Illinois's warmest September and October since 2015 met the highest ammonia barge month since 2018; November lock counts test whether tonnage moves to spring

Why these series belong together

Illinois growers apply part of their corn nitrogen in the fall as anhydrous ammonia, once 4-inch soils settle below 50 °F, from terminals filled by barge. Three public series follow that chain: statewide temperature (NOAA NCEI), upbound ammonia through Mississippi River Locks 27 near St. Louis (Corps of Engineers via USDA AgTransport) and the Illinois distributor ask (USDA AMS), with rainfall and topsoil moisture beside them. No series here measures soil temperature or acres applied.

What the weather did

September 2026 averaged 73.0 °F [F19], against a previous 2015–2026 high of 71.6 [F20]; October 61.9 °F [F66], against 60.2 in 2021 [F60]. The Illinois State Climatologist ranks October third warmest on the record since 1895. October rain, 1.80 inches [F65], was inside the 2021–2025 range of 0.90 [F39] to 6.02 [F43], after a wet August [F21]; the Palmer index stayed positive [F67]. Topsoil short or very short rose from 35 percent in the week ending 4 October [F25] to 49 on 1 November [F24], against 65 in 2024 [F27]. The U.S. Drought Monitor (National Drought Mitigation Center, USDA, NOAA, NASA) put 37.7 percent of the state in moderate drought or worse on its map of 3 November, released 5 November; it is cited at its source and not carried as a series here.

What the barges and the price did

Locks 27 passed 92,020 short tons of ammonia upbound in September [F1], the highest month since the series began in January 2018, in 34 barges of about 2,706 tons; October brought 47,600 [F2], fifth of nine Octobers. The two months total 139,620, level with the 2018 high of 139,700 [F3] [F4]. The Illinois River lock counted 27,000 and 28,400 [F7] [F8]; the river joins the Mississippi above Locks 27, so by geography its upbound count is a component of the Locks 27 count, up to lags across month boundaries.

The Illinois distributor ask was 981.11 dollars per short ton on 30 October [F31], in a range of 850 to 1,060 and up 33.61 in two weeks with urea [F37] and UAN [F38] unchanged. The series is empty from February 2022 to that report; October 2021 ran 856.50 [F33] to 1,135 [F32]. CVR Partners' third-quarter gate price was 637, LSB Industries' Tampa benchmark 622; DTN's national retail average was 987 in mid-October.

The spring-shift claim against the data so far

The trade-press claim is that dryness and warmth narrow the window and push tonnage to spring 2027. It is not supported so far: its first consequence, fall receipts below prior years, did not occur [F1] [F2] [F3]. The Illinois Fertilizer & Chemical Association said on 23 October that soils were still too warm; American Farmland Trust reported applications picking up across Illinois on 5 November. On the University of Illinois average, soils settle below 50 °F after the first week of November: the fall is not shown to be late. Two dated tests remain: November barges (about 5 December) and March–April 2027 (about 5 May).

The mechanism, and what else could explain it

Hypothesis · With the tonnage delivered, the binding step this fall is at the field: soil temperature, and on dry ground whether knives reach six inches and the slot seals, a test no series records. A deferral would show first as November below 36,600 at Locks 27 [F5] with the Illinois River below 6,000 [F9].

Hypothesis · Two other readings compete. If the record September filled terminals early, a low November at Locks 27 with the Illinois River inside its range would measure full storage, not a curtailed window. And the ask follows inland supply and the global benchmark: CVR's East Dubuque plant ran at 80 % until mid-October, and CF Industries names a tight global balance. The data cannot attribute the rise to weather.

Who sits on this chain

CVR Partners, CF Industries and Koch Fertilizer supply the ammonia; LSB Industries anticipates robust demand through fall 2026 and spring 2027. GROWMARK runs 230 pressurized trailers across Illinois and Iowa. Kirby operates 10 refrigerated ammonia barges. Corteva sells the nitrapyrin inhibitor used with it.

Hypothesis · Deduced: Nutrien, CHS and Ehler Bros. store and apply on the same calendar; CoBank finances such inventory. Union Pacific rail and Sunoco pipelines are the other winter modes; with no modal-share source, they are adjacent to a shift, not measured in it.

A conditional sensitivity, not a forecast

Scenario · Assume tonnage is deferred. November's past range at Locks 27, 36,600 [F5] to 68,400 [F6], is 13.5 to 25.3 barge-loads at September's load. Terminals above Lynxville lose the barge from early December to mid-March (97 days last season), so deferred tonnage meets the March fertilizer peak, 141,600 [F64] to 1,037,950 tons [F63] of all kinds. The deferral case needs March plus April 2027 above 82,900, the 2022 high [F11] [F13], with 92,020 [F1] as the demonstrated monthly ceiling.

What would change this reading

Hypothesis · November at Locks 27 at or above 36,600 [F5] reads as an ordinary season, with March and April 2027 inside 12,400 [F12] to 52,900 [F11] and 3,000 [F14] to 30,000 [F13]. Below 36,600 with the Illinois River at or above 6,000 [F9] reads as full terminals, spring inside the same ranges; below both thresholds, as deferral, spring above both highs. CPC models favor a warmer northern tier in November and the State Climatologist leans toward a warmer Illinois November; the AMS reports of 13 and 27 November show whether the ask follows Tampa.