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Rio Claro weather by month: averages, rainfall & climate trends

Temperature-wise, the seasons in Rio Claro are gentle: monthly means drift only 6.2°C over the whole year. Rainfall leans toward the stretch from October to March. Rio Claro weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.

Today vs average

+0.8°Chigh near average

29° / 13°Today
28° / 17°Average
see today in detail →

How it's changed

+1.9°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–49135days above 30°C a year now (2016–2025) · 18 in the 1940sdays above 30°C · 18 in the 1940s+1.9°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 266 mmhigh 29°low 20°February, rain 226 mmhigh 29°low 20°March, rain 178 mmhigh 28°low 19°April, rain 84 mmhigh 27°low 17°May, rain 67 mmhigh 25°low 15°June, rain 43 mmhigh 24°low 13°July, rain 39 mmhigh 24°low 12°August, rain 36 mmhigh 26°low 14°September, rain 77 mmhigh 28°low 16°October, rain 157 mmhigh 28°low 17°November, rain 183 mmhigh 28°low 18°December, rain 254 mmhigh 28°low 19°wettest month January, 266 mm · 1,609 mm a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Partly cloudy

Right now

14.1°

14°feels like
89%humidity
12°dew point
7 km/hfrom S
UV index0.1
sunrise05:32sunset18:16day length12h 44m
TodayPartly cloudy29°13°
ThuOvercast27°17°
FriShowers22°18°
SatShowers26°20°
SunShowers22°17°
MonPartly cloudy22°14°
TueOvercast26°14°

On this date: October 21

Today (forecast)
29° / 13°
Average for October 21
28° / 17°

High near average · +0.8°C

  • Highest since 1940: 36.8° · 1963
  • Lowest since 1940: 10.6° · 2025
  • One year ago: 25° / 11°

Every October 21 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 21 on record (n = 86). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for Rio Claro is sampled from the ECMWF ERA5 reanalysis at 22.41°S, 47.56°W, with daily records since 1940.

Coordinates
22.41°S, 47.56°W
Time zone
America/Sao Paulo
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

14 of the last 30 days were warmer than the historical average for that date. Average difference: +0.3°C.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

The year peaks in February, at around 28.7°C by mid-afternoon, with nights around 19.9°C. On about 105 nights a year, the temperature never drops below 20°C. In July, the coolest month, afternoons reach about 24.1°C and nights dip to 12.5°C. Frost is essentially unknown.

The yearly total for Rio Claro comes to about 1,609 mm; monthly amounts range from 36 mm in August up to 266 mm in January.

The record here starts in 1940, and since then the annual mean in Rio Claro has climbed 1.9°C from the first ten years to the last ten. Days above 30°C have grown noticeably more frequent, from around 20 a year in the first decade to about 135 in the last.

Climate graph (climograph)

February is the warmest month, July the coolest: a yearly swing of 6°C. Wettest month: January (~266 mm). Whole year averages ~1,609 mm of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

Rio Claro month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Highest and Lowest are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainDaylightHighestLowest
January28.6°19.9°266 mm13.2 h39.4° (2015)11.9° (1943)
February28.7°19.9°226 mm12.7 h37.7° (2014)14.1° (1940)
March28.3°19.2°178 mm12.2 h35.3° (2018)11.9° (1987)
April26.9°17.1°84 mm11.5 h33.9° (2016)6.3° (1971)
May24.7°14.5°67 mm10.9 h33.1° (2024)4.6° (1990)
June23.8°13.1°43 mm10.6 h31.3° (2010)2.1° (1994)
July24.1°12.5°39 mm10.8 h31.4° (2016)2.0° (1994)
August26.3°13.8°36 mm11.2 h34.8° (1944)4.3° (2011)
September27.9°15.9°77 mm11.9 h38.5° (1961)6.0° (2006)
October28.0°17.5°157 mm12.5 h39.4° (2020)9.3° (1973)
November28.0°18.2°183 mm13.1 h38.5° (2023)9.9° (1956)
December28.1°19.4°254 mm13.4 h36.2° (2018)11.9° (1952)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +1.9°C.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.26°C per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Mar–May is warming fastest: +0.29°C per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 30°C per year: 17.9 early in the record → 134.7 recently. Frost days: 0 → 0.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

Hottest day since 1940 in 2020, coldest in 1994: 39.4°C / 2.0°C.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~1,609 mm/year on average. Last decade: −24% vs that average. Long-term trend: −54 mm per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about Rio Claro

Which is the warmest month in Rio Claro?
On long-term average, the warmest month in Rio Claro is February (mean daily temperature of about 23.9°C) and the coolest is July (about 17.7°C).
How does today's temperature in Rio Claro compare to the historical average?
On October 21, 2026, Rio Claro is forecast to reach a high of 28.5°C and a low of 13.1°C. The long-term average for this date (the full record since 1940) is a high of 27.7°C and a low of 17.4°C, so today's high is 0.8°C warmer than that average.
How much has Rio Claro warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Rio Claro is about 1.9°C warmer.
How much does it rain in Rio Claro?
Rio Claro receives about 1,609 mm of precipitation per year on long-term average, with January typically the wettest month.
What is the average temperature in Rio Claro?
Over the full record (since 1940), the annual mean temperature in Rio Claro is about 21.3°C. The warmest month is February and the coolest is July.
What are the average temperatures in Rio Claro by month?
Average daily highs and lows for each month in Rio Claro (°C, full record since 1940): January 29°/20°, February 29°/20°, March 28°/19°, April 27°/17°, May 25°/15°, June 24°/13°, July 24°/12°, August 26°/14°, September 28°/16°, October 28°/17°, November 28°/18°, December 28°/19°.
What is the weather like in Rio Claro in summer?
Summer in Rio Claro (December to February) is wet and warm. Afternoons run 28–29°C and nights 19–20°C; February is the warmest month. Rain is steady at around 249 mm a month. It is the wettest season of the year.
What is the weather like in Rio Claro in winter?
In winter, June through August, Rio Claro is pleasantly warm. Expect 24–26°C by day and 12–14°C at night, with July the coldest month. About 39 mm of rain a month. It is the driest season of the year.
What is the weather like in Rio Claro in spring?
September to November is spring in Rio Claro, and it is wet and warm. Daytime highs sit at 28°C and nights at 16–18°C; October is the warmest month. Rain rises from 77 mm in September to 183 mm in November.
What is the weather like in Rio Claro in autumn?
Autumn in Rio Claro (March to May) is wet and warm. Afternoons run 25–28°C and nights 15–19°C; May is the coldest month. Rain falls off from 178 mm in March to 67 mm in May.

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