Rain in Paris on Sep 3, 2027? — Above 0 millimeters

- [2027-09-03] The contract's date is about 10.5 months away. No observation or usable forecast exists yet. Any outcome rests on climatology plus the settlement mechanics. https://weather.com/kalshi - [2026-10-14] The public weather.com/kalshi page, rendered today, shows only hourly METAR temperatures for Oct 12–13, 2026. It had no daily precipitation total, no LFPG precipitation field and no Sep 2027 data. The source is "METAR airport observations relayed via The Weather Company". The page describes Preliminary, Revised and missing hours. This is a different data type from the Météo-France daily precipitation the rules cite. I could not confirm how the precipitation value is displayed. https://weather.com/kalshi - [2026-10-05] Météo-France's 3-month outlook for Oct–Dec 2026 favours a warmer-than-normal quarter. It also favours a wetter-than-normal quarter over most of mainland France, except the Southeast. Météo-France says these outlooks give no day-by-day detail. They are less skilful for precipitation than for temperature. The outlook does not reach Sep 2027. https://meteofrance.fr/actualite/publications/les-tendances-climatiques-trois-mois - [2026-09-25] Meteo-paris.com described weeks of dry, abnormally warm weather in France. It said a change to rain was possible in early October, with models still diverging. https://www.meteo-paris.com/actualites/debut-octobre-la-meteo-pourrait-brutalement-basculer-vers-l-automne-en-france - [2026-09] The weatherandclimate.eu monitor (Paris station 07156, not LFPG) showed Sep 2026 with about 0.6 mm total through Sep 20, against a 45 mm normal. Sep 3, 2026 was 0.0 mm. Most days in that stretch were dry. https://www.weatherandclimate.eu/monitor/07156 - [Undated, climatology] WeatherSpark gives the chance of a wet day at LFPG (≥0.04 in, about 1 mm) as 22% on Sep 1, rising to 25% by month's end. https://weatherspark.com/m/147948/9/Average-Weather-in-September-at-Paris-Charles-de-Gaulle-Airport-France - [Undated, climatology] Other sources give Paris September rainy-day counts that depend heavily on threshold. Weather-atlas gives 9.3 days. Weather-and-climate.com gives about 12 days at >0.2 mm and 52 mm for the month. Wanderingweather gives about 48% of days with measurable rain. Pageweather gives about 9 days at ≥1 mm. These imply roughly 30–45% of days with any measurable rain. Trace amounts count as 0. https://weather-and-climate.com/Paris-September-averages - [2026-08-27] Kalshi moved its daily temperature series to The Weather Company as the settlement source. A third-party guide says precipitation contracts still settle on NWS. That conflicts with this contract's rules, which name The Weather Company's Météo-France-attributed LFPG daily value. The contract's own rules govern. https://www.turbinefi.com/blog/how-to-trade-kalshi-weather-markets-2026 - [2026-10-14] Wethr.net's daily-rain dashboard tracks LFPG (Paris CDG) for Kalshi and Polymarket daily rain markets. This shows that similar daily-rain contracts exist, including a 'Where will it rain today?' series. https://wethr.net/daily-rain BOTTOM LINE: There is no current-state information for 3 Sep 2027. The outcome depends on September climatology, with roughly a 30–45% chance of any measurable rain on a given day depending on source and threshold. The settlement-source quirks are the other factor: the reporting day runs 06:00–06:00 UTC, trace amounts count as 0, and missing values count as 0, all of which lean toward No. NOT FOUND: The weather.com daily precipitation field for LFPG (only hourly temperatures were visible). Any Météo-France seasonal outlook covering Sep 2027. Any LFPG-specific daily station climatology from Météo-France. Sibling Kalshi Paris rain contracts and their dates.

