Ottumwa (IA) Temperature by Month

The average annual maximum temperature in Ottumwa, Iowa, United States of America is 16°C (61°F), with daytime highs ranging from 0°C (32°F) in January to 30°C (86°F) in July. This page covers monthly averages, day-night differences, and how Ottumwa compares to cities worldwide.

The weather in Ottumwa experiences significant differences between warm and cold seasons, with big shifts in temperature. At night, minimum temperatures range from 18°C (64°F) in July to -10°C (14°F) in January.

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

The coldest point of the day usually falls between 4 AM and 6 AM, with temperatures peaking around 3 PM.

The chart below shows the average temperature throughout the year:

Ottumwa's average annual maximum temperature is 16°C (61°F). To put that in context, here's how it compares to a few well-known destinations:

Lisbon, Portugal averages 21°C (70°F) annually, warm summers, mild winters, and rain mainly in the cooler months.

Glasgow, Scotland averages 13°C (55°F) a year, mild but often grey, with cold winters and rarely hot summers.

Osaka, Japan averages 22°C (72°F) annually, with hot humid summers, mild winters, and pleasant spring and autumn seasons.

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.

Whether a city sits on the coast or deep inland makes a significant difference to its climate. Coastal areas tend to have more stable temperatures year-round, large bodies of water absorb heat slowly in summer and release it gradually in winter, keeping extremes in check. Cities far from the sea don't benefit from that buffer, which is why continental climates tend to have hotter summers and colder winters than their coastal counterparts at the same latitude.

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