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San Juan, Puerto Rico climate
Am Tropical monsoon
San Juan has a remarkably steady tropical climate (Tropical monsoon, Köppen Am). The hottest month is August with an average daily high near 32°C, while the coldest is January averaging around 22°C at night. Around 1516 mm of precipitation falls each year, peaking in November (187 mm) and easing off in March (55 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 countsSan Juan climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 29 | 29 | 29 | 30 | 31 | 32 | 32 | 32 | 32 | 31 | 30 | 29 |
| Avg temp (°C) | 25 | 25 | 26 | 27 | 28 | 28 | 28 | 29 | 29 | 28 | 27 | 26 |
| Avg low (°C) | 22 | 22 | 22 | 23 | 24 | 25 | 25 | 25 | 25 | 25 | 24 | 23 |
| Precipitation (mm) | 103 | 65 | 55 | 117 | 141 | 118 | 153 | 160 | 165 | 129 | 187 | 123 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 29 | 29 | 29 | 30 | 31 | 32 |
| Avg temp (°C) | 25 | 25 | 26 | 27 | 28 | 28 |
| Avg low (°C) | 22 | 22 | 22 | 23 | 24 | 25 |
| Precipitation (mm) | 103 | 65 | 55 | 117 | 141 | 118 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 32 | 32 | 32 | 31 | 30 | 29 |
| Avg temp (°C) | 28 | 29 | 29 | 28 | 27 | 26 |
| Avg low (°C) | 25 | 25 | 25 | 25 | 24 | 23 |
| Precipitation (mm) | 153 | 160 | 165 | 129 | 187 | 123 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 18 | 15 | 13 | 14 | 17 | 15 | 19 | 20 | 18 | 18 | 21 | 20 |
| Days with high ≥ 32°C (days) | 0.1 | 0.8 | 2 | 4 | 7 | 12 | 10 | 13 | 13 | 10 | 2 | 0.5 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 18 | 15 | 13 | 14 | 17 | 15 |
| Days with high ≥ 32°C (days) | 0.1 | 0.8 | 2 | 4 | 7 | 12 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 19 | 20 | 18 | 18 | 21 | 20 |
| Days with high ≥ 32°C (days) | 10 | 13 | 13 | 10 | 2 | 0.5 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 56 | 56 | 57 | 56 | 67 | 64 | 61 | 59 | 63 | 59 | 59 | 55 |
| Clear days (≤ 30% cloud) | 4 | 3 | 3 | 4 | 2 | 3 | 3 | 3 | 3 | 4 | 4 | 4 |
| Partly cloudy days (30–70%) | 20 | 19 | 20 | 18 | 14 | 14 | 17 | 18 | 16 | 16 | 17 | 20 |
| Cloudy days (≥ 70%) | 7 | 6 | 7 | 8 | 15 | 13 | 11 | 10 | 11 | 11 | 10 | 7 |
| Relative humidity (%) | 78 | 76 | 74 | 75 | 78 | 79 | 79 | 79 | 80 | 81 | 81 | 79 |
| Wind speed (m/s) | 4.2 | 4.2 | 4.0 | 3.9 | 3.8 | 4.1 | 4.4 | 4.1 | 3.5 | 3.3 | 3.7 | 4.1 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 56 | 56 | 57 | 56 | 67 | 64 |
| Clear days (≤ 30% cloud) | 4 | 3 | 3 | 4 | 2 | 3 |
| Partly cloudy days (30–70%) | 20 | 19 | 20 | 18 | 14 | 14 |
| Cloudy days (≥ 70%) | 7 | 6 | 7 | 8 | 15 | 13 |
| Relative humidity (%) | 78 | 76 | 74 | 75 | 78 | 79 |
| Wind speed (m/s) | 4.2 | 4.2 | 4.0 | 3.9 | 3.8 | 4.1 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 61 | 59 | 63 | 59 | 59 | 55 |
| Clear days (≤ 30% cloud) | 3 | 3 | 3 | 4 | 4 | 4 |
| Partly cloudy days (30–70%) | 17 | 18 | 16 | 16 | 17 | 20 |
| Cloudy days (≥ 70%) | 11 | 10 | 11 | 11 | 10 | 7 |
| Relative humidity (%) | 79 | 79 | 80 | 81 | 81 | 79 |
| Wind speed (m/s) | 4.4 | 4.1 | 3.5 | 3.3 | 3.7 | 4.1 |
Methodology & sources
Temperature & precipitation — 1991–2020 normals computed from 30 years of daily observations at San Juan L M Marin Intl AP, a weather station, about 11 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.