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Tainan weather by month: averages, rainfall & climate trends

Average temperatures in Tainan follow a clear seasonal rhythm, rising and falling by 10.7°C over the course of the year. Rainfall is strongly seasonal: the bulk of the year's rain falls between May and September. Tainan weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

+2.3°Chigh above average

31° / 26°Today
28° / 22°Average
see today in detail →

How it's changed

+1.7°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–49133days above 30°C a year now (2016–2025) · 44 in the 1940sdays above 30°C · 44 in the 1940s+1.7°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 48 mmhigh 21°low 15°February, rain 52 mmhigh 22°low 15°March, rain 65 mmhigh 25°low 18°April, rain 108 mmhigh 27°low 21°May, rain 281 mmhigh 29°low 24°June, rain 386 mmhigh 30°low 25°July, rain 296 mmhigh 31°low 26°August, rain 378 mmhigh 30°low 25°September, rain 197 mmhigh 30°low 25°October, rain 65 mmhigh 29°low 23°November, rain 41 mmhigh 26°low 20°December, rain 43 mmhigh 23°low 16°wettest month June, 386 mm · 1,960 mm a yearsee month by month →

Right now

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

Right now

30.6°

34°feels like
62%humidity
23°dew point
15 km/hfrom NW
UV index3.8
sunrise05:57sunset17:31day length11h 34m
TodayMostly clear31°26°
MonMostly clear31°25°
TueMostly clear31°25°
WedMostly clear31°25°
ThuOvercast29°23°
FriOvercast29°23°
SatOvercast28°25°

On this date: October 18

Today (forecast)
31° / 26°
Average for October 18
28° / 22°

High above average · +2.3°C

  • Record high: 32.5° · 2025
  • Record low: 18.1° · 1947
  • One year ago: 33° / 26°

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 Tainan is sampled from the ECMWF ERA5 reanalysis at 22.99°N, 120.21°E, with daily records since 1940.

Coordinates
22.99°N, 120.21°E
Time zone
Asia/Taipei
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: +1.5°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 July, at around 30.9°C by mid-afternoon, with nights around 25.6°C. On about 245 nights a year, the temperature never drops below 20°C. The coolest month is January, when afternoons reach about 21.4°C and overnight lows sit around 14.6°C. Freezing temperatures almost never occur.

In total, Tainan averages about 1,960 mm of precipitation a year; June is usually the wettest month (386 mm) and November the driest (41 mm).

Over the full record (since 1940), the annual mean temperature in Tainan has risen by 1.7°C between its first decade and its last. The count of days past 30°C has risen from roughly 45 a year to 135 between the record's first and last decades.

Climate graph (climograph)

July is the warmest month, January the coolest: a yearly swing of 11°C. Wettest month: June (~386 mm). Whole year averages ~1,960 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.

Tainan 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
January21.4°14.6°48 mm10.7 h28.2° (1969)5.7° (1970)
February22.2°15.4°52 mm11.2 h30.5° (2009)6.8° (1958)
March24.5°17.8°65 mm11.8 h31.6° (2010)8.0° (1986)
April27.3°21.1°108 mm12.5 h32.5° (1976)10.8° (1969)
May29.3°23.7°281 mm13.1 h34.6° (1963)18.3° (1971)
June30.1°25.1°386 mm13.4 h35.6° (1991)19.5° (1964)
July30.9°25.6°296 mm13.3 h35.6° (1962)22.7° (1966)
August30.4°25.3°378 mm12.8 h33.7° (1983)21.9° (1941)
September30.1°24.7°197 mm12.1 h34.6° (2014)18.4° (1966)
October28.5°22.6°65 mm11.5 h33.3° (2017)15.3° (1978)
November26.0°19.8°41 mm10.9 h31.7° (1972)11.4° (1988)
December22.8°16.3°43 mm10.6 h29.8° (2018)7.5° (1973)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +1.7°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: +0.21°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: +0.25°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: 44.0 early in the record → 132.6 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 1962, all-time low in 1970: 35.6°C / 5.7°C.

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

Annual rainfall

~1,960 mm/year on average. Last decade: +5% 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 Tainan

Which is the warmest month in Tainan?
On long-term average, the warmest month in Tainan is July (mean daily temperature of about 28.0°C) and the coolest is January (about 17.4°C).
How does today's temperature in Tainan compare to the historical average?
On October 18, 2026, Tainan is forecast to reach a high of 30.8°C and a low of 25.8°C. The long-term average for this date (the full record since 1940) is a high of 28.5°C and a low of 22.4°C, so today's high is 2.3°C warmer than that average.
How much has Tainan warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Tainan is about 1.7°C warmer.
How much does it rain in Tainan?
Tainan receives about 1,960 mm of precipitation per year on long-term average, with June typically the wettest month.
What is the average temperature in Tainan?
Over the full record (since 1940), the annual mean temperature in Tainan is about 23.6°C. The warmest month is July and the coolest is January.
What are the average temperatures in Tainan by month?
Average daily highs and lows for each month in Tainan (°C, full record since 1940): January 21°/15°, February 22°/15°, March 25°/18°, April 27°/21°, May 29°/24°, June 30°/25°, July 31°/26°, August 30°/25°, September 30°/25°, October 29°/23°, November 26°/20°, December 23°/16°.
What is the weather like in Tainan in summer?
Summer in Tainan (June to August) is wet and hot. Afternoons run 30–31°C and nights 25–26°C; July is the warmest month. About 354 mm of rain a month. No season is wetter.
What is the weather like in Tainan in winter?
Winter in Tainan (December to February) is pleasantly warm. Expect 21–23°C by day and 15–16°C at night, with January the coldest month. Rain is steady at around 48 mm a month. No season is drier.
What is the weather like in Tainan in spring?
March to May is spring in Tainan, and it is wet and warm. March starts at 25°C by day and 18°C at night; by May it is 29°C and 24°C. Rain picks up through the season, 65 mm in March to 281 mm in May.
What is the weather like in Tainan in autumn?
Autumn in Tainan (September to November) is wet and warm. September is still 30°C by day and 25°C at night; by November it is down to 26°C and 20°C. Rain falls off from 197 mm in September to 41 mm in November.

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