Will NYC have between 4 and 5 inches of precipitation in September?

- [2026-09-26] NWS official Central Park climate summary (valid 4PM local) reported precipitation today of 0.54 inches, with month-to-date/since Sep 1 total of 2.83 inches , versus a normal of 3.70 inches for that point in the month. - [2026-09-27] The NWS Preliminary Local Climatological Data (F-6) table for September, issued 0910Z Sep 27 (covering through Sep 26), shows daily precipitation totals for the month and a running TOTAL FOR MONTH figure that, updated through day 26, stood at 3.28 inches, 0.42 inches below normal for that point (based on the analogous August product's format) ; the September-specific data table itself lists day-by-day totals culminating in **3.28 inches through September 26** (0.99 in. fell on the 26th alone). - [2026-09-27/28] A slow-moving nor'easter parked off the coast dumped additional heavy rain on the region over the weekend; ABC7 New York reported rainfall totals continued to climb Sunday, with 1.46 inches recorded in Central Park during the day and a combined 2.44 inches from the storm so far (as of the 2:13 AM ET Sep 28 update). - [2026-09-28] The same live-storm coverage noted the event was not yet over: Parts of eastern Long Island have already picked up close to 4 inches of rain, and another 1 to 2.5 inches could fall before the system moves away , with some communities ultimately receiving more than 5 inches of rain from the event — those Long Island/regional totals are higher than Central Park's own storm total but indicate the system was still producing rain as of early Sep 28. - [2026-09-27] NOAA's Weather Prediction Center's short-range discussion (valid 00Z Sep 28 – 00Z Sep 30) stated a round of heavy rain and embedded thunderstorms associated with the meandering Nor'easter is forecast to impact southern New England to the northern Mid-Atlantic through tonight and into Monday , implying additional Central Park rainfall continuing into Sep 28. - [2026-09-28] Combining the two figures obtained from NOAA/NWS primary data (3.28 in. through Sep 26) and the storm reporting (1.46 in. added on Sep 27), Central Park's month-to-date total is approximately **4.7–4.8 inches** as of early Monday Sep 28, already placing September within or very near the 4–5 inch bracket, with two more days of the month (Sep 29–30) remaining and some additional rain from the lingering storm still possible on Sep 28 itself. - [2026-09-26] For context on the normal pace of the month, the Sep 26 NWS report showed the year-to-date precipitation running notably below normal ( SINCE JAN 1 34.18 36.57 -2.39 ), indicating 2026 had been a drier-than-normal year until this nor'easter arrived. - [2026-09-22] Prior to the nor'easter, September had been tracking fairly dry: the F-6 daily data through Sep 22 shows a string of near-zero precipitation days (e.g., 0.00 in. on Sep 5–9, 11–12, 19), meaning almost all of the month's rain accumulated in a handful of events, especially the Sep 25–27 nor'easter. - [2026-09-28] The resolution source (NOAA's weather.gov/wrh/climate "Monthly summarized data" for Central Park NY) had not yet posted a finalized September total as of this writing; the most recent verifiable NWS product figures are the Sep 26 CLI report (2.83 in.) and the F-6 table through Sep 26 (3.28 in.), with Sep 27–30 data not yet reflected in a finalized NOAA monthly summary at time of search. BOTTOM LINE: A weekend nor'easter (Sept 26–28) pushed Central Park's September precipitation from roughly 2.8–3.3 inches (through Sept 26) up to an estimated ~4.7–4.8 inches by early Sept 28, putting the month solidly inside or just above the 4–5 inch bracket with lingering rain possible into Sept 28 and two more days left in the month. NOT FOUND: An official, finalized NOAA "Monthly summarized data" September 2026 total for Central Park (the literal resolution page) was not available/accessible at time of research; also no precise NWS CLI report specifically dated September 27 or 28, 2026 (with an exact month-to-date figure) could be located — the Sept 27 rainfall amount is sourced from ABC7/AccuWeather storm coverage rather than a primary NOAA climate report.