- [2026-10-14] Wikipedia's "Climate of Paris" page gives Météo-France 1991–2020 normals. Orly (the closest official station on that page to CDG) has 7.7 days with ≥1.0 mm in September, which is about 26% of days, and 47.4 mm for the month. Parc Montsouris has 7.5 such days and 44.7 mm. The >0 mm threshold is looser than ≥1 mm, so the YES frequency should be clearly higher than 26%. https://en.wikipedia.org/wiki/Climate_of_Paris - [2026-08-28] OddsShopper's explainer says Kalshi rain markets settle on The Weather Company's value. A trace counts as 0 and a missing value counts as 0, so both resolve No. Revisions after expiry do not change the outcome. Pure drizzle can therefore resolve No, which pulls YES below the raw "any rain" frequency. The piece describes the US NWS-station rain markets; the contract text given to me says the same about trace and missing values. https://www.oddsshopper.com/articles/prediction-markets/kalshi-rain-markets - [2026-10-14] climate-data.org (modelled data, Paris generally, not CDG) gives a daily mean for 3 September of 3.4 mm. It puts September at 51 mm and about 6 rainy days, and calls it the driest month. This is a monthly-average-style figure, not a frequency of days above 0. https://en.climate-data.org/europe/france/ile-de-france/paris-44/t/september-9/ - [2026-08] Other travel-climate sites disagree on September rainy days. Counts run from about 8 days (>0.1 mm, 47 mm, weathermonth.com) to about 9 days (≥1 mm, 60 mm, Open-Meteo 2015–2026, pageweather.com) and 12 days (weather-and-climate.com). The thresholds differ, so these are not comparable. Rain days above a trace threshold are roughly 8–12 of 30, which is about 27–40%. https://www.pageweather.com/weather/paris/september - [2026-10-14] WeatherSpark's CDG page gives average September rainfall of about 1.5 in (about 38 mm). Its 2024 daily log shows rain observed at CDG on 3 September 2024, which is one anecdotal year. https://weatherspark.com/h/m/147948/2024/9/Historical-Weather-in-September-2024-at-Paris-Charles-de-Gaulle-Airport-France - [2026-09] Kalshi's international cities (London, Paris and others) settle on The Weather Company with no NWS station. Kalshi's temperature series moved to The Weather Company in August 2026. This is a settlement-source detail, not a rain base rate. https://apify.com/perchpermits/kalshi-weather-markets-nws - [2026-10-14] The wethr.net dashboard lists Paris-area stations for Polymarket and IBKR rain markets: LFPB Le Bourget and LFPO Orly. It does not list LFPG for Kalshi. Those are sibling markets on other stations, and I found no prices or history for them. https://wethr.net/rain BOTTOM LINE: The reference class is a single September day at a Paris airport. About 25–30% of days reach ≥1 mm, and some 35–45% likely register >0 mm in a station's daily total (my inference, not a sourced figure). The trace-equals-zero rule trims YES at the margin. That points to a base rate somewhat below 50%, and no skill-bearing forecast exists this far out. NOT FOUND: A CDG-specific (LFPG) count of days with >0.0 mm in early September from Météo-France, or the daily series as The Weather Company reports it. I also found no multi-year tally of past 3 September outcomes at CDG, and no sibling Kalshi or Polymarket Paris rain market prices.

