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Ichinomiya weather by month: averages, rainfall & climate trends

Ichinomiya swings through a wide annual range, with 23.4°C between the monthly means of its warmest and coldest months. The heavier rain months run from May to October. Ichinomiya weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.

Today vs average

+3.6°Chigh well above average

25° / 20°Today
22° / 13°Average
see today in detail →

How it's changed

+3.2°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4922frost days a year now (2016–2025) · 79 in the 1940sfrost days a year · 79 in the 1940s74days above 30°C a year now (2016–2025) · 30 in the 1940sdays above 30°C · 30 in the 1940s+3.2°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 59 mmhigh 9°low 0°February, rain 73 mmhigh 10°low 1°March, rain 120 mmhigh 13°low 3°April, rain 155 mmhigh 19°low 9°May, rain 179 mmhigh 23°low 14°June, rain 258 mmhigh 27°low 19°July, rain 303 mmhigh 30°low 23°August, rain 224 mmhigh 32°low 24°September, rain 266 mmhigh 28°low 20°October, rain 170 mmhigh 22°low 13°November, rain 97 mmhigh 17°low 7°December, rain 62 mmhigh 11°low 2°wettest month July, 303 mm · 1,966 mm a yearsee month by month →

Right now

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

Right now

20.6°

23°feels like
88%humidity
19°dew point
3 km/hfrom N
UV index0.0
sunrise06:03sunset17:12day length11h 09m
TueOvercast25°20°
WedOvercast29°19°
ThuPartly cloudy22°15°
FriOvercast20°14°
SatOvercast19°16°
SunOvercast21°19°
MonLight rain21°19°

On this date: October 19

Today (forecast)
25° / 20°
Average for October 19
22° / 13°

High well above average · +3.6°C

  • Highest since 1940: 27.8° · 1961
  • Lowest since 1940: 3.4° · 1986
  • One year ago: 23° / 19°

Every October 19 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 19 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 Ichinomiya is sampled from the ECMWF ERA5 reanalysis at 35.30°N, 136.80°E, with daily records since 1940.

Coordinates
35.30°N, 136.80°E
Time zone
Asia/Tokyo
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

26 of the last 31 days were warmer than the historical average for that date. Average difference: +2.2°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 warmest month is August, with typical afternoon highs of 31.6°C and nights around 23.9°C. Roughly 75 days a year now top 30°C. At the other extreme, January brings afternoon highs of about 8.7°C and typical overnight lows of 0.1°C.

The yearly total for Ichinomiya comes to about 1,966 mm; monthly amounts range from 59 mm in January up to 303 mm in July. Precipitation falls on roughly 123 days in a typical year.

The record here starts in 1940, and since then the annual mean in Ichinomiya has climbed 3.2°C from the first ten years to the last ten. Where the first decade averaged 80 frost days a year, the recent one saw about 20.

Climate graph (climograph)

August is the warmest month, January the coolest: a yearly swing of 23°C. Wettest month: July (~303 mm). Whole year averages ~1,966 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 123 rainy days a year: most in July (~17), fewest in January (~5).

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.

Ichinomiya 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
January8.7°0.1°59 mm59.9 h18.0° (2020)−7.4° (1981)
February9.6°0.5°73 mm610.7 h22.0° (2021)−12.0° (1968)
March13.4°3.5°120 mm911.7 h26.1° (1998)−4.4° (1984)
April19.0°9.0°155 mm1012.9 h29.2° (2004)−1.9° (1941)
May23.3°14.0°179 mm1113.9 h33.5° (1958)3.1° (1949)
June26.5°19.0°258 mm1514.4 h37.6° (2022)9.1° (1952)
July30.2°23.1°303 mm1714.2 h38.4° (2018)13.0° (1966)
August31.6°23.9°224 mm1513.3 h38.6° (1994)14.4° (1956)
September27.8°20.1°266 mm1412.2 h36.9° (1994)9.0° (1966)
October22.3°13.5°170 mm911.1 h31.8° (2024)2.9° (1983)
November16.7°7.4°97 mm710.1 h26.3° (2000)−1.6° (1948)
December11.2°2.3°62 mm59.6 h22.0° (2015)−6.2° (1981)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +3.2°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: +0.35°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: +0.37°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: 29.8 early in the record → 73.7 recently. Frost days: 79 → 22.

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 1994, coldest in 1968: 38.6°C / −12.0°C.

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

Annual rainfall

~1,966 mm/year on average. Last decade: +1% vs that average. Long-term trend: +9 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 Ichinomiya

Which is the warmest month in Ichinomiya?
On long-term average, the warmest month in Ichinomiya is August (mean daily temperature of about 27.3°C) and the coolest is January (about 3.9°C).
How does today's temperature in Ichinomiya compare to the historical average?
On October 19, 2026, Ichinomiya is forecast to reach a high of 25.4°C and a low of 20.4°C. The long-term average for this date (the full record since 1940) is a high of 21.8°C and a low of 12.7°C, so today's high is 3.6°C warmer than that average.
How much has Ichinomiya warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Ichinomiya is about 3.2°C warmer.
How much does it rain in Ichinomiya?
Ichinomiya receives about 1,966 mm of precipitation per year on long-term average, with July typically the wettest month.
What is the average temperature in Ichinomiya?
Over the full record (since 1940), the annual mean temperature in Ichinomiya is about 15.4°C. The warmest month is August and the coolest is January.
What are the average temperatures in Ichinomiya by month?
Average daily highs and lows for each month in Ichinomiya (°C, full record since 1940): January 9°/0°, February 10°/1°, March 13°/3°, April 19°/9°, May 23°/14°, June 27°/19°, July 30°/23°, August 32°/24°, September 28°/20°, October 22°/13°, November 17°/7°, December 11°/2°.
What is the weather like in Ichinomiya in summer?
June to August is summer in Ichinomiya, and it is wet and warm. It warms from 27°C by day and 19°C at night in June to 32°C and 24°C in August. Rain falls on about 16 days a month, adding up to around 262 mm. It is the wettest season of the year.
What is the weather like in Ichinomiya in winter?
December to February is winter in Ichinomiya, and it is on the cool side. Daytime highs sit at 9–11°C and nights at 0–2°C; January is the coldest month. Rain is steady at around 64 mm a month, spread over roughly 5 days. It is the driest season of the year.
What is the weather like in Ichinomiya in spring?
March to May is spring in Ichinomiya, and it is wet and mild. March is still 13°C in the afternoon and 3°C at night, May already 23°C and 14°C. Rain falls on about 10 days a month, adding up to around 152 mm.
What is the weather like in Ichinomiya in autumn?
Autumn in Ichinomiya (September to November) is wet and pleasantly warm. September is still 28°C by day and 20°C at night; by November it is down to 17°C and 7°C. Rain eases through the season: 14 rainy days and 266 mm in September, 7 days and 97 mm in November.
How many days a year does it rain in Ichinomiya?
On long-term average, Ichinomiya has about 123 days a year with at least 2 mm of rain or snow. The annual total is roughly 1,966 mm.

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