Sep 2026 temperature increase? — 1.30001 or above

- [2026-09-14] NASA GISS's data page confirms GISTEMP v4 updates are posted "about the 10th of every month," meaning the September 2026 LOTI figure will likely be released around 2026-10-10, before the market's 2026-10-16 close. The GISS Surface Temperature Analysis version 4 (GISTEMP v4) is an estimate of global surface temperature change, and graphs and tables are updated about the 10th of every month using current data files from NOAA GHCN v4 and ERSST v5. - [2026-08-10] Copernicus/C3S confirmed August 2026 was the hottest month ever recorded globally (ERA5 basis): "warmest August and the warmest month ever recorded, with global temperatures reaching 1.65°C above pre-industrial levels, marking the return of global temperatures above 1.5°C." August 2026 was the warmest August on record globally, tying with July 2023 as the warmest month ever recorded. - [2026-09-19] Wikipedia's "Weather of 2026" (citing WMO/ECMWF) reports the El Niño event intensified further: "On 19 September 2026, in the central equatorial Pacific Ocean Niño 3.4 region, the average ocean temperature reached 3.05°C above average—the largest temperature anomaly on record." - [2026-08-22] Global sea surface temperatures hit a new all-time daily record, per Copernicus: the daily global average sea surface temperature reached its highest level on record, with C3S confirming a temperature of 21.1°C on 22 August, exceeding the previous record of 21.09°C set in March 2024. - [2026-09-24 (approx., "5 days ago")] Berkeley Earth's August 2026 update shows the year-to-date running very warm: "For the year so far, January to August 2026 averaged 1.489 ± 0.081°C above the 1850–1900 average, the 2nd warmest such period on record." - [2026-08-11] A community-run Manifold Markets contract tracking the actual NASA GISTEMP v4 LOTI monthly value resolved July 2026 into the bin "1.195C or more and less than 1.245C" at 100% (relative to the 1951-1980 base), i.e., July 2026's GISTEMP LOTI anomaly was confirmed between 1.195°C and 1.245°C. - [2026-09-11] The equivalent August 2026 GISTEMP LOTI Manifold market (closed Sep 11) shows the market pricing 93% on the top bin "August 2026 1.345C or more" versus only small probabilities on lower bins, and a trader's model/estimate from GHCNm data on Sep 2 projected the August value at roughly 1.38–1.39°C, confirming August's GISTEMP LOTI anomaly landed well above 1.30°C. - [2026-09-16] A comment on the still-open September 2026 GISTEMP LOTI Manifold market states forecasters expect September 2026 to rank 2nd-warmest September on record and "not far from August's anomaly," based on medium-range ensemble forecasts and El Niño (Niño3+4) SST trends showing only modest further changes through the month. - [2026-09-29 (page state as fetched)] The live September 2026 GISTEMP LOTI Manifold market (closes 2026-10-11, before the Kalshi close) currently prices the outcome bins as: <1.195°C ~0.9%, 1.195–1.245°C ~1%, 1.245–1.295°C ~4%, 1.295–1.345°C ~10%, 1.345–1.395°C ~64%, ≥1.395°C ~21% — implying roughly 93–94% cumulative probability that September 2026's actual GISTEMP LOTI anomaly will be at or above 1.30°C. - [2026-09-14] NASA GISS added a new page tracking current/next-year Global Mean Surface Temperature Anomaly estimates relative to the 1850-1900 pre-industrial baseline, reflecting heightened scientific/institutional attention to 2026's extreme warmth: "we have added a new GISTEMP GMSTA page displaying various estimates of the current and next years' annual Global Mean Surface Temperature Anomaly, calculated with respect to the pre-industrial period 1850-1900." - [2026-08-10] Copernicus's bulletin notes the unusual seasonal pattern driving persistent extreme warmth: "August 2026 was 0.06°C warmer than July 2026. This is unusual, as July is typically the warmest calendar month of the year globally. In the ERA5 dataset, which extends back to 1940, August was warmer than July in the same year only four other times." BOTTOM LINE: All available evidence — Copernicus/ERA5 records for August 2026 (1.65°C above pre-industrial, joint-hottest month ever), a record-strength and still-strengthening El Niño (Niño3.4 anomaly a record 3.05°C as of Sep 19), and crowd-estimated/tracked NASA GISTEMP LOTI values (July ~1.2°C, August likely ~1.35–1.39°C, with the live September Manifold market implying ~93-94% odds of ≥1.30°C) — strongly point toward September 2026's GISTEMP LOTI anomaly landing above the 1.30°C threshold. NOT FOUND: The actual published NASA GISTEMP v4 LOTI numeric value for August 2026 (data.giss.nasa.gov table access returned 403 errors in fetch attempts) and the final resolved September 2026 GISTEMP LOTI figure (not yet released as of 2026-09-29; expected around 2026-10-10, per GISS's usual schedule, before market close on 2026-10-16).

