Oshima Temperature by Month

The average annual maximum temperature in Oshima, Tokyo Prefecture, Japan is 20°C (68°F), with daytime highs ranging from 12°C (54°F) in January to 28°C (82°F) in August. This page covers monthly averages, day-night differences, and how Oshima compares to cities worldwide.

With significant temperature fluctuations, Oshima enjoys distinct seasons year-round. Nighttime lows range from 25°C (77°F) in August to 8°C (46°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in Oshima by month:

Temperatures tend to bottom out between 4 AM and 6 AM, then climb to their daily peak around 3 PM.

The chart below shows the average temperature throughout the year:

Oshima's average annual maximum temperature is 20°C (68°F). To put that in context, here's how it compares to a few well-known destinations:

Athens, Greece sits at 23°C (73°F) on average, with hot dry summers and mild winters characteristic of the Mediterranean.

On the cooler end, Oslo, Norway averages just 10°C (50°F) annually, with pleasant summers but long, cold winters.

Boston, USA averages 16°C (61°F) annually, with four distinct seasons and cold winters that rival northern Europe.

Brisbane, Australia averages 26°C (79°F) a year, with warm winters and hot, humid summers.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Seasonal temperature shifts influence more than just how warm it feels, they also drive changes in rainfall, cloud cover, and wind patterns throughout the year.

Warmer air holds more moisture, which tends to mean heavier or more frequent rain during the warmer months. When temperatures drop in winter, any precipitation that does fall is more likely to come as snow or sleet, though in Oshima this rarely lasts long on the ground.

For more on Oshima's weather, including monthly rainfall, sunshine hours, and humidity, visit our Oshima climate page.