Climate averages 1991–2020

Rio das Ostras weather
in January.

A hot, very wet month: the 2nd warmest and the 11th driest of the year.

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

Average high 29.4°C Daytime mean, January

Average low 23.2°C Night-time mean, January

Rainfall 206 mm 17 days with ≥1 mm

Daylight 13 h Sunrise to sunset, per day

January is a hot month in Rio das Ostras: daytime highs average 29.4°C and nights cool to about 23.2°C. By daytime temperature it is the 2nd warmest of the 12 months.

Expect about 206 mm of rain on roughly 17 days, which makes January a very wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 21 min on an average January day.

The nearest other city in this atlas is Macaé (23 km away). In January its highs average 29.0°C, about as warm as Rio das Ostras, with 139 mm of rain.

Among the 448 cities listed in Brazil, Rio das Ostras ranks joint 128th of 448 for the warmest January highs and 176th of 448 for the driest January (rainfall, lowest first). The mean January high of those 448 cities is 28.5°C; Rio das Ostras is 0.9°C warmer than that mean.

From January to February, average highs rise by 0.4°C to 29.8°C, and monthly rainfall falls from 206 mm to 141 mm.

The annual picture

January in context

30-year average

Average highAverage low°C

Monthly rainfall

Average total · mm

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

Every month, side by side

Rio das Ostras climate table

1991–2020

Monthly climate averages for Rio das Ostras, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January, selected	29.4°C23.2°C	23.2°C	206	16.5	13.313 h
February	29.8°C23.4°C	23.4°C	141	12.8	12.913 h
March	28.6°C22.8°C	22.8°C	172	17.6	12.212 h
April	27.2°C21.3°C	21.3°C	85	12.1	11.612 h
May	25.1°C19.1°C	19.1°C	60	9.5	11.111 h
June	24.7°C17.9°C	17.9°C	31	5.9	10.811 h
July	24.4°C17.4°C	17.4°C	29	5.6	10.911 h
August	25.0°C17.8°C	17.8°C	34	6.5	11.311 h
September	25.7°C18.9°C	18.9°C	73	10.0	11.912 h
October	26.6°C20.2°C	20.2°C	108	11.9	12.613 h
November	26.8°C21.0°C	21.0°C	203	17.5	13.213 h
December	28.4°C22.4°C	22.4°C	222	19.0	13.513 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

January in nearby cities

Distance from Rio das Ostras

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

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Rio das Ostras) is explained once on the Rio das Ostras year overview and on the Sources, method and limits page.