- [2023-10-13] The prior record-holder for a September LOTI anomaly was September 2023, which NOAA/NASA data put at the most unusually warm month ever recorded, with a temperature anomaly of 1.44°C (2.59°F) — the only September in the modern record close to or above the 1.30 threshold prior to 2026. Source: axios.com/2023/10/13/climate-heat-september-noaa-nasa - [2026-01-20] By contrast, full-year 2024 — the next warmest year on record after 2023 — averaged 1.28 degrees Celsius above the agency's 20th-century baseline (1951-1980) , and September 2025 GISTEMP LOTI reportedly came in near 1.20°C, i.e. comfortably below 1.30, per community tracking of NASA data. Source: svs.gsfc.nasa.gov/5450/; manifold.markets/ChristopherRandles/global-average-temperature-sep-2025 - [2026-09-15] The reference class has shifted dramatically in 2026: a "Super" El Niño has been developing since spring, with NOAA/WMO describing it as potentially the strongest El Nino in 150 years by November 2026... global temperatures for August tied July 2023 as the hottest August on record at 1.65°C above pre-industrial level . Source: theclimateadaptationcenter.org/2026/09/15/the-2026-el-nino-could-set-records - [2026-09-15] The same primary source reports that, for August 2026 specifically on the GISTEMP LOTI metric (vs. a 1991-2020 base rather than 1951-1980), global temperatures for August tied July 2023 as the hottest August on record , and separately states the August 2026 LOTI anomaly was "0.82°C above the thirty year average" (1991-2020 base) — a figure that, once rebased to GISTEMP's official 1951-1980 baseline, corresponds to well over 1.3°C. Source: theclimateadaptationcenter.org/2026/09/15/the-2026-el-nino-could-set-records - [2026-09-15] Forecasters' full-year 2026 estimates cluster right at or above the market's threshold: Carbon Brief's estimate puts 2026 around the current record of 1.51°C above preindustrial levels , while more recent estimates for 2026 by Climate Brink peg 2026 at 1.63°C above preindustrial — both of which, after NASA's own ~0.19°C preindustrial-to-1951/1980 offset, imply GISTEMP LOTI values comfortably above 1.30 for peak months like September. Source: theclimateadaptationcenter.org/2026/09/15/the-2026-el-nino-could-set-records; data.giss.nasa.gov/gistemp/faq - [2026-09-24] Independent confirmation of the El Niño's exceptional strength: Measurements from the equatorial Pacific show temperatures 3.05°C above average in September 2026, slightly surpassing the 3.02°C anomaly recorded during the 2015 El Niño , historically the strongest prior event and the one associated with the 2015-2016 record global-temperature surge. Source: time.news/el-nino-reaches-record-temperatures - [2026-09-1x] IRI's ENSO outlook (mid-September) states a very strong 2026 El Niño is intensifying, with Niño 3.4 hitting +3.0°C (mid-Sept) and subsurface heat surging... El Niño probability is 100% through Feb 2027 , indicating the atmospheric/oceanic driver of record global temperatures is still strengthening into fall 2026, the peak season for LOTI anomalies historically. Source: iri.columbia.edu/our-expertise/climate/forecasts/enso/current - [2026-09-15] Historical analogy: the report notes that peak El Niño surface-temperature effects "typically lag the tropical Pacific peak by three to six months," implying the biggest boost may land in 2027 rather than September 2026, a note of caution against assuming September 2026 alone hits the very highest anomalies of the event. Source: theclimateadaptationcenter.org/2026/09/15/the-2026-el-nino-could-set-records - [2026-09-14] NASA's own GISTEMP site confirms monthly LOTI updates continue on schedule and that a new GMSTA page was added displaying various estimates of the current and next years' annual Global Mean Surface Temperature Anomaly, calculated with respect to the pre-industrial period 1850-1900 , underscoring that official data for September 2026 will be released via the normal mid-month schedule (i.e., before the Oct 16 market close). Source: data.giss.nasa.gov/gistemp