Correction and editorial revision — 23 October 2026: This retrospective replaces the earlier mixed-time narrative with dated provider observations. The earlier heatwave-to-inflation projection lacked an identified impact calculation and retained event sources. The earlier causal explanations and trading implications are withdrawn; their removal is not a finding that every cited event was false. The original input file is unavailable. The cutoff below is the calendar day before the original publication date, selected for this reconstruction; it is not a claim about what was known when the original article was written.
This archive review uses observations available in the retrieved daily history on or before 2026-04-28. Each market has its own closing time. The question is: Can Market Quotes Measure a Heatwave Inflation Effect?
The measured comparison
WTI futures moved from $96.37 on 2026-04-27 to $99.93 on 2026-04-28: +3.69%, or $+3.56 per barrel in the quoted series. The five-interval change from 2026-04-21 was +8.47%. WTI futures history.
The US 10-year yield proxy changed +1.8 basis points over 2026-04-27–2026-04-28, while gold futures changed -1.82% over 2026-04-27–2026-04-28. These observations do not quantify lost production, shipping capacity or an inflation pass-through. An oil-price change cannot on its own separate a supply effect, a demand effect and futures-contract effects.
Reproducing the longer comparison
For WTI futures, the five-interval baseline is 92.13 on 2026-04-21; the endpoint is 99.93 on 2026-04-28. The calculation is (endpoint ÷ baseline − 1) × 100 = +8.47%. This uses the endpoints directly rather than adding rounded daily percentages. Five observations need not correspond to one calendar week when a market is closed.
Source-linked daily observations
| Series | Previous date | Previous value | Date | Value | Change | Time zone |
|---|---|---|---|---|---|---|
| KOSPI (^KS11) | 2026-04-27 | 6,615.03 | 2026-04-28 | 6,641.02 | +0.39% | Asia/Seoul |
| S&P 500 (^GSPC) | 2026-04-27 | 7,173.91 | 2026-04-28 | 7,138.80 | -0.49% | America/New_York |
| Nasdaq Composite (^IXIC) | 2026-04-27 | 24,887.10 | 2026-04-28 | 24,663.80 | -0.90% | America/New_York |
| US 10-year yield proxy (^TNX) | 2026-04-27 | 4.336 | 2026-04-28 | 4.354 | +1.8 bp | America/Chicago |
| WTI futures (CL=F) | 2026-04-27 | 96.37 | 2026-04-28 | 99.93 | +3.69% | America/New_York |
| Gold futures (GC=F) | 2026-04-27 | 4,693.70 | 2026-04-28 | 4,608.40 | -1.82% | America/New_York |
| USD/KRW (USDKRW=X) | 2026-04-27 | 1,474.69 | 2026-04-28 | 1,473.00 | -0.11% | Europe/London |
| USD/JPY (USDJPY=X) | 2026-04-27 | 159.58 | 2026-04-28 | 159.36 | -0.14% | Europe/London |
| VIX (^VIX) | 2026-04-27 | 18.02 | 2026-04-28 | 17.83 | -1.05% | America/Chicago |
Scope and limitations
Returns are calculated before rounding from Yahoo Finance daily history, not independently verified exchange settlement records. Index values are in points; the yield proxy is quoted in percent; currency quotes are local units per US dollar; gold and WTI futures are dollars per ounce and barrel. Futures-series changes can reflect contract rolls and are not a continuously held contract’s investment return. These are retrospective observations, not live prices or a reconstruction of every intraday quote available to the original author.
For the underlying method, see the Hormuz evidence and import-cost guide. This page retains its original address for correction transparency. The title and text now reflect the narrower evidence available; the old URL wording should not be treated as a current claim. No trading instruction is retained.