WEATHER · FORECAST CHANGE

Highest temperature in Philadelphia on Oct 31, 2026: PBE moves “65° to 66°” down to 11% from 22%

New forecast guidance reached the model between 17:00 UTC and 23:00 UTC on Oct 30. Same model version, later data cutoff: here is exactly which inputs changed.

Published October 30, 2026 at 23:03 UTCModel data as of Oct 30 23:00ZBy the PropBetEdge Predictions Desk1 min read

