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Nishio weather by month: averages, rainfall & climate trends

Nishio has well-marked seasons, with 19.9°C between its warmest and coolest monthly means. Rainfall leans toward the stretch from May to October. Nishio weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

+4.1°Chigh well above average

26° / 17°Today
22° / 18°Average
see today in detail →

How it's changed

+1.7°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–490frost days a year now (2016–2025) · 1 in the 1940sfrost days a year · 1 in the 1940s14days above 30°C a year now (2016–2025) · 1 in the 1940sdays above 30°C · 1 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 70 mmhigh 9°low 5°February, rain 78 mmhigh 9°low 5°March, rain 112 mmhigh 12°low 7°April, rain 136 mmhigh 16°low 12°May, rain 162 mmhigh 20°low 16°June, rain 224 mmhigh 23°low 20°July, rain 187 mmhigh 27°low 24°August, rain 145 mmhigh 28°low 25°September, rain 212 mmhigh 26°low 22°October, rain 181 mmhigh 21°low 17°November, rain 98 mmhigh 16°low 12°December, rain 67 mmhigh 11°low 7°wettest month June, 224 mm · 1,671 mm a yearsee month by month →

Right now

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

Right now

18.1°

20°feels like
85%humidity
16°dew point
3 km/hfrom N
UV index0.5
sunrise05:52sunset17:25day length11h 33m
FriPartly cloudy26°17°
SatPartly cloudy26°18°
SunClear27°17°
MonClear27°18°
TuePartly cloudy25°19°
WedPartly cloudy26°20°
ThuOvercast25°16°

On this date: October 8

Today (forecast)
26° / 17°
Average for October 8
22° / 18°

High well above average · +4.1°C

  • Record high: 25.6° · 2025
  • Record low: 13.6° · 1997
  • One year ago: 26° / 23°

Every October 8 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 8 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 Nishio is sampled from the ECMWF ERA5 reanalysis at 34.87°N, 137.05°E, with daily records since 1940.

Coordinates
34.87°N, 137.05°E
Time zone
Asia/Tokyo
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

24 of the last 31 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

The year peaks in August, at around 28.1°C by mid-afternoon, with nights around 25.2°C. Around 120 nights a year stay above 20°C. At the other extreme, January brings afternoon highs of about 8.9°C and typical overnight lows of 4.7°C. Freezing temperatures almost never occur.

The yearly total for Nishio comes to about 1,671 mm; monthly amounts range from 67 mm in December up to 224 mm in June.

The record here starts in 1940, and since then the annual mean in Nishio has climbed 1.7°C from the first ten years to the last ten. Days above 30°C have grown noticeably more frequent, from around 1 a year in the first decade to about 14 in the last.

Climate graph (climograph)

August is the warmest month, January the coolest: a yearly swing of 20°C. Wettest month: June (~224 mm). Whole year averages ~1,671 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 111 rainy days a year: most in September (~12), fewest in December (~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.

Nishio 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 lowRainRainy daysDaylightRecord highRecord low
January8.9°4.7°70 mm79.9 h17.5° (1990)−1.2° (1997)
February9.3°4.7°78 mm710.7 h17.9° (1993)−1.2° (1942)
March12.1°7.1°112 mm911.7 h19.9° (2018)0.3° (1977)
April16.2°11.8°136 mm912.9 h24.6° (1973)4.1° (1972)
May19.8°16.1°162 mm913.8 h27.4° (2015)8.5° (1991)
June23.1°20.1°224 mm1214.3 h31.2° (2022)13.9° (1969)
July26.6°24.0°187 mm1114.1 h33.0° (2018)16.8° (1966)
August28.1°25.2°145 mm1113.3 h33.5° (1994)20.0° (1956)
September25.7°22.3°212 mm1212.2 h31.9° (2010)14.5° (1992)
October21.0°17.0°181 mm1011.1 h28.3° (2024)9.8° (1943)
November16.3°12.0°98 mm710.1 h25.2° (2000)4.3° (1970)
December11.4°7.2°67 mm69.7 h22.0° (2004)1.4° (1947)

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: +0.18°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

Jun–Aug is warming fastest: +0.20°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: 0.8 early in the record → 13.8 recently. Frost days: 1 → 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 1994, all-time low in 1942: 33.5°C / −1.2°C.

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

Annual rainfall

~1,671 mm/year on average. Last decade: +5% vs that average. Long-term trend: +24 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 Nishio

Which is the warmest month in Nishio?
On long-term average, the warmest month in Nishio is August (mean daily temperature of about 26.6°C) and the coolest is January (about 6.7°C).
How does today's temperature in Nishio compare to the historical average?
On October 8, 2026, Nishio is forecast to reach a high of 26.0°C and a low of 17.2°C. The long-term average for this date (the full record since 1940) is a high of 21.9°C and a low of 18.2°C, so today's high is 4.1°C warmer than that average.
How much has Nishio warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Nishio is about 1.7°C warmer.
How much does it rain in Nishio?
Nishio receives about 1,671 mm of precipitation per year on long-term average, with June typically the wettest month.
What is the average temperature in Nishio?
Over the full record (since 1940), the annual mean temperature in Nishio is about 16.3°C. The warmest month is August and the coolest is January.
What are the average temperatures in Nishio by month?
Average daily highs and lows for each month in Nishio (°C, full record since 1940): January 9°/5°, February 9°/5°, March 12°/7°, April 16°/12°, May 20°/16°, June 23°/20°, July 27°/24°, August 28°/25°, September 26°/22°, October 21°/17°, November 16°/12°, December 11°/7°.
What is the weather like in Nishio in summer?
June to August is summer in Nishio, and it is wet and pleasantly warm. It warms from 23°C by day and 20°C at night in June to 28°C and 25°C in August. Rain falls off from 224 mm on 12 days in June to 145 mm on 11 days in August.
What is the weather like in Nishio in winter?
In winter, December through February, Nishio is on the cool side. Afternoons run 9–11°C and nights 5–7°C; February is the coldest month. Rain is steady at around 71 mm a month, spread over roughly 7 days. No season is drier.
What is the weather like in Nishio in spring?
Spring in Nishio (March to May) is wet and fairly mild. March is still 12°C in the afternoon and 7°C at night, May already 20°C and 16°C. Rain falls on about 9 days a month, adding up to around 137 mm.
What is the weather like in Nishio in autumn?
In autumn, September through November, Nishio is wet and mild. September is still 26°C by day and 22°C at night; by November it is down to 16°C and 12°C. Rain eases through the season: 12 rainy days and 212 mm in September, 7 days and 98 mm in November.
How many days a year does it rain in Nishio?
On long-term average, Nishio has about 111 days a year with at least 2 mm of rain or snow. The annual total is roughly 1,671 mm.

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