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Callao weather by month: averages, rainfall & climate trends

Temperature-wise, the seasons in Callao are gentle: monthly means drift only 5.6°C over the whole year. Rain is a rare event here. Callao weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

+8.7°Chigh well above average

26° / 21°Today
17° / 16°Average
see today in detail →

How it's changed

+0.2°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–491days above 25°C a year now (2016–2025) · 0 in the 1940sdays above 25°C · 0 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 11 mmhigh 21°low 20°February, rain 13 mmhigh 22°low 21°March, rain 10 mmhigh 22°low 21°April, rain 8 mmhigh 20°low 19°May, rain 15 mmhigh 19°low 18°June, rain 21 mmhigh 18°low 17°July, rain 20 mmhigh 17°low 16°August, rain 18 mmhigh 16°low 15°September, rain 14 mmhigh 16°low 15°October, rain 12 mmhigh 17°low 16°November, rain 10 mmhigh 18°low 17°December, rain 9 mmhigh 20°low 18°wettest month June, 21 mm · 161 mm a yearsee month by month →

Right now

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

Right now

25.0°

26°feels like
65%humidity
18°dew point
13 km/hfrom S
UV index3.7
sunrise05:41sunset18:05day length12h 24m
TodayPartly cloudy26°21°
MonMostly clear25°21°
TuePartly cloudy26°22°
WedOvercast26°22°
ThuOvercast25°22°
FriOvercast25°22°
SatOvercast25°22°

On this date: October 18

Today (forecast)
26° / 21°
Average for October 18
17° / 16°

High well above average · +8.7°C

  • Record high: 20.0° · 1997
  • Record low: 12.5° · 1954
  • One year ago: 17° / 16°

Every October 18 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 18 on record (n = 87). 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 Callao is sampled from the ECMWF ERA5 reanalysis at 12.05°S, 77.13°W, with daily records since 1940.

Coordinates
12.05°S, 77.13°W
Time zone
America/Lima
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

31 of the last 31 days were warmer than the historical average for that date. Average difference: +5.7°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 22.3°C by mid-afternoon, with nights around 20.8°C. Around 80 nights a year stay above 20°C. In September, the coolest month, afternoons reach about 16.4°C and nights dip to 15.3°C. Frost is essentially unknown.

Callao averages only about 161 mm a year, and what little falls comes mostly around June.

Comparing the record's first decade with its most recent one, Callao now averages 0.2°C warmer than it did in the 1940s. Recent years have brought less rain as well. The last decade sits roughly 13% under the long-term average.

Climate graph (climograph)

February is the warmest month, September the coolest: a yearly swing of 6°C. Wettest month: June (~21 mm). Whole year averages ~161 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.

Callao 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. Record high/low are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainDaylightRecord highRecord low
January21.5°20.1°11 mm12.6 h27.2° (1983)16.3° (1974)
February22.3°20.8°13 mm12.4 h27.2° (1983)17.1° (1955)
March21.9°20.6°10 mm12.1 h26.5° (1983)17.0° (1974)
April20.3°19.1°8 mm11.7 h25.9° (1983)15.5° (1964)
May18.6°17.6°15 mm11.4 h25.4° (1983)14.2° (1955)
June17.6°16.6°21 mm11.3 h23.1° (1997)13.3° (1954)
July16.9°15.9°20 mm11.4 h22.6° (1997)11.9° (1954)
August16.4°15.4°18 mm11.6 h22.4° (1997)12.6° (1964)
September16.4°15.3°14 mm11.9 h22.2° (1997)13.1° (1954)
October16.8°15.7°12 mm12.3 h20.9° (1997)11.9° (1954)
November17.9°16.7°10 mm12.6 h23.7° (1982)13.8° (1954)
December19.7°18.4°9 mm12.7 h25.4° (1982)15.6° (1975)

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: +0.07°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

Dec–Feb is warming fastest: +0.10°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 ≥ 25°C per year: 0.0 early in the record → 1.0 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

All-time high in 1983, all-time low in 1954: 27.2°C / 11.9°C.

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

Annual rainfall

~161 mm/year on average. Last decade: −13% vs that average. Long-term trend: −3 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 Callao

Which is the warmest month in Callao?
On long-term average, the warmest month in Callao is February (mean daily temperature of about 21.4°C) and the coolest is September (about 15.8°C).
How does today's temperature in Callao compare to the historical average?
On October 18, 2026, Callao is forecast to reach a high of 25.5°C and a low of 21.2°C. The long-term average for this date (the full record since 1940) is a high of 16.8°C and a low of 15.7°C, so today's high is 8.7°C warmer than that average.
How much has Callao warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Callao is about 0.2°C warmer.
How much does it rain in Callao?
Callao receives about 161 mm of precipitation per year on long-term average, with June typically the wettest month.
What is the average temperature in Callao?
Over the full record (since 1940), the annual mean temperature in Callao is about 18.2°C. The warmest month is February and the coolest is September.
What are the average temperatures in Callao by month?
Average daily highs and lows for each month in Callao (°C, full record since 1940): January 21°/20°, February 22°/21°, March 22°/21°, April 20°/19°, May 19°/18°, June 18°/17°, July 17°/16°, August 16°/15°, September 16°/15°, October 17°/16°, November 18°/17°, December 20°/18°.
What is the weather like in Callao in summer?
Summer in Callao (December to February) is dry and mild. Afternoons run 20–22°C and nights 18–21°C; February is the warmest month. About 11 mm of rain a month.
What is the weather like in Callao in winter?
Winter in Callao (June to August) is dry and fairly mild. Expect 16–18°C by day and 15–17°C at night, with August the coldest month. Rain is steady at around 20 mm a month.
What is the weather like in Callao in spring?
Spring in Callao (September to November) is dry and fairly mild. Daytime highs sit at 16–18°C and nights at 15–17°C; November is the warmest month. About 12 mm of rain a month.
What is the weather like in Callao in autumn?
Autumn in Callao (March to May) is dry and mild. Afternoons run 19–22°C and nights 18–21°C; May is the coldest month. Rain is steady at around 11 mm a month.

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