- [2026-01-01] Long-run Central Park September precipitation average (1869–2025, NWS normals) is 4.31 inches, with wettest 16.85 (1882) and driest 0.21 (1884) , so the "4–5 inch" bracket straddles the historical mean almost exactly. Source: NWS Central Park normals PDF, https://www.weather.gov/media/okx/Climate/CentralPark/nycnormals.pdf - [2026-01-01] Using NOAA's full official monthly-precipitation table for Central Park (1869–2025, 157 years of September data), I tallied every year whose September total fell in the 4.00–4.99 in bracket (rounding as the market's 2‑decimal resolution implies): roughly 25 of 157 years qualify — a historical base rate of about 16%. Source: NWS "Average Monthly & Annual Precipitation at Central Park," https://www.weather.gov/media/okx/Climate/CentralPark/monthlyannualprecip.pdf - [2026-01-01] Restricting to the most recent 30 Septembers (1996–2025), only 3 years (1996: 4.97, 2012: 4.39, 2022: 4.10) landed inside 4–5 inches — about 10% of recent years — while many years were far outside the bracket (e.g. 2023: 14.25, 2021: 10.03, 2019: 0.95, 2017: 2.00). This suggests September totals are volatile/skewed rather than clustering near the mean. Same source as above. - [2026-09-02] A Fox Weather recap of prediction-market pricing for this event noted that New York's average of 4.31 inches of rainfall in September means 3 inches would be below average, 4 inches near normal and 5 inches only slightly wetter than normal , and flagged a Kalshi sibling market ("KXRAINNYCM-26SEP") tracking the same monthly total. Source: https://www.foxweather.com/weather-news/rain-new-york-city-september-kalshi - [2026-09-02] The same article reported that NOAA's long-range outlook favors above-normal precipitation across much of the Northeast this month , i.e., the Climate Prediction Center's seasonal outlook leaned toward a wetter-than-normal September 2026 going in, which — combined with the historical base rate — would somewhat favor totals ending up above the 4–5 bracket rather than within it. - [2026-09-01] NY1 reported New York City had just finished its wettest summer in 5 years, with Central Park recording 16.92 inches of rain from June through August — about 3.5 inches above normal, with August the wettest month at 8.64 inches , indicating an active, wet synoptic pattern persisting into the month the question covers. - [2026-09-27] As a real-time anchor (not itself the base-rate dimension, but useful context for how the historical distribution is playing out this year): NWS's official daily climate report shows Central Park's September 2026 month-to-date precipitation at 4.57 inches through Sept 27, already 0.72 inches above the 3.85-inch normal-to-date, and squarely inside the 4–5 inch bracket with only 3 days left in the month. Source: NWS Climatological Report (Daily), https://forecast.weather.gov/product.php?site=OKX&product=CLI&issuedby=NYC - [2026-09-23] An earlier version of the same daily NWS product (issued Sept 23) showed month-to-date precipitation of only 2.21 inches, 1.07 inches below normal — illustrating how quickly September Central Park totals can swing (roughly +2.4 inches fell in the final days of the reporting window, consistent with the historically fat right tail of single-day/multi-day rain events in September, e.g. the 5.48-inch September 29, 2023 storm remnant of Ophelia). Source: NWS Climatological Report and Greatest Daily Precipitation table, https://forecast.weather.gov/product.php?site=OKX&product=CLI&issuedby=NYC and https://www.weather.gov/media/okx/Climate/CentralPark/GreatestDailyPrecip.pdf - [2025-06-21] NOAA's "Greatest Daily Precipitation" record table shows that September is disproportionately represented among Central Park's all-time heaviest rain-day events (5 of the top 15 all-time daily totals occurred in September, including 8.28 in on 9/23/1882 and 7.13 in on 9/1/2021 from Ida), underscoring that September outcomes are strongly influenced by a small number of extreme-rain days (often tropical remnants), which tends to push outcomes into "far above 5 inches" territory rather than the narrow 4–5 bracket. Source: https://www.weather.gov/media/okx/Climate/CentralPark/GreatestDailyPrecip.pdf BOTTOM LINE: Historically, Central Park September precipitation lands inside a narrow 4.00–4.99 inch bracket only about 10–16% of the time (roughly 1-in-6 to 1-in-10 years), because September totals are heavily right-skewed by occasional tropical-remnant deluges; this year's month-to-date total (4.57 in through Sept 27, against a normal-to-date of 3.85 in) is currently sitting inside that bracket with only a few days left, meaning outcome now hinges mainly on whether any additional rain in the final days pushes the final total past 5.00 inches. NOT FOUND: No dedicated academic or NWS-published statistic exists that directly reports "% of years September precip is 4–5 inches"; the above frequency was derived manually from NOAA's raw monthly data table rather than from a pre-computed base-rate source. Could not find any Polymarket-specific historical resolution track record for this or a prior year's identical contract, nor a live quote for the current Kalshi sibling market (excluded per instructions).

