Spring has finally sprung, and while the veggies might not be in the ground (I’m eying you, Natorps), the weather has certainly turned. Yet every year, I feel like I’m faked-out by a series of days tricking me into thinking it’s spring, way earlier than it should.
It’s a known phenomenon called “Fake Spring,” and I wanted to know whether there is any scientific evidence behind this trend, or if it was just created by a bunch of depressed Ohioans in the middle of winter.
Methodology
So first, let’s talk about our output. I had a couple of ideas to quantify what a “fake spring” could be. I had two major ideas…
- X Days with average temperatures over YY
- X Days with average temperatures significantly over the average in the same period, in different years.
Because I want to make my life complex, I chose option 2, primarily because the temperature would be more likely to be higher, closer to actual spring, which would likely give us some artificial false-positives later in winter.
In plain English, if the average temperature in Dayton, Ohio, from January 1st to January 7th every year is 30 degrees, but in 2020, it was 60 degrees, I would classify that as “fake spring.” I considered using the week number, but chaotic weather doesn’t follow a calendar, so I calculated a rolling 7-day average for each day instead. This is not perfect, as one super-hot day could skew the results.
Results
Fake spring is a thing! And it’s relatively common in Dayton, Ohio, occurring 16 times in the last 24 years. The most springy fake spring happened from Jan 20th 2017 -> Jan 27th 2017, with an average temperature 72% above the expected, at 44 degrees.
Stay curious!
Sources
Climate Data Online (CDO) – The National Climatic Data Center’s (NCDC) Climate Data Online (CDO) provides free access to NCDC’s archive of historical weather and climate data in addition to station history information. | National Climatic Data Center (NCDC). n.d. Retrieved April 16, 2026. https://www.ncei.noaa.gov/cdo-web/.
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