
Farmers around North Judson, Ind., went 40 days without rain — not even a trace. No rain was recorded from Aug. 10 until Sept. 18. Does that sound about right?
Given the super-dry late summer and early fall across most of the Corn Belt in 2024, you probably wouldn’t question that report. Except it wasn’t recorded in 2024. That 40-day stretch was in 2017 and is the current longest streak on record without measurable precipitation or a trace of precipitation for the cooperating National Oceanic and Atmospheric Administration weather station in North Judson.
“We get questions like this a lot, especially when we have extended spells of weather — too dry or too wet — like we have seen recently,” says Beth Hall, head of the Midwestern Regional Climate Center and Indiana state climatologist. “Just because we have a long stretch of dry, hot or cold weather doesn’t necessarily mean we are setting records.”
Melissa Widhalm, a regional climatologist at the center, notes that when rainy days were few and far between in late summer and early fall, people began asking questions such as, “What’s the longest we have ever gone without rain?”
The questions may seem straightforward, but “the devil is in the details,” Widhalm says. Rainfall is measured to the nearest one-hundredth of an inch, but sometimes less than 0.01 inch may fall. It’s not bone-dry, but it’s not quite “measurable” either. Weather observers report this as a “trace,” she says.
If you count days between rainfall events, are trace values streak-breakers?
Different data analysis tools may handle trace measurements differently. If you see two datasets with different counts for dry streak records, they’re probably not dealing with trace measurements the same, Widhalm explains.
Weather streak tool
The National Weather Service maintains the U.S. Streaks tool that anyone can use. It allows you to find all kinds of streaks for existing NOAA weather stations.
This tool lets you select “no precipitation” or “no measurable precipitation” as a data filter option, Widhalm explains. In the U.S. Streaks tool, trace observations break the streak if you select “no precipitation,” whereas trace observations are treated like zero-inch measurements and don’t break the streak if you select “no measurable precipitation.”
Does this difference matter? The longest streak for days with no precipitation, not even a trace, for farmers around Chalmers, Ind., was not set in 2024, but in 2023, from Aug. 19 to Sept. 6. However, the longest streak without measurable precipitation, which allows trace amounts, occurred in 2015, from Oct. 4 to Oct. 27.
You also can use the tool to determine streaks for a variety of precipitation values, warm or cold temperature measurements, and even above or below normal temperatures. You can check on streaks no matter where you live in the U.S.
Study the tables below to see various streaks on record from around the Midwest.
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