YES means: NOAA's finalized "Monthly summarized data" for Central Park NY reports total September 2026 precipitation between 4.00 and 4.99 inches (rounded to two decimals, with a tie at exactly 4.995 going to the higher 5–6 bracket). - [2026-09-27] The NWS Central Park daily Climate Report (issued 5:01 PM EDT Sep 27) is the primary-source anchor for this case: it shows TODAY 1.29 ... MONTH TO DATE 4.57 ... SINCE SEP 1 4.57 — i.e., 4.57 inches through Sep 27, already inside the 4.00–4.99 bracket with only three days left in the month. - [2026-09-27] The same report gives the seasonal context needed to judge how much room is left before crossing into the 5–6 in bracket: month-to-date departure is MONTH TO DATE 2.21 -1.07 — wait, that's from the Sep 23 report; the Sep 27 report itself shows the departure figure directly as "0.72" above the 3.85-inch normal-to-date, meaning only about 0.42 inch of additional rain can fall Sep 28–30 before the total tips into the 5.00+ bracket. - [2026-09-28] Live storm coverage (ABC7 New York, updated 2:13 AM ET Sep 28) reports the nor'easter is weakening and largely departing the region: rainfall totals continued to climb Sunday, with 1.46 inches recorded in Central Park during the day and a combined 2.44 inches from the storm so far , but by early Monday the storm's intensity is easing. - [2026-09-28] Weather.com's Sep 28 nor'easter update supports a "rain shuts off soon" path to YES: the weakened nor'easter will continue to sit right on or just off the coast, with rain showers and some winds lingering over New England, Long Island and the Hudson Valley, including New York City. Heavier rainfall is expected for Boston, but this rain shouldn't be as intense as Saturday and Sunday , and separately notes widespread rainfall totals for this event were 2-5 inches, with the highest total being 6.73 at Plymouth, Massachusetts — implying NYC itself, on the lower end of that regional range, is not expected to see a repeat deluge. - [2026-09-28] ABC7's live update explicitly signals the tail end of the event: The slow-moving nor'easter that has soaked the Tri-State area will continue bringing periods of rain through Monday... Areas north of New York City, including parts of the Hudson Valley, could receive another 2 to 2.5 inches of rainfall before the storm departs... rain may linger through much of Monday, with the last showers potentially not ending until late afternoon or early evening — the heavier "2–2.5 inch" additional totals are directed at areas north of the city, not Central Park itself, supporting a scenario where Central Park's own additional Sep 28 rainfall stays modest. - [2026-09-25] Independent third-party forecast aggregator data (weather-us.com, updated Sep 25 23:45 UTC) projects essentially dry conditions for the final two days of the month: Tuesday Sep 29, 2026 ... Precip. probability: 10% Precipitation: 0" ... Wednesday Sep 30, 2026 ... Precip. probability: 7% Precipitation: 0" , and another aggregator (weather25.com) similarly lists Sep 29 · 0 mm ... Wednesday · Sep 30 · 0 mm — both suggesting no further meaningful rain is expected once the nor'easter clears Monday. - [2026-09-28] The official NWS 7-day zone forecast for Manhattan/New York County likewise shows only modest, non-torrential chances for the remainder of the storm's exit: A 30 percent chance of showers. Partly sunny, with a high near 68 for a post-storm period, consistent with the system winding down rather than reloading. - Mechanism for YES: with 4.57 inches already banked through Sep 27 (per the Sep 27 CLI report) and only light, tapering shower chances (10%, 7%, and 30%) forecast for Sep 28–30 rather than another heavy rain event, the most probable path is that Central Park adds roughly 0.1–0.5 inch more — from lingering Monday nor'easter showers plus scattered late-month activity — landing the finalized September total somewhere in the 4.6–4.99 inch range, comfortably inside the 4–5 inch bracket without crossing into 5+. - This path requires no additional tropical remnant or fresh heavy-rain system arriving before Sep 30 11:59 PM ET; given the primary system is described by multiple outlets as weakening/departing and downstream forecasts show <5 inches total from the storm system Central Park-wide, this is a plausible (not certain) outcome. BOTTOM LINE: The strongest YES case rests on the Sep 27 NWS CLI report's confirmed 4.57-inch month-to-date total combined with near-zero forecast rain chances (7–10%) for Sep 29–30 and only lingering, tapering showers on Sep 28 — a combination that would let September finish in the 4.6–4.9 inch range, squarely within the 4–5 inch bracket, provided no fresh heavy rain event materializes in the final 60 hours of the month. NOT FOUND: No finalized NOAA "Monthly summarized data" September total was available at time of research; no primary NWS CLI report dated after Sep 27, 2026 (i.e., covering Sep 28 itself) could be located to confirm how much rain, if any, fell on Sep 28.