YES means: The Weather Company's LFPG (Paris CDG) daily precipitation total for the 06:00 UTC Sep 3, 2027 to 06:00 UTC Sep 4 reporting day is strictly above 0.0 mm. A trace or a missing value counts as 0. - [2026-10-14] Météo-France's 1991–2020 normals for Roissy-CDG (via Wikipedia, which cites Météo-France) give September 50.0 mm and 7.9 days with ≥1 mm. That is slightly wetter than Orly or Montsouris. CDG, which is the settlement station, is the wetter of the Paris-area stations. The same table shows about 116 days a year with ≥1 mm. https://en.wikipedia.org/wiki/Roissy_en_France - [2026-10-14] The >0 mm threshold sits well below the ≥1 mm threshold. The WeatherSpark CDG page counts a "wet day" at ≥0.04 in (about 1 mm) and gives rain on about 7.1 days in September. That count excludes trace and drizzle days. Infoclimat's CDG daily log for September 2022 shows many days with 0.2–1.6 mm that a ≥1 mm count misses. Examples are 0.4 mm on Sep 1, 0.2 mm on Sep 13 and 0.8 mm on Sep 16. The measurable-rain frequency is therefore well above the ≥1 mm figure. The page returned 403 to me on a direct fetch, so these values come from the search snippet. https://www.infoclimat.fr/climatologie-mensuelle/07157/septembre/2022/roissy-charles-de-gaulle.html - [2026-10-14] The reporting day spans 24 hours from 06:00 UTC, not a civil day. A showery or frontal system arriving at any point in that window, including the early-morning hours of Sep 4, counts for Sep 3. Spreading the exposure over two civil days slightly raises the chance that some measurable rain lands inside the window. This is mechanism, not a sourced statistic. https://weather.com/kalshi - [2026-10-14] Wethr.net lists LFPG Paris among the ~36 stations in Kalshi's daily "Where will it rain today?" series, alongside LFPB and LFPO. A liquid LFPG rain contract therefore exists in the same family as this one. Wethr describes its resolution as based on NWS CLI with trace as NO, which is the US-station wording and does not apply to LFPG. https://wethr.net/daily-rain/lfpg - [2026-10-14] CPC's discussion, dated about Oct 8, expects a strong-to-very-strong El Niño through Jan–Mar 2027 at greater than 83% likelihood. It also expects ENSO-neutral by Apr–Jul 2027. The IRI of Sep 21 gives 61% El Niño odds by mid-2027. A decaying El Niño has no established link to September rain in Paris. CPC itself says impacts are "not guaranteed". This gives no skill for Sep 3, 2027. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml - [2026-10-14] A dated anecdote supports the "early September can be wet" case. Infoclimat's event list for CDG notes a rain, wind and thunderstorm episode on 4–5 Sep (2026 listing context, exact year not shown). Weak evidence: nothing is shown for Sep 3, 2027. https://www.infoclimat.fr/climatologie/normales-records/1991-2020/roissy-charles-de-gaulle/valeurs/07157.html - [2026-10-14] The Infoclimat Sep 2022 log shows Sep 3, 2022 at 0.0 mm at CDG. That is one dry sample for the date, so early-September dry spells occur. The 2024 WeatherSpark log in the earlier report shows rain on Sep 3, 2024. Single years prove nothing. https://www.infoclimat.fr/climatologie-mensuelle/07157/septembre/2022/roissy-charles-de-gaulle.html - [2026-10-14] The strongest path to YES: an Atlantic frontal band or a convective shower or thunderstorm cell crosses the Île-de-France at some point in the 24 h window. The CDG airport gauge must record at least 0.1 mm. Météo-France reports to 0.1 mm, so this threshold is lower than the US one. Early-September heat-driven storms are plausible. The prerequisites are a daily total of at least 0.1 mm, a non-missing value, and no downward revision before the initial value is taken. https://weather.com/kalshi BOTTOM LINE: The best YES case rests on CDG being the wetter Paris-area station (about 7.9 days ≥1 mm in September, ~50 mm). The 24-hour window straddles two civil days, and Météo-France's 0.1 mm resolution makes the >0 threshold far looser than the ≥1 mm counts, so the any-rain frequency is plausibly well above 26%. No seasonal signal or forecast for Sep 3, 2027 exists, so this stays a climatology argument. NOT FOUND: Any multi-year tally of CDG days with >0.0 mm on Sep 3 or in early September. A direct fetch of the Infoclimat CDG pages (403 blocked, so I only have snippets). The weather.com daily precipitation field for LFPG. Any seasonal outlook covering Sep 2027. Prices or history for sibling Paris rain markets.

