WeatherJourney.com

Rancagua weather by month: averages, rainfall & climate trends

Average temperatures in Rancagua follow a clear seasonal rhythm, rising and falling by 13.7°C over the course of the year. The warm months are largely dry. Most of the year's rain arrives between May and September. Rancagua weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.

Today vs average

−2.9°Chigh below average

20° / 13°Today
22° / 8°Average
see today in detail →

How it's changed

+0.2°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4911frost days a year now (2016–2025) · 12 in the 1940sfrost days a year · 12 in the 1940s33days above 30°C a year now (2016–2025) · 39 in the 1940sdays above 30°C · 39 in the 1940s+0.2°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 8 mmhigh 29°low 16°February, rain 7 mmhigh 28°low 15°March, rain 10 mmhigh 26°low 13°April, rain 37 mmhigh 23°low 9°May, rain 102 mmhigh 19°low 6°June, rain 162 mmhigh 16°low 4°July, rain 142 mmhigh 16°low 3°August, rain 112 mmhigh 17°low 4°September, rain 89 mmhigh 19°low 6°October, rain 60 mmhigh 21°low 8°November, rain 27 mmhigh 24°low 10°December, rain 13 mmhigh 27°low 13°wettest month June, 162 mm · 767 mm a yearsee month by month →

Right now

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

Right now

13.1°

12°feels like
78%humidity
9°dew point
6 km/hfrom NE
UV index0.0
sunrise06:53sunset20:01day length13h 08m
TodayOvercast20°13°
ThuPartly cloudy20°13°
FriPartly cloudy19°11°
SatOvercast16°9°
SunOvercast24°9°
MonOvercast22°15°
TuePartly cloudy22°13°

On this date: October 21

Today (forecast)
20° / 13°
Average for October 21
22° / 8°

High below average · −2.9°C

  • Highest since 1940: 28.3° · 1999
  • Lowest since 1940: 0.2° · 1954
  • One year ago: 23° / 9°

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 Rancagua is sampled from the ECMWF ERA5 reanalysis at 34.17°S, 70.74°W, with daily records since 1940.

Coordinates
34.17°S, 70.74°W
Time zone
America/Santiago
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

17 of the last 30 days were warmer than the historical average for that date. Average difference: +0.8°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

January brings the year's peak warmth, with afternoons typically reaching 28.7°C and nights around 15.8°C. In a typical recent year, around 35 days reach 30°C or more. In July, the coolest month, afternoons reach about 15.5°C and nights dip to 3.4°C. Frost shows up on around 11 mornings a year.

Rancagua picks up roughly 767 mm a year, with a peak of 162 mm in June and as little as 7 mm in February.

Comparing the record's first decade with its most recent one, Rancagua now averages 0.2°C warmer than it did in the 1940s. The last decade has also run drier, about 13% below the long-term precipitation average.

Climate graph (climograph)

January is the warmest month, July the coolest: a yearly swing of 14°C. Wettest month: June (~162 mm). Whole year averages ~767 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).

Rainy days by month

About 55 rainy days a year: most in June (~9), fewest in January (~1).

Bars = average number of days with ≥ 2 mm per month. Hover for the monthly rainfall total.

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.

Rancagua 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 lowRainRainy daysDaylightHighestLowest
January28.7°15.8°8 mm114.0 h38.0° (1941)7.4° (1990)
February28.3°15.2°7 mm113.2 h35.4° (1942)6.7° (1984)
March26.4°12.8°10 mm112.3 h34.6° (1961)3.2° (1982)
April22.7°9.1°37 mm311.1 h32.3° (1941)−1.2° (1985)
May18.9°6.5°102 mm610.2 h29.1° (2002)−5.1° (1958)
June15.8°4.3°162 mm99.7 h27.2° (1941)−11.6° (1945)
July15.5°3.4°142 mm89.9 h25.3° (1941)−9.2° (1957)
August17.1°4.3°112 mm810.7 h28.8° (1942)−8.1° (1991)
September18.9°6.1°89 mm811.8 h30.4° (2021)−8.0° (1961)
October21.2°8.0°60 mm712.9 h31.9° (2024)−5.3° (1991)
November24.4°10.5°27 mm313.8 h33.4° (1960)1.8° (2010)
December27.2°13.5°13 mm114.3 h36.9° (1941)4.7° (2014)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +0.2°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: −0.02°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

Sep–Nov is warming fastest: +0.06°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: 39.4 early in the record → 33.3 recently. Frost days: 12 → 11.

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 1941, coldest in 1945: 38.0°C / −11.6°C.

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

Annual rainfall

~767 mm/year on average. Last decade: −13% vs that average. Long-term trend: −2 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 Rancagua

Which is the warmest month in Rancagua?
On long-term average, the warmest month in Rancagua is January (mean daily temperature of about 22.4°C) and the coolest is July (about 8.7°C).
How does today's temperature in Rancagua compare to the historical average?
On October 21, 2026, Rancagua is forecast to reach a high of 19.5°C and a low of 13.0°C. The long-term average for this date (the full record since 1940) is a high of 22.4°C and a low of 8.3°C, so today's high is 2.9°C cooler than that average.
How much has Rancagua warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Rancagua is about 0.2°C warmer.
How much does it rain in Rancagua?
Rancagua receives about 767 mm of precipitation per year on long-term average, with June typically the wettest month.
What is the average temperature in Rancagua?
Over the full record (since 1940), the annual mean temperature in Rancagua is about 15.6°C. The warmest month is January and the coolest is July.
What are the average temperatures in Rancagua by month?
Average daily highs and lows for each month in Rancagua (°C, full record since 1940): January 29°/16°, February 28°/15°, March 26°/13°, April 23°/9°, May 19°/6°, June 16°/4°, July 16°/3°, August 17°/4°, September 19°/6°, October 21°/8°, November 24°/10°, December 27°/13°.
What is the weather like in Rancagua in summer?
Summer in Rancagua (December to February) is dry and warm. Daytime highs sit at 27–29°C and nights at 13–16°C; January is the warmest month. Hardly any rain falls.
What is the weather like in Rancagua in winter?
In winter, June through August, Rancagua is wet and fairly mild. Afternoons run 16–17°C and nights 3–4°C; July is the coldest month. Rain is steady at around 139 mm a month, spread over roughly 8 days. It is the wettest season of the year.
What is the weather like in Rancagua in spring?
September to November is spring in Rancagua, and it is mild. It warms from 19°C by day and 6°C at night in September to 24°C and 10°C in November. Rain eases through the season: 8 rainy days and 89 mm in September, 3 days and 27 mm in November.
What is the weather like in Rancagua in autumn?
In autumn, March through May, Rancagua is pleasantly warm. March is still 26°C by day and 13°C at night; by May it is down to 19°C and 6°C. Rain picks up through the season: 1 rainy day and 10 mm in March, 6 days and 102 mm in May.
How many days a year does it rain in Rancagua?
On long-term average, Rancagua has about 55 days a year with at least 2 mm of rain or snow. The annual total is roughly 767 mm.

Weather in nearby cities