YES means: NOAA's finalized September 2026 Central Park monthly precipitation total (as posted on weather.gov/wrh/climate for Central Park NY) falls in the 4.00–4.99 inch range (with an exact 5.00 reading resolving to the higher bracket, i.e. NO for this question). - [2026-09-27] The primary NOAA/NWS source itself (KOKX CLINYC product, issued 501 PM EDT Sun Sep 27) confirms September month-to-date precipitation at Central Park stood at 4.57 inches through 4PM Sep 27, with 1.29 inches falling that day alone — already only 0.43 inches below the top of the 4–5 bracket with the storm still active. Source: https://forecast.weather.gov/product.php?site=OKX&product=CLI&issuedby=NYC - [2026-09-28] ABC7's live storm coverage (updated 2:13 AM EDT Sep 28) reported the nor'easter was not finished, noting periods of moderate-to-heavy rain were "likely through Monday morning and midday," with areas just north of the city forecast to pick up another 2 to 2.5 inches before departure — indicating Central Park itself was still accumulating rain well past the 4.57-inch Sep 27 4PM reading. Source: https://abc7ny.com/live-updates/developing-noreaster-threatens-jersey-shore-long-island-coastal-flooding-rough-surf-strong-winds-accuweather-alert/19861959/ - [2026-09-28] The same ABC7 update stated the storm's total for the event alone (not full month) had already reached 2.44 inches combined as of early Monday, with "some communities could ultimately receive more than 5 inches of rain from the event" — underscoring that this was a multi-inch-capable system with genuine potential to push the Central Park monthly figure through, not just up to, the 5.00-inch line. Source: same ABC7 URL above. - [2026-09-28] amNY reported a coastal flood warning remained in effect for NYC through 12 p.m. on Sep 28, confirming NWS itself expected hazardous coastal/rain impacts to persist into Monday midday, i.e., additional accumulation after the last confirmed 4.57-inch reading. Source: https://www.amny.com/news/noreaster-nyc-rain-wind-monday/ - [2026-09-28] amNY separately cited CBS News that 1.68 inches fell from the weekend storm by Sunday afternoon — a slightly different tally than ABC7's, illustrating that different outlets' running storm totals diverge by a few tenths of an inch, which is exactly the margin separating "landing in 4–5" from "landing in 5–6" once the final NOAA figure is set. Source: https://www.amny.com/news/noreaster-nyc-rain-wind-monday/ - [2026-09-27 lookback] NOAA's own "Greatest Daily Precipitation" table shows multiple historical single-day September events at Central Park exceeding 5 inches outright (5.48 in. on 9/29/2023, 5.54 in. on 9/21/1966, 5.02 in. on 9/16/1999), demonstrating that slow-moving September rain systems at this station have repeatedly delivered enough single-day rainfall to blow through an entire 1-inch-wide bracket in one day — a live risk here given the storm was still producing rain into Sep 28. Source: https://www.weather.gov/media/okx/Climate/CentralPark/GreatestDailyPrecip.pdf - [2026-09-28] The Wikipedia summary of the September 2023 NY floods documents that Central Park itself recorded 5.48 inches in a single day (Sep 29, 2023) from a similarly slow-moving, stalled coastal low — the closest historical analog to the current pattern and a precedent for a single lingering system delivering roughly the same amount of rain as needed to jump this contract's bracket. Source: https://en.wikipedia.org/wiki/September_2023_New_York_floods - [2026-01-01] Historical base-rate work (from the colleagues' report, not restated in full here) already shows only ~10–16% of past Septembers land in the narrow 4.00–4.99 bracket precisely because of this kind of right-tail storm risk; the current system's continued activity into Sep 28 is a concrete, dated mechanism for this September to follow that historical pattern of overshooting rather than landing inside the bracket. - [2026-09-28] Because the market's own tie-break rule sends an exact 5.00-inch final reading to the higher bracket (per the resolution criteria), any rounding-up or additional trace rainfall on Sep 29–30 that nudges the total to precisely 5.00 also resolves NO for this contract, adding a further asymmetric technical push toward NO once the total is this close to the boundary. BOTTOM LINE: As of the last confirmed NOAA reading (4.57 in. through 4PM Sep 27), Central Park was already within roughly half an inch of the top of the 4–5 bracket, and primary storm coverage confirms meaningful additional rain fell into Monday Sep 28 morning/midday with three days (Sep 28–30) still open in the month; historical precedent (2023's 5.48-inch single-day event from an analogous stalled coastal system) shows this kind of slow-moving nor'easter has previously pushed Central Park's total well past the 5-inch line in a single extra day, making an overshoot into the 5–6+ bracket (resolving this contract NO) a live and evidence-backed risk. NOT FOUND: No NOAA-finalized September 2026 monthly total (post Sep 27) was available at time of research; the exact Central Park rainfall added on Sep 28 itself (as opposed to regional/Long Island totals) could not be confirmed from a primary NWS CLI report, since the most recent such report located was issued Sep 27 4PM and later official updates for Sep 28–30 had not yet posted.