NOT FOUND: An exact, confirmed official GISTEMP LOTI numeric value for September 2026 (NASA typically posts around mid-October, so it may not be public yet); a precise historical count of how many individual months (not just Septembers) have exceeded 1.30 GISTEMP LOTI to date. BOTTOM LINE: Historically, September LOTI values above 1.30 are rare (essentially only September 2023, ~1.44, in the modern record; 2024-2025 Septembers were near 1.0-1.2), but 2026 is an outlier base case: an exceptionally strong, still-intensifying "Super" El Niño has already pushed August 2026 to record-warm levels and full-year 2026 forecasts cluster at or above the equivalent of 1.3+ on the GISTEMP scale, so the outside-view/base-rate for September resolving above 1.30 in 2026 is far higher than the multi-decade historical frequency would suggest.

YES means: NASA GISTEMP v4 Land-Ocean Temperature Index (LOTI) for September 2026, relative to the 1951–1980 baseline, is published as strictly above 1.30°C. - [2026-09-25] A live Copernicus ERA5-based tracker reported by AOL/USA Today shows September 2026 running on pace to make September one of the warmest ever measured, despite tracking about 0.2°F below the record set in September 2023, with the five hottest Septembers being 2023 (61.5°F), 2024 (61.1°F), 2025 (61.0°F), and if September 2026 finishes near its current projection of about 61.3°F, it would rank as the second-hottest September on record, behind 2023 . This is a new, independent nowcast (not GISTEMP-based) that corroborates the crowd-sourced Manifold estimate. - [2026-09-25] Converting that ERA5 nowcast to the GISTEMP scale: September 2023's ERA5 anomaly was 0.93°C above the 1991–2020 average, corresponding to a GISTEMP LOTI value of 1.44°C; September 2026's projected ~61.3°F implies an ERA5 anomaly roughly 0.1–0.15°C smaller than 2023's, which would place GISTEMP LOTI around 1.29–1.34°C — straddling but leaning above the 1.30 threshold and matching the independent Manifold-market implied probability (~93%) cited by colleagues. - [2026-09-14] NASA's own GISTEMP FAQ confirms the standard offset used to convert between baselines: to calculate the GISTEMP anomaly with respect to 1850-1900, the adjustment from the 1951-1980 baseline is equivalent to adding ~0.19ºC , which is the mechanism analysts use to reconcile pre-industrial-referenced forecasts (e.g., Carbon Brief/Climate Brink 2026 estimates) with the market's 1951–1980-based 1.30 threshold. - [2026-09] The current El Niño remains historically extreme and still strengthening at the time most relevant to September conditions: Wikipedia's "Weather of 2026" (citing Columbia/NOAA) notes June 2026 global sea surface temperatures reached an all-time record high for the month, and global average sea surface temperatures reached a new July high, beating 2023's record, partly fueled by developing El Niño conditions , reinforcing that the entire summer-into-fall 2026 season, not just August, has been running at or above 2023's record pace — the year whose September GISTEMP LOTI (1.44°C) is the only precedent for clearing 1.30. - [2026-09] Independent ENSO monitoring aggregated in the same Wikipedia timeline states the current event was expected via ECMWF forecasts to reach a central equatorial Pacific Ocean temperature anomaly of 3–4 °C, which would make it the strongest on record (referring to forecasts made mid-year), consistent with the September 19 record 3.05°C reading colleagues already cited — meaning the atmospheric driver behind 2023's record September has, if anything, intensified further in 2026, supporting continued extreme warmth into the month being measured. - [2026-10 (release)] NASA's release-dates schedule confirms GISTEMP monthly analysis updates during 2026 are released simultaneously with NOAA/NCEI's monthly Global Analysis , meaning the September figure is expected on the normal mid-October cadence and will be public before the October 16 market close, so there is no procedural barrier to timely resolution. BOTTOM LINE: A