Marshalltown (IA) Temperature by Month

The average annual maximum temperature in Marshalltown, Iowa, United States of America is 15°C (59°F), with daytime highs ranging from -3°C (27°F) in January to 29°C (84°F) in July. This page covers monthly averages, day-night differences, and how Marshalltown compares to cities worldwide.

Visitors to Marshalltown can expect significant temperature changes throughout the year. Nighttime temperatures also vary widely, ranging from 17°C (63°F) in July to -13°C (9°F) in January.

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

From around 4 AM to 6 AM temperatures are at their lowest; by 3 PM they've climbed to their daily peak.

The chart below shows the average temperature throughout the year:

Marshalltown's average annual maximum temperature is 15°C (59°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.

Toronto, Canada averages 13°C (55°F) annually, with cold snowy winters balanced by genuinely warm summers.

Chicago, USA averages 15°C (59°F) annually, known for extreme seasonal swings, from bitterly cold winters to warm summers.

Perth, Australia averages 25°C (77°F) annually, with a classic Mediterranean climate, hot dry summers and mild wet winters.

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