81 |
| Boulder | 90 | 88 | 80 | 66 | 53 | 44 |
| Difference | +7 | +4 | -4 | -18 | -29 | -37 |
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 |
| Boulder | 16 | 19 | 27 | 34 | 43 | 52 | 58 | 56 | 47 | 35 | 25 | 16 |
| Difference | -62 | -59 | -51 | -45 | -37 | -28 | -23 | -25 | -35 | -47 | -56 | -63 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 78 | 77 | 78 | 79 | 80 | 81 |
| Boulder | 16 | 19 | 27 | 34 | 43 | 52 |
| Difference | -62 | -59 | -51 | -45 | -37 | -28 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 81 | 82 | 82 | 82 | 81 | 79 |
| Boulder | 58 | 56 | 47 | 35 | 25 | 16 |
| Difference | -23 | -25 | -35 | -47 | -56 | -63 |
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 |
| Boulder | 0.4 | 0.4 | 1 | 1.8 | 2.4 | 1.4 | 1.7 | 1.8 | 1.2 | 1 | 0.7 | 0.4 |
| Difference | -4 | -2.6 | -1.6 | -1.8 | -2.1 | -3.9 | -6.8 | -9.7 | -7.6 | -8.7 | -8.9 | -5.5 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 4.5 | 3 | 2.6 | 3.5 | 4.5 | 5.3 |
| Boulder | 0.4 | 0.4 | 1 | 1.8 | 2.4 | 1.4 |
| Difference | -4 | -2.6 | -1.6 | -1.8 | -2.1 | -3.9 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 8.5 | 11.5 | 8.8 | 9.7 | 9.6 | 5.9 |
| Boulder | 1.7 | 1.8 | 1.2 | 1 | 0.7 | 0.4 |
| Difference | -6.8 | -9.7 | -7.6 | -8.7 | -8.9 | -5.5 |
Snowfall (in)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Castries | — | — | — | — | — | — | — | — | — | — | — | — |
| Boulder | 5.2 | 5.3 | 6 | 3.1 | 0.5 | 0 | 0 | 0 | 0.2 | 3.2 | 5.8 | 5.2 |
| Difference | — | — | — | — | — | — | — | — | — | — | — | — |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | — | — | — | — | — | — |
| Boulder | 5.2 | 5.3 | 6 | 3.1 | 0.5 | 0 |
| Difference | — | — | — | — | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | — | — | — | — | — | — |
| Boulder | 0 | 0 | 0.2 | 3.2 | 5.8 | 5.2 |
| Difference | — | — | — | — | — | — |
Cloud cover (%) Boulder runs higher most of 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 |
| Boulder | 57 | 57 | 56 | 59 | 58 | 49 | 50 | 50 | 43 | 46 | 51 | 55 |
| Difference | +19 | +18 | +14 | +10 | +6 | -10 | — | +4 | -8 | -5 | +5 | +15 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 38 | 39 | 42 | 49 | 52 | 59 |
| Boulder | 57 | 57 | 56 | 59 | 58 | 49 |
| Difference | +19 | +18 | +14 | +10 | +6 | -10 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 50 | 46 | 51 | 51 | 46 | 41 |
| Boulder | 50 | 50 | 43 | 46 | 51 | 55 |
| Difference | — | +4 | -8 | -5 | +5 | +15 |
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 |
| Boulder | 56 | 56 | 52 | 50 | 50 | 42 | 43 | 44 | 43 | 47 | 52 | 57 |
| Difference | -20 | -19 | -23 | -26 | -28 | -36 | -36 | -35 | -36 | -32 | -27 | -20 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Castries | 76 | 75 | 75 | 76 | 77 | 79 |
| Boulder | 56 | 56 | 52 | 50 | 50 | 42 |
| Difference | -20 | -19 | -23 | -26 | -28 | -36 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Castries | 79 | 79 | 79 | 79 | 79 | 77 |
| Boulder | 43 | 44 | 43 | 47 | 52 | 57 |
| Difference | -36 | -35 | -36 | -32 | -27 | -20 |
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 → · Boulder trends →
Boulder from Cfa to BSk.
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.
Boulder
Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Brighton 3 SE (NOAA GHCN station USC00050950), about 38 km from the city centre.
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.
← change Castries · change Boulder → · Castries page · Boulder page