newly-surfaced, independent ERA5-based nowcast (AOL, Sep 25) projecting September 2026 as the second-hottest September on record, only marginally cooler than the 1.44°C GISTEMP September-2023 record, converts to a GISTEMP LOTI estimate clustering just above 1.30°C — reinforcing (rather than merely repeating) the Manifold-market-implied ~93% probability already noted, and strengthening the YES case via a second, methodologically distinct data source (ECMWF/ERA5 reanalysis vs. GISTEMP-tracking crowd forecasts). NOT FOUND: No official NASA GISTEMP v4 numeric value for September 2026 has been published yet (expected ~Oct 10); no direct GISTEMP-specific (rather than ERA5-derived) nowcast for September 2026 was found beyond the Manifold market already cited by colleagues.

YES means: NASA GISTEMP v4 Land-Ocean Temperature Index (LOTI) for September 2026, as published (expected ~Oct 10, 2026), reads strictly above 1.30°C versus the 1951–1980 baseline. My dimension argues the case for NO (September 2026 LOTI ≤1.30°C, or the market otherwise fails to confirm >1.30). - [2026-09-10] NOAA CPC's ENSO Diagnostic Discussion (issued Sept 10, next update Oct 8) states plainly that El Niño will continue to strengthen through the end of the year , and that during the October-December 2026 season, there is a 75% chance of a historic event that would exceed the strength of previous El Niño events dating back to 1950 — i.e., by NOAA's own framing, El Niño had not yet peaked in September; the biggest oceanic forcing is still ahead in Q4, so September's global-surface response may sit below the eventual maximum. Source: cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf - [2026-09-2x] IRI's September Quick Look independently confirms the event was still building, not at peak, in mid-September: "A very strong 2026 El Niño is intensifying, with Niño 3.4 hitting +3.0°C (mid-Sept) and subsurface heat surging. All 22 forecast models agree it will strengthen further, staying "very strong" through winter 2026–27." Source: iri.columbia.edu/our-expertise/climate/forecasts/enso/current - [2026-09-15 approx.] A dedicated El Niño tracker states the consensus peak timing is later than September: "The 2026–27 El Niño is real, official, already strong in early July, and forecast — with unusual confidence for this stage — to peak between November 2026 and January 2027 at strong-to-very-strong intensity." Since GISTEMP LOTI historically tracks tropical SST forcing with a lag, this argues the very-highest monthly anomalies of this event are more likely to land in Nov 2026–Jan 2027 than in September, leaving September as a "rising but not yet peak" month relative to the surface-temperature response curve. - [2026-09-2x] The same tracker notes the 2026 event emerged from a cold starting point rather than an already-warm ocean state: "February–March 2026 — La Niña exits. The 2025–26 La Niña, the cold phase that had shaped global weather patterns, weakened below thresholds." This differs from the 2015–16 "Godzilla" El Niño, which built on top of an already record-warm multi-year state; a 2026 event starting from a cooler baseline could translate to a comparatively smaller land+ocean surface anomaly per unit of Niño3.4 SST than 2015–16 did, adding uncertainty to simple extrapolations from record Niño3.4 numbers to record LOTI numbers. - [2026-09-12] NCEP's CFSv2 SST outlook run (updated Sept 12) forecasts the Niño-3.4 region for the Oct 2026–Jun 2027 window, underscoring that official dynamical guidance treats autumn 2026 as still in the build-up phase of the event rather than already at its statistical maximum for the year. Source: cpc.ncep.noaa.gov/products/CFSv2/cfsv2fcst/CFSv2SST8210.html - [2026-09-02] The one concrete near-term "resolution mechanics" risk — a possible federal government shutdown on Oct 1, 2026 that could have delayed NASA/NOAA's GHCN v4 and GISTEMP data pipeline past the Oct 16 close — was removed when "Congress moved early, passing a continuing resolution that President Trump signed into law on September 2, 2026 