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WEATHER LAB | How hot is it really during the Iowa State Fair?

Believe it or not, it has only been 100° or higher six times during the Iowa State Fair, and those six days all occurred in the same year.

DES MOINES, Iowa — For most states, August signals the unofficial end of summer and often the beginning of a new school year for students. 

Of course, kids head back to school in August in Iowa as well, but most Iowans would argue there's an event far more important during that timeframe: the great Iowa State Fair.

Ask any Iowan about what to expect at the Iowa State Fair, and they will usually mention things like fried foods, livestock and plenty of Iowa summer heat.

Heat and the Iowa State Fair have almost become synonymous with each other, but is it really that hot during the fair each year? Or is it just our perception? 

Although the fair is typically on the warmer end of the spectrum (it is mid-August in Iowa after all), it's not necessarily a scorcher all the time. 

In fact, records and climatological data show us some years have been cooler than average, like the Iowa State Fair of 1885, which boasted an average temperature of only 57.1°.

More recently, in 2004, the average temperature during the Iowa State Fair was only 65.3°.

Why assessing past weather during the Iowa State Fair is tricky

The Iowa State Fair is a 167-year-old tradition in the state.

According to the Iowa State Fair's website, the first statewide fair was held October 25-27, 1854 in Fairfield, Iowa.

Believe it or not, the first fair was held prior to America's major westward expansion.

The fair was held in various places around Iowa until 1886, when it found a permanent home on the east side of Des Moines. 

Reliable weather records in Des Moines date back to 1878, but this data can only offer insight into Iowa State Fair weather from 1886 onward.

Additionally, the fair has changed dates in its past.

The National Weather Service in Des Moines says the Iowa State Fair was held in September prior to 1900.

Since then, the fair has moved was held earlier and earlier, and now occurs in the middle of August each year. 

This skews the climatological data some, as the temperatures were generally cooler at the Iowa State Fair because it occurred in September, but then warmed some after 1900 due its move to mid-August.

Finally, the data is not entirely reliable since the Iowa State Fair was not held in 1898, 1942-1945 (during World War II), and most recently, 2020.

Still, the past weather data can give us a decent idea of what the weather is historically like during the Iowa State Fair.

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Temperatures at the Iowa State Fair

30-year averages from 1981 to 2010 show the average high temperature during the Iowa State Fair was 82.7°, while the average low temperature was 63.8°.

When it comes to high temperatures at the Iowa State Fair, the average high each decade since the 1890s has ranged between 80° and 86°, while the average low each decade since the 1890s has ranged between 57° and 65°.

The warmest fair on record boasted an average of 84.4° in 1983, while the fair of 1885 was the coolest with an average of 57.1°.

But remember, pre-1900 fairs were held in the fall.

Believe it or not, 1983 was also the only year in which 100°+ temperatures were recorded during the Iowa State Fair.  

Six days of the 1983 Iowa State Fair had high temperatures at or above 100°. 

August 16, 1983 experienced a high of 108°, making it the hottest day at any Iowa State Fair in recorded history.

On the flip side, September 7, 1885 was the coolest high temperature in Iowa State Fair history at only 57°. 

The coolest overnight low during a fair occurred on September 1, 1949, when the temperature dropped to 38°. 

Finally, in 2014, the first day of the Iowa State Fair (August 7, 2014) only had a high temperature of 71°.

Put simply: the hot weather may stick out more in Iowa State Fair memory, but it is not necessarily hot all the time. In fact, it is indeed cool some years, too. 

RELATED: Over 60 new foods announced for Iowa State Fair 2021

Rainfall at the Iowa State Fair

Only two Iowa State Fairs can be classified as totally dry with no measurable rainfall: 1893 and 1939.

1899, 1913, 1933, 1983, and 1986 all reported just a trace of rain, however.

The 1977 Iowa State Fair comes in at the wettest fair, with 8.46" of rain recorded during the fair.

That particular fair featured two incredibly wet days, with 4.18" of rain recorded on August 26, 1977, and 2.29" of rain the next day, on August 27, 1977.

From 1981 to 2010, the 30 year-average rainfall during the Iowa State Fair was 1.57". 

The data highlighted in this article was shared in partnership with the National Weather Service in Des Moines.


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