El Niño in San Juan
During El Niño, San Juan gets on average 26% less rain in October–December than in neutral years (343 mm vs 467 mm).
Weather in San Juan: next 7 days
San Juan
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Weather forecast: MET Norway (CC BY 4.0), updated every hour. For official warnings, follow your national weather service.
El Niño is active right now: the El Niño columns show what San Juan typically sees in this phase.
Monthly rainfall by phase
El NiñoNeutralLa Niña
Month by month
| Month | El Niño | Neutral | La Niña | Change El Niño | Temp. El Niño / neutral |
|---|---|---|---|---|---|
| January | 62 mm | 66 mm | 63 mm | -6% | 25.2 / 24.8 °C |
| February | 63 mm | 57 mm | 65 mm | +9% | 25.3 / 24.9 °C |
| March | 61 mm | 77 mm | 63 mm | -20% | 25.7 / 25.3 °C |
| April | 105 mm | 91 mm | 65 mm | +15% | 26.4 / 26.1 °C |
| May | 210 mm | 141 mm | 96 mm | +49% | 26.6 / 26.9 °C |
| June | 100 mm | 103 mm | 101 mm | -3% | 27.3 / 27.4 °C |
| July | 94 mm | 110 mm | 130 mm | -15% | 27.7 / 27.6 °C |
| August | 111 mm | 133 mm | 160 mm | -17% | 28.0 / 27.9 °C |
| September | 145 mm | 175 mm | 196 mm | -17% | 28.0 / 27.8 °C |
| October | 141 mm | 193 mm | 163 mm | -27% | 27.5 / 27.3 °C |
| November | 136 mm | 173 mm | 141 mm | -21% | 26.6 / 26.3 °C |
| December | 66 mm | 101 mm | 71 mm | -34% | 25.6 / 25.3 °C |
NASA POWER (MERRA-2), 1981–2025, classified by NOAA ONI. Averages, not a forecast.
Frequently asked questions
How does El Niño affect San Juan?
During El Niño, San Juan gets on average 26% less rain in October–December than in neutral years (343 mm vs 467 mm).
And La Niña?
In October–December, La Niña years average 375 mm, compared with 467 mm in neutral years.
Where does this data come from?
Monthly rainfall and temperature from NASA POWER (MERRA-2 reanalysis, 1981–2025) at 18.47, -66.11, classified by NOAA's Oceanic Niño Index for each month. These are averages; each event is different.