YES means: The Weather Company's daily precipitation total for Paris CDG (LFPG), labelled 3 Sep 2027 (06:00 UTC to 06:00 UTC the next day), is strictly greater than 0.00 mm. - [2026-10-14] A date-specific "any rain" frequency is higher than the ≥1 mm counts, so the NO case rests on the roughly 55% of days that are dry, not on a low rain frequency. Extremeweatherwatch (1991–2020, Orly/Paris-area record) puts the September daily chance of precipitation at 43.7%. That means about 56% of days are dry, even before the trace rule removes borderline days. Its record station is Orly, not CDG. https://www.extremeweatherwatch.com/cities/paris/month-september - [2026-10-14] The ≥1 mm count is the cleaner NO anchor. The Montsouris 1991–2020 normal is 7.5 days of ≥1 mm rain in September, about 25% of days. That is the same figure as in the earlier report, here confirmed on a second domain updated 2026-10-10. The monthly total of 44.7 mm is low for Paris. Rain days are also fewer in September than in any other month on Wikipedia's Montsouris table, apart from July. https://donneesmeteo.fr/climat/paris - [2026-10-14] The "driest month" label cuts toward NO. Weather-and-climate.com calls September the driest month of the year at the CDG coordinates (52 mm against December's 77 mm), counting days above 0.2 mm. A day on 3 Sep sits in the seasonal dry trough. https://weather-and-climate.com/average-monthly-precipitation-Rainfall,Paris,France - [2026-08-28] The settlement mechanics make the ledger stricter than the sky. OddsShopper's explainer, which I fetched in full, says a trace is "defined as zero" and that visible drizzle can settle No. It adds that missing daily values also count as 0, so a reporting gap resolves the same way as a dry day. Revisions after expiry do not reopen the market. The piece covers US NWS-style stations, but the rule text for this contract says the same. https://www.oddsshopper.com/articles/prediction-markets/kalshi-rain-markets - [2026-10-14] The Météo-France daily value (RR) is 0.0 whenever the gauge reads under 0.1 mm, and the data pipeline can add gaps. The API documentation says it is archive-only, not real time, and daily data are refreshed from 11:30 UTC on day J. Type-5 stations are "not expertised", and availability of their data is occasional. Both effects push marginal days and gaps to 0.00, which resolves NO. https://confluence-meteofrance.atlassian.net/wiki/spaces/OpenDataMeteoFrance/pages/854261785/API+Donn+es+Climatologiques - [2026-10-14] The data chain has a quirk that favours NO. Kalshi's own help page says weather markets name their source in each market's rules. It says hourly temperature markets use The Weather Company. The public weather.com/kalshi page, per the earlier report, shows only METAR temperatures, with no daily precipitation field. If the daily field is absent or late at expiry, "missing counts as 0" applies. https://help.kalshi.com/en/articles/13823837-weather-markets - [2026-09-xx] Third-party coverage of Kalshi's precipitation contracts is inconsistent about the source. Turbinefi says rain and snow settle on NWS climate reports. This contract names The Weather Company with Météo-France attribution. That mismatch is a risk of procedural disputes or a fallback to a last-fair-price provision. It is not a directional source for YES. https://www.turbinefi.com/blog/how-to-trade-kalshi-weather-markets-2026 - [2026-10-14] The reporting window is 06:00–06:00 UTC, so it splits rain across two calendar days. Rain that falls on the evening of 2 Sep, or after 06:00 UTC on 4 Sep, does not count. The window also begins at 08:00 Paris time, so overnight showers in the early hours of 3 Sep Paris time (before 08:00) fall in the previous report day. The 24 h window is the same length as an ordinary day, so this is a shift and not a reduction in exposure. https://confluence-meteofrance.atlassian.net/wiki/spaces/OpenDataMeteoFrance/pages/854196251/API+Cibl+e+Clim+EN - [2026-10-14] Status quo: no information changes the dry default. There is no skilful forecast for a single day about 10.5 months out. Autumn 2026 seasonal tendency data, covered in the earlier report, do not reach September 2027. Climatology is the only usable prior, and it points to a dry day being more likely than a wet one. The 2026 September record (a dry, warm month, noted earlier) has no bearing on 2027. BOTTOM LINE: Dry days outnumber wet days in September at Paris-area stations: about 56% of days with no precipitation, and about 75% with under 1 mm. The contract's trace-equals-zero and missing-equals-zero rules add to that. The best NO case is a majority-dry base rate plus settlement mechanics that skew toward 0.00. NOT FOUND: An LFPG-specific count of 3 September (or early-September) days above 0.0 mm from Météo-France or The Weather Company. The daily precipitation field on weather.com/kalshi. Any prior-year weather.com daily totals for LFPG. A sibling Kalshi Paris rain contract and its price history. Météo-France's rounding rule for daily RR at LFPG, which I only inferred.