Climate averages 1991–2020
San Juan, Peru weather
by month.
See how the year changes. October has the highest average daily maximum; August has the lowest average monthly rainfall.
Long-term climate patterns, not a forecast for a particular trip.
Across the year San Juan, Peru averages a daytime high of 29.5°C and a nighttime low of 23.1°C, with about 2,772 mm of rain on roughly 305 days. October is the warmest month (average high 30.3°C) and June the coolest (28.2°C). March is the wettest month with 304 mm; August is the driest with 154 mm.
The annual picture
A year in San Juan
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Juan, Peru climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 30.0°C23.4°C | 23.4°C | 252 | 25.9 | 12.312 h |
| February | 30.0°C23.5°C | 23.5°C | 235 | 24.7 | 12.212 h |
| March | 29.9°C23.5°C | 23.5°C | 304 | 28.4 | 12.112 h |
| April | 29.4°C23.3°C | 23.3°C | 294 | 27.3 | 12.012 h |
| May | 28.8°C22.9°C | 22.9°C | 271 | 26.7 | 11.912 h |
| June | 28.2°C22.4°C | 22.4°C | 218 | 25.0 | 11.912 h |
| July | 28.3°C22.1°C | 22.1°C | 165 | 23.3 | 11.912 h |
| August | 29.4°C22.5°C | 22.5°C | 154 | 21.8 | 12.012 h |
| September | 30.1°C23.1°C | 23.1°C | 179 | 23.5 | 12.112 h |
| October | 30.3°C23.5°C | 23.5°C | 201 | 25.8 | 12.212 h |
| November | 29.9°C23.5°C | 23.5°C | 235 | 25.8 | 12.312 h |
| December | 29.9°C23.4°C | 23.4°C | 263 | 27.2 | 12.312 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
Nearby cities
- IquitosPeru · 4 kmHigh 29.5°C · Low 23.0°C · 2,772 mm rain a year
- Cruzeiro do SulBrazil · 433 kmHigh 29.4°C · Low 22.3°C · 2,077 mm rain a year
- PucallpaPeru · 531 kmHigh 29.5°C · Low 22.9°C · 2,598 mm rain a year
- CuencaEcuador · 642 kmHigh 17.7°C · Low 10.8°C · 1,499 mm rain a year
- FlorenciaColombia · 653 kmHigh 26.7°C · Low 18.4°C · 2,076 mm rain a year
- LojaEcuador · 658 kmHigh 21.0°C · Low 14.2°C · 1,310 mm rain a year
- PitalitoColombia · 698 kmHigh 22.6°C · Low 14.6°C · 3,140 mm rain a year
- IpialesColombia · 705 kmHigh 15.7°C · Low 9.0°C · 2,434 mm rain a year
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsWhat do the high and low temperatures mean?
We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.
How is a rain day counted?
A local calendar day (standard time, UTC-5, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.
Where do the numbers come from?
ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at -3.80°, -73.30° (3 km from the city centre). Rain comes from the 0.25° cell at -3.75°, -73.25°. Iquitos lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells. These are model estimates, not weather-station readings; coast, hills and city streets can differ.
Does this page show sunshine, humidity or sea temperature?
No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.