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Formosa weather by month: averages, rainfall & climate trends

Average temperatures in Formosa follow a clear seasonal rhythm, rising and falling by 10.8°C over the course of the year. Rainfall leans toward the stretch from October to April. Formosa weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.

Today vs average

−0.9°Chigh near average

27° / 21°Today
28° / 18°Average
see today in detail →

How it's changed

+0.5°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–49163days above 30°C a year now (2016–2025) · 103 in the 1940sdays above 30°C · 103 in the 1940s+0.5°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 151 mmhigh 33°low 23°February, rain 145 mmhigh 32°low 22°March, rain 137 mmhigh 30°low 21°April, rain 155 mmhigh 27°low 18°May, rain 127 mmhigh 24°low 15°June, rain 99 mmhigh 22°low 13°July, rain 72 mmhigh 22°low 13°August, rain 82 mmhigh 24°low 14°September, rain 131 mmhigh 26°low 15°October, rain 182 mmhigh 28°low 18°November, rain 168 mmhigh 30°low 20°December, rain 158 mmhigh 32°low 22°wettest month October, 182 mm · 1,605 mm a yearsee month by month →

Right now

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

Right now

26.3°

27°feels like
69%humidity
20°dew point
20 km/hfrom E
UV index5.8
sunrise06:11sunset19:02day length12h 51m
TodayShowers27°21°
ThuClear34°22°
FriOvercast36°23°
SatOvercast26°20°
SunPartly cloudy23°16°
MonPartly cloudy24°11°
TueOvercast25°16°

On this date: October 21

Today (forecast)
27° / 21°
Average for October 21
28° / 18°

High near average · −0.9°C

  • Highest since 1940: 36.6° · 1991
  • Lowest since 1940: 10.1° · 1946
  • One year ago: 28° / 17°

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 = 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 Formosa is sampled from the ECMWF ERA5 reanalysis at 26.18°S, 58.17°W, with daily records since 1940.

Coordinates
26.18°S, 58.17°W
Time zone
America/Argentina/Cordoba
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

11 of the last 31 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 January, at around 32.6°C by mid-afternoon, with nights around 22.9°C. On about 155 nights a year, the temperature never drops below 20°C. In July, the coolest month, afternoons reach about 22.0°C and nights dip to 12.7°C. Freezing temperatures almost never occur.

Formosa picks up roughly 1,605 mm a year, with a peak of 182 mm in October and as little as 72 mm in July.

The record here starts in 1940, and since then the annual mean in Formosa has climbed 0.5°C from the first ten years to the last ten. The count of days past 30°C has risen from roughly 105 a year to 165 between the record's first and last decades.

Climate graph (climograph)

January is the warmest month, July the coolest: a yearly swing of 11°C. Wettest month: October (~182 mm). Whole year averages ~1,605 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 101 rainy days a year: most in January (~11), fewest in July (~6).

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.

Formosa 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
January32.6°22.9°151 mm1113.5 h41.3° (2022)13.4° (1980)
February31.7°22.5°145 mm1012.9 h40.3° (2025)11.9° (2023)
March30.4°21.2°137 mm1012.2 h40.8° (2024)8.2° (1964)
April27.1°18.2°155 mm911.4 h36.5° (2024)6.0° (1995)
May23.8°15.3°127 mm710.7 h34.9° (2018)1.8° (1979)
June21.7°13.4°99 mm710.4 h32.7° (2003)0.2° (1961)
July22.0°12.7°72 mm610.5 h33.5° (2017)−0.8° (2017)
August23.9°13.6°82 mm611.1 h38.6° (2020)0.0° (2013)
September25.8°15.4°131 mm811.9 h41.9° (2020)2.7° (2002)
October27.9°17.9°182 mm1012.6 h43.1° (2020)6.2° (1981)
November29.8°19.6°168 mm913.3 h41.1° (1942)7.9° (2022)
December31.7°21.7°158 mm1013.6 h40.7° (1985)10.5° (1971)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +0.5°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: +0.09°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: +0.13°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: 103.2 early in the record → 162.7 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 2017: 43.1°C / −0.8°C.

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

Annual rainfall

~1,605 mm/year on average. Last decade: −18% vs that average. Long-term trend: −30 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 Formosa

Which is the warmest month in Formosa?
On long-term average, the warmest month in Formosa is January (mean daily temperature of about 27.5°C) and the coolest is July (about 16.7°C).
How does today's temperature in Formosa compare to the historical average?
On October 21, 2026, Formosa is forecast to reach a high of 27.4°C and a low of 21.0°C. The long-term average for this date (the full record since 1940) is a high of 28.3°C and a low of 17.7°C, so today's high is 0.9°C cooler than that average.
How much has Formosa warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Formosa is about 0.5°C warmer.
How much does it rain in Formosa?
Formosa receives about 1,605 mm of precipitation per year on long-term average, with October typically the wettest month.
What is the average temperature in Formosa?
Over the full record (since 1940), the annual mean temperature in Formosa is about 22.2°C. The warmest month is January and the coolest is July.
What are the average temperatures in Formosa by month?
Average daily highs and lows for each month in Formosa (°C, full record since 1940): January 33°/23°, February 32°/22°, March 30°/21°, April 27°/18°, May 24°/15°, June 22°/13°, July 22°/13°, August 24°/14°, September 26°/15°, October 28°/18°, November 30°/20°, December 32°/22°.
What is the weather like in Formosa in summer?
Summer in Formosa (December to February) is wet and hot. Expect 32–33°C by day and 22–23°C at night, with January the warmest month. Rain falls on about 10 days a month, adding up to around 151 mm.
What is the weather like in Formosa in winter?
June to August is winter in Formosa, and it is pleasantly warm. Daytime highs sit at 22–24°C and nights at 13–14°C; July is the coldest month. Rain is steady at around 84 mm a month, spread over roughly 6 days. It is the driest season of the year.
What is the weather like in Formosa in spring?
In spring, September through November, Formosa is wet and warm. September starts at 26°C by day and 15°C at night; by November it is 30°C and 20°C. Rain falls on about 9 days a month, adding up to around 160 mm.
What is the weather like in Formosa in autumn?
March to May is autumn in Formosa, and it is wet and warm. March is still 30°C by day and 21°C at night; by May it is down to 24°C and 15°C. Rain is steady at around 140 mm a month, spread over roughly 8 days.
How many days a year does it rain in Formosa?
On long-term average, Formosa has about 101 days a year with at least 2 mm of rain or snow. The annual total is roughly 1,605 mm.

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