Here is my exclusive fall outlook for the area.
HOW I BUILT THIS OUTLOOK
Fall in the Mid-Mississippi Valley is a moving target. Summer heat pulls back, the jet stream sharpens, and small nudges in the Pacific can ripple all the way to Perryville, St. Louis, southeast Missouri, southern Illinois, and central Missouri.
To make a sensible forecast for September through November, I lean on three pillars.
First is climatology — what’s “normal.” September steadily cools, October brings the first frosts, and November delivers bigger fronts and the first flirt with winter. Everything else is a departure from this baseline.
Second, I use analog years — past years that looked like our current setup. No two years are identical, but they often rhyme. When several past years share today’s signals, they help shape expectations for temperature swings, storm timing, and frost risk.
Finally, I examine the current large-scale pattern — ocean temperatures, soil moisture, and the late-summer jet stream — to steer me toward the right analogs and weight them correctly.
WHAT ARE “ANALOG YEARS”?
Analog years are past seasons that line up with today’s big-picture setup. For 2025, the closest matches are 1998, 2005, 2010, and 2016.
What they shared:
■ Neutral-to-weak La Niña setup in fall
■ Negative PDO states
■ Late-summer dryness in Missouri and Illinois
■ And what they showed for us:
■ September: Slightly warm overall, cool snaps late
■ October: Quieter early, wetter and stormier late
■ November: Sharp swings, first freezes, soaking systems, and flurries north.
It’s worth remembering: 2010 and 2016 both featured late-season storm systems that disrupted Thanksgiving travel, while 2005 surprised with a warm October that flipped to a stormy November. These echoes matter when we look ahead.
LA NIÑA PRIMER
La Niña is a cooling of the tropical Pacific that tugs on the jet stream. Its fall influence here is subtle, but important:
■ September–October: More northwest flow & warm/cool flips.
■ November: Stronger jet & deeper systems, windy rains, first flurries north.
■ Severe weather: Reduced overall, but late October and November fronts can still pack a punch.
In the Midwest, La Niña tends to quiet early autumn before ramping up November volatility.
OTHER CONTRIBUTING FACTORS
■ PDO (Pacific Decadal Oscillation): S t r o n g l y negative & favors alternating mild/cool spells
■ Soil Moisture: Southern Missouri dry & warmer/ drier early, less important by late October
■ MJO (Madden-Julian Oscillation): Can “flip” us into a wet/cool stretch for a week or two
■ QBO (Quasi-Biennial Oscillation): Bigger player in winter, minor for fall.
These tilt the scales toward a season that begins warmer and drier, then grows stormier and more variable late.
So, let’s check out September, October, and November.
SEPTEMBER 2025
“Lingering Warmth, False Fall Snapshots”
■ Highs: 85°F - 76°F
■ Lows: 66°F - 55°F
■ Rainfall: ~3.1” (normal)
■ Outlook: Near to slightly above normal temps. Rain chances Sept. 14–17 and Sept. 25–28. Frost unlikely.
Forecast Discussion:
September will feel like two different months. The first half carries a summer hangover: warm days, dry fronts, and sluggish Gulf moisture. The back half taps Canadian air, bringing crisp mornings and windows-open afternoons. Dry soils in southern Missouri may exaggerate early warmth, but harvest and outdoor events should run smoothly.
Atmospheric Setup:
Jet stream sits north early; storm track away from Missouri. By the last 10 days, stronger Canadian highs tug the jet south, sharpening fronts. Storms remain weak but hint at the volatility to come.
Nature’s Signs:
Goldenrod blooms, ragweed peaks, dogwoods show early red in cool valleys. Geese begin staging along the Mississippi flyway — a natural signal that summer’s grip is loosening.
OCTOBER 2025
“Crisp Nights, Color on the Hills”
■ Highs: 75°F - 64°F
■ Lows: 55°F - 42°F
■ Rainfall: ~3.4” (normal)
■ Outlook: Slightly cooler than normal. Stronger storm chances Oct. 22–27 and Oct. 29–31.
Forecast Discussion:
October opens quietly with cool mornings and mild afternoons. By mid-month, the jet strengthens, and Gulf moisture reopens, raising the risk of latemonth storms. Expect the first widespread frost in rural valleys between Oct. 15–25; metro St. Louis about a week later. Analogs (1998, 2016) hint at warm starts flipping late — in 2016, 80s early gave way to frosts and strong storms after the 20th. That rhythm could be repeated.
Atmospheric Setup:
Canadian highs dominate early. By the 20th, the storm track strengthens, feeding off both Canadian air and Gulf moisture — a recipe for storm lines and soaking rains.
Nature’s Signs: Peak color arrives mid-to-late month. Deer rut begins on frosty mornings. Crickets fade, replaced by the crunch of leaves.
November 2025 – “First Freeze, Blustery Storms”
■ Highs: 59°F - 48°F
■ Lows: 41°F - 32°F
■ Rainfall: ~3.6” (normal)
■ Outlook: Highly variable. Two to three soaking systems are likely. Flurries possible north late month.
Forecast Discussion:
November is the pivot to winter. Expect swings: a 65° Sunday followed by a 38° Monday. At least one windy, soaking storm is likely in the first half, with Thanksgiving week as a prime candidate for another disruptive system. Analogs favor clippers or southern stream lows tracking through the Ohio Valley — cold rain for many, wet flakes for northern Missouri.
Atmospheric Setup:
Polar jet deepens south; storms track every 3–5 days. Stronger Canadian highs bring hard freezes, typically Nov. 5–15 across the region. Nature’s Signs: Oaks drop late leaves. Gardens go dormant. Snow geese and ducks peak in migration, filling skies with sound and movement as winter approaches.
SUMMARY
Fall 2025 is shaping up to be a classic Midwestern fall: stretches of mild beauty, crisp frosts, blustery rains, and maybe flurries north of I-70 before December.
For farmers, September favors harvest progress; October’s late rains may briefly slow things. For families, October festivals and football bring crisp days, but keep a backup plan late in the month. For travelers, Thanksgiving week stands out as a storm window.
This fall continues the theme of weak La Niña years — variability is the rule. Warmth sneaks in, but sharp cold snaps and stormy systems balance it out. Communities should use early quiet weeks to prepare for late volatility.
And remember: fall often sets the stage for winter. If the analogs hold, November’s storminess may be a preview of an active start to winter.
So enjoy the season — the crisp mornings, the colors, the geese overhead — and be ready for the surprises that always come with Midwest fall.
