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Yokosuka weather by month: averages, rainfall & climate trends

Yokosuka has well-marked seasons, with 18.3°C between its warmest and coolest monthly means. The heaviest rain tends to come in September and October. Yokosuka weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.

Today vs average

+6.2°Chigh well above average

26° / 24°Today
20° / 17°Average
see today in detail →

How it's changed

+1.6°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4984days above 25°C a year now (2016–2025) · 58 in the 1940sdays above 25°C · 58 in the 1940s+1.6°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 73 mmhigh 10°low 5°February, rain 86 mmhigh 10°low 5°March, rain 134 mmhigh 12°low 8°April, rain 131 mmhigh 16°low 12°May, rain 148 mmhigh 19°low 17°June, rain 185 mmhigh 22°low 20°July, rain 137 mmhigh 25°low 23°August, rain 123 mmhigh 27°low 25°September, rain 184 mmhigh 25°low 22°October, rain 204 mmhigh 21°low 17°November, rain 119 mmhigh 16°low 13°December, rain 69 mmhigh 12°low 8°wettest month October, 204 mm · 1,593 mm a yearsee month by month →

Right now

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

Right now

26.2°

28°feels like
79%humidity
22°dew point
26 km/hfrom SW
UV index3.9
sunrise05:51sunset17:00day length11h 09m
TodayOvercast26°24°
WedOvercast27°24°
ThuOvercast25°19°
FriOvercast19°17°
SatLight rain19°16°
SunOvercast21°19°
MonLight rain22°20°

On this date: October 20

Today (forecast)
26° / 24°
Average for October 20
20° / 17°

High well above average · +6.2°C

  • Highest since 1940: 24.3° · 2004
  • Lowest since 1940: 12.7° · 1986
  • One year ago: 20° / 15°

Every October 20 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 20 on record (n = 86). 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 Yokosuka is sampled from the ECMWF ERA5 reanalysis at 35.28°N, 139.67°E, with daily records since 1940.

Coordinates
35.28°N, 139.67°E
Time zone
Asia/Tokyo
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

24 of the last 30 days were warmer than the historical average for that date. Average difference: +1.3°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 August, at around 27.0°C by mid-afternoon, with nights around 24.8°C. On about 120 nights a year, the temperature never drops below 20°C. The coolest month is February, when afternoons reach about 9.6°C and overnight lows sit around 5.2°C. Frost is essentially unknown.

Yokosuka picks up roughly 1,593 mm a year, with a peak of 204 mm in October and as little as 69 mm in December.

Comparing the record's first decade with its most recent one, Yokosuka now averages 1.6°C warmer than it did in the 1940s. Days above 25°C have grown noticeably more frequent, from around 60 a year in the first decade to about 85 in the last.

Climate graph (climograph)

August is the warmest month, February the coolest: a yearly swing of 18°C. Wettest month: October (~204 mm). Whole year averages ~1,593 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 114 rainy days a year: most in September (~12), fewest in January (~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.

Yokosuka 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
January9.5°5.3°73 mm69.9 h18.1° (1969)−0.5° (1997)
February9.6°5.2°86 mm710.7 h18.3° (1962)−0.4° (1952)
March12.1°7.7°134 mm1111.7 h20.0° (2023)1.6° (1970)
April15.9°12.4°131 mm1012.9 h21.3° (1977)4.6° (1987)
May19.2°16.6°148 mm1013.9 h24.0° (2022)9.4° (1953)
June22.0°19.9°185 mm1214.4 h27.5° (2025)13.8° (1958)
July25.1°23.1°137 mm1014.2 h30.3° (2025)16.3° (1976)
August27.0°24.8°123 mm1013.3 h31.8° (2020)19.6° (2003)
September24.9°22.2°184 mm1212.2 h30.3° (2023)15.7° (2001)
October20.5°17.3°204 mm1111.1 h27.1° (2016)10.4° (1983)
November16.4°12.6°119 mm910.1 h23.5° (2023)4.3° (2016)
December12.1°8.0°69 mm69.6 h22.6° (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 +1.6°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: +0.16°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: +0.16°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: 57.8 early in the record → 83.9 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 1997: 31.8°C / −0.5°C.

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

Annual rainfall

~1,593 mm/year on average. Last decade: +3% vs that average. Long-term trend: +39 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 Yokosuka

Which is the warmest month in Yokosuka?
On long-term average, the warmest month in Yokosuka is August (mean daily temperature of about 25.8°C) and the coolest is February (about 7.5°C).
How does today's temperature in Yokosuka compare to the historical average?
On October 20, 2026, Yokosuka is forecast to reach a high of 26.2°C and a low of 23.9°C. The long-term average for this date (the full record since 1940) is a high of 20.0°C and a low of 16.5°C, so today's high is 6.2°C warmer than that average.
How much has Yokosuka warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Yokosuka is about 1.6°C warmer.
How much does it rain in Yokosuka?
Yokosuka receives about 1,593 mm of precipitation per year on long-term average, with October typically the wettest month.
What is the average temperature in Yokosuka?
Over the full record (since 1940), the annual mean temperature in Yokosuka is about 16.3°C. The warmest month is August and the coolest is February.
What are the average temperatures in Yokosuka by month?
Average daily highs and lows for each month in Yokosuka (°C, full record since 1940): January 10°/5°, February 10°/5°, March 12°/8°, April 16°/12°, May 19°/17°, June 22°/20°, July 25°/23°, August 27°/25°, September 25°/22°, October 21°/17°, November 16°/13°, December 12°/8°.
What is the weather like in Yokosuka in summer?
Summer in Yokosuka (June to August) is wet and pleasantly warm. June starts at 22°C by day and 20°C at night; by August it is 27°C and 25°C. Rain falls off from 185 mm on 12 days in June to 123 mm on 10 days in August.
What is the weather like in Yokosuka in winter?
Winter in Yokosuka (December to February) is on the cool side. Daytime highs sit at 10–12°C and nights at 5–8°C; February is the coldest month. Rain falls on about 7 days a month, adding up to around 76 mm. It is the driest season of the year.
What is the weather like in Yokosuka in spring?
In spring, March through May, Yokosuka is wet and fairly mild. It warms from 12°C by day and 8°C at night in March to 19°C and 17°C in May. Rain is steady at around 138 mm a month, spread over roughly 10 days.
What is the weather like in Yokosuka in autumn?
Autumn in Yokosuka (September to November) is wet and mild. It cools from 25°C by day and 22°C at night in September to 16°C and 13°C in November. Rain eases through the season: 12 rainy days and 184 mm in September, 9 days and 119 mm in November.
How many days a year does it rain in Yokosuka?
On long-term average, Yokosuka has about 114 days a year with at least 2 mm of rain or snow. The annual total is roughly 1,593 mm.

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