Climate averages 1991–2020

Japeri weather
by month.

See how the year changes. February has the highest average daily maximum; August has the lowest average monthly rainfall.

Pleasant-weather months by our simple rule: JuneJulyAugust

Long-term climate patterns, not a forecast for a particular trip.

Warmest month 31.7°C February, average high
Coolest month 16.0°C July, average low
Wettest month 273 mm January, monthly total
Driest month 35 mm August, monthly total
The year at a glance · average highYear overview

Across the year Japeri averages a daytime high of 28.5°C and a nighttime low of 19.9°C, with about 1,570 mm of rain on roughly 166 days. February is the warmest month (average high 31.7°C) and July the coolest (25.7°C). January is the wettest month with 273 mm; August is the driest with 35 mm.

Months with pleasant weather by a simple rule (average high between 18°C and 29°C, average low of at least 5°C and at most 8 rain days): June, July and August. This looks at temperature and rain only, not humidity, wind, sea temperature or crowds.

The annual picture

A year in Japeri

30-year average
Average highAverage low°C
Average daily high and low temperatures by month The same values are available in the monthly table below. Lines show mean daily maxima and minima, not a forecast interval. 101520253035 JanFebMarAprMayJunJulAugSepOctNovDec

Monthly rainfall

Average total · mm
Average monthly rainfall totalsEach bar is a mean monthly total over 1991–2020. Full numbers are in the table. JanFebMarAprMayJunJulAugSepOctNovDec 3000

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Japeri climate table

1991–2020
Monthly climate averages for Japeri, 1991–2020
MonthAverage highHigh / lowAverage lowRainfall mm/monthRain days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 31.3°C23.1°C23.1°C27320.913.313 h
February 31.7°C23.1°C23.1°C19917.712.913 h
March 30.1°C22.4°C22.4°C20020.212.212 h
April 28.5°C20.7°C20.7°C10613.011.612 h
May 26.3°C18.1°C18.1°C6710.211.011 h
June 26.0°C16.6°C16.6°C406.710.811 h
July 25.7°C16.0°C16.0°C406.310.911 h
August 26.9°C16.6°C16.6°C356.711.311 h
September 28.0°C18.5°C18.5°C7911.011.912 h
October 29.0°C20.1°C20.1°C11413.912.613 h
November 28.7°C21.0°C21.0°C19018.613.213 h
December 30.3°C22.3°C22.3°C22620.713.513 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

Distance from Japeri

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 limits
What 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-3, 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 -22.60°, -43.70° (7 km from the city centre), adjusted up by 1.5°C for the difference between the city's elevation (32 m) and the cell's (268 m). Rain comes from the 0.25° cell at -22.75°, -43.75°. Itaguaí and Seropédica lie in the same rainfall cell, so their 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.