Sioux City (IA) Temperature by Month
The average annual maximum temperature in Sioux City, Iowa, United States of America is 16°C (61°F), with daytime highs ranging from -1°C (30°F) in January to 30°C (86°F) in July. This page covers monthly averages, day-night differences, and how Sioux City compares to cities worldwide.
Sioux City Monthly Temperatures
Visitors to Sioux City 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 Sioux City 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:
Temperature: Sioux City vs the United States of America
The map below shows the annual temperature across the United States of America. You can also select individual months if you want to compare a specific time of year.
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Sioux City vs World: Temperature Compared
Sioux 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:
Lisbon, Portugal averages 21°C (70°F) annually — warm summers, mild winters, and rain mainly in the cooler months.
Toronto, Canada averages 13°C (55°F) annually, with cold snowy winters balanced by genuinely warm summers.
Buenos Aires, Argentina averages 23°C (73°F) a year, with hot summers and mild winters — and seasons reversed compared to Europe.
Melbourne, Australia averages 20°C (68°F) annually — known for unpredictable weather, with four seasons sometimes happening in one day.
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.
For cities and regions with significant elevation, altitude is one of the biggest factors shaping local temperatures. As a rule of thumb, temperatures fall by around 6°C for every 1,000 metres gained — so a city at 2,000 metres will typically be around 12°C cooler than a city at sea level in the same region. Higher ground also tends to see more dramatic day-to-night temperature swings, since thinner air loses heat faster after sunset.
For more on Sioux City's weather — including monthly rainfall, sunshine hours, and humidity — visit our Sioux City climate page.
