Decorah (IA) Temperature by Month
The average annual maximum temperature in Decorah, Iowa, United States of America is 14°C (57°F), with daytime highs ranging from -3°C (27°F) in January to 28°C (82°F) in July. This page covers monthly averages, day-night differences, and how Decorah compares to cities worldwide.
Decorah Monthly Temperatures
In Decorah, temperatures can shift dramatically between warm in summer and very cold in winter. Nights follow the same pattern, with lows ranging from 16°C (61°F) in July to -13°C (9°F) in January.
The chart below illustrates the average maximum day and minimum night temperatures in Decorah by month:
Low temperatures are most often recorded between 4 AM and 6 AM, while highs typically occur around 3 PM.
The chart below shows the average temperature throughout the year:
Temperature: Decorah 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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Decorah vs World: Temperature Compared
Decorah's average annual maximum temperature is 14°C (57°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.
Interlaken, Switzerland averages 8°C (46°F) a year, with cold winters and cool summers thanks to its Alpine setting.
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.
What Does the Temperature Feel Like in Decorah?
Temperature alone doesn't tell the whole story — humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.
In the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.
In Decorah, January is the coolest month, with average highs of -3°C (27°F) and humidity around 71% — considered high. In July, the warmest month, temperatures average 28°C (82°F) with 71% humidity — conditions that feel high. For a full picture, see our humidity page.
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 Decorah's weather — including monthly rainfall, sunshine hours, and humidity — visit our Decorah climate page.
