Iowa City (IA) Temperature by Month

Iowa City in Iowa, United States of America sees significant seasonal temperature differences, with daytime highs between -1°C (30°F) in January and 29°C (84°F) in July, averaging 16°C (61°F) annually. Explore the full monthly breakdown below.

The climate in Iowa City is dynamic, ranging widely from very cold in winter to comfortable in summer. Nights are significantly colder, with lows dropping from 18°C (64°F) in July to -11°C (12°F) in January.

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

The minimum temperature is often recorded between 4 AM and 6 AM, while the highest temperature is usually reached at 3 PM, when the sun's heating effect is strongest.

The chart below shows the average temperature throughout the year:

Iowa City'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:

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

Zermatt, Switzerland averages just 4°C (39°F) annually due to its altitude, with very cold winters and cool summers even at its warmest.

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

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

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 Iowa City's weather, including monthly rainfall, sunshine hours, and humidity, visit our Iowa City climate page.