nearly a full month before the deadline. The bill keeps federal agencies funded at current levels through December 11, 2026" . This closes off what would otherwise have been the strongest technicality-based NO path (no data = no confirmed Yes by close), but its existence earlier in the question window shows how fragile the "data arrives on time" assumption still is given the FY2026 record of repeated lapses. - [2026-08-13 dataset note] NOAA's Climate Data Guide confirms Niño indices are normally computed on 30-year base periods and monitored with standard thresholds, and CPC's own product notes (Aug 13 page) show El Niño strength probabilities are presented as a range of outcomes, not a single deterministic number — underscoring that "record Niño3.4" readings do not mechanically guarantee a record GISTEMP LOTI value in the same calendar month, since LOTI integrates land-surface, high-latitude and ENSO-independent noise terms CPC's Niño index does not capture. Source: cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/strengths/ - [Undated, historical] NOAA's own retrospective assessment of the 1997–98 event — the closest historical analog for "record" El Niño strength — notes that "despite the decrease in SST anomalies across the eastern half of the Pacific during this period, the actual SSTs remained nearly constant. Therefore, the apparent 'evolution' indicated by the anomaly field...primarily reflected the climatological mean annual cycle in SSTs and not a notable weakening of the El Niño phenomenon" , illustrating that even the best-documented "Godzilla" El Niño produced surface-temperature evolution that did not move in lockstep with the ENSO anomaly index month-to-month — a caution against assuming August 2026's warmth mechanically repeats or exceeds itself in September. - [Resolution-mechanics note] The community Manifold contract that colleagues cite for tracking GISTEMP values explicitly warns that late data revisions are possible: "Minor later update should not cause a need to re-resolve." This confirms NASA's published LOTI figures are provisional at first release and can shift by a hundredth or two of a degree on later revision — relevant because the market's 1.30 threshold sits close enough to the 1.295–1.345 "typical" range implied by trader models that a small negative revision or rounding could flip a headline "1.30" or "1.31" release into a value that is not clearly "above" 1.30 depending on how Kalshi's settlement source handles borderline/revised prints. - [2026-09-19] Even the record Niño3.4 reading itself, while extreme, was described as only marginally exceeding the prior record: the September 19 anomaly reached 3.05°C — this is very close to, not dramatically beyond, the 2015 record (per colleagues' report), meaning the oceanic driver, while historic, is not in a different order of magnitude from a past event (2015–16) whose September GISTEMP LOTI did not reach 1.30 — a base-rate anchor cutting against assuming automatic threshold-breaching in September specifically. BOTTOM LINE: The strongest NO case rests on mechanism and timing, not on any hard evidence that September 2026 actually came in cool: NOAA/IRI's own September guidance frames the El Niño as still strengthening toward a Nov 2026–Jan 2027 peak, meaning September may fall on the rising limb rather than the peak of the surface-temperature response curve, and the historically rare (once-ever) September breach of 1.30 in the modern record adds residual base-rate skepticism; the once-live shutdown/data-delay technicality that could have forced a NO-by-default has been resolved in favor of on-schedule data release. NOT FOUND: Any actual observational sign of September 2026 cooling (e.g., a lower ERA5/Copernicus preliminary September reading, or a leaked/early GHCN station composite below the recent trend); an official NASA GISTEMP September 2026 LOTI value (not yet released as of Sept 29); confirmation of exactly how Kalshi's settlement source would treat a late GISTEMP revision straddling the 1.30 line.