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Posted on September 23rd, 2025 in Drought, Wildlife | No Comments »

Purdue Landscape Report: The last week has caused many to struggle with whether to turn the heat on inside.  Mornings have been quite chilly, and I am guessing several readers may have also struggled with the decision to wear a jacket as they started their workday.  These are tough decisions, no doubt.  Several data sources have suggested we have had at least 2 weeks of consecutive below-average daily mean temperatures.  While not a record, this is certainly noticeable!  Perhaps we are hoping those tomato plants will produce just a few more tomatoes.  Is it mum season, already?  The good news – for those not quite ready to say goodbye to warm days, not needing coats, and garden delights – is warm temperatures are expected to return.  Daily high temperatures are already in the 80s and Indiana is likely to see temperatures in the mid-90s by next week.  There is significant confidence that this warmer-than-normal temperature trend is likely to continue through most of September.  Average high temperatures typically range from 75°F – 85°F in mid-September and 70°F – 75°F in late September, so keep in mind climate outlooks are all relative.  Indiana is not likely to experience triple-digit heat waves over the next few weeks, but nighttime low temperatures are likely to fight for temperatures warranting a sweater or jacket.


"Fig.
Figure 1. U.S. Drought Monitor status for conditions as of Tuesday, September 9, 2025 (Purdue Landscape Report)


Figure 2. Total precipitation amounts forecasted for September 11-18, 2025 (Purdue Landscape Report)

There’s been a noticeable lack of precipitation with Indiana receiving well below-normal precipitation throughout the state over the past 30 days except for the northwestern counties.  This has led to expansion of both Abnormally Dry (D0) and Moderate Drought (D1) areas across the state (Figure 1).  Unfortunately, both forecasts and climate outlooks suggest this below-normal precipitation pattern is likely to continue for a while.  Over the next 7 days, very little precipitation is expected across much of Indiana (Figure 2).  This below-normal precipitation pattern is likely to continue through most of next week.  After that, climate outlooks are favoring near-normal precipitation through September 24th.

Figure 3. Average date of the first fall frost where temperature first reach or drop below 28°F.

Figure 3. Average date of the first fall frost where temperature first reach or drop below 28°F. (Purdue Landscape Report)

Regarding first frost or even hard frost, we are still too early in the calendar year to worry about this being an extensive risk.  Very localized, low-lying areas may be susceptible, but the climatological average date of the first hard freeze (28°F) is often not until mid-to-late October (Figure 3). With temperatures expected to warm again, widespread hard frost is not anticipated prior to October.

Explore the latest Indiana climate and drought maps, including first freeze and frost probabilities, view the Purdue Indiana State Climate Office.

View the original article on the Purdue Landscape Report website: A False Sense of Autumn.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
Alert – Water Your Trees, Watch Video, Purdue Extension – Forestry and Natural Resources Got Nature? Blog
Find an Arborist video, Trees are Good-International Society of Arboriculture (ISA)
ID That Tree, Playlist, Purdue Extension – FNR YouTube Channel
Summer Tree Care, Purdue Landscape Report
Drought? Don’t Forget the Trees!, The Education Store, Purdue Extension resource center
Extreme Heat Including Fact Sheets, Purdue Extension – IN-PREPared
Extreme Heat – Resources, Extension Disaster Education Network (EDEN)
Drought Information​, Indiana Department of Natural Resources
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension YouTube Channel
Tree Defect Identification, The Education Store
Surface Root Syndrome, The Education Store
Submit Sample, Purdue Plant & Pest Diagnostic Lab
What Are Invasive Species and Why Should I Care?, Purdue Extension-FNR Got Nature? Blog
Invasive Species Playlist, Playlist, Purdue Extension – FNR YouTube Channel
Subscribe Purdue Extension-Forestry and Natural Resources YouTube Channel

Beth Hall, Indiana State Climate Office Director
Purdue University Department of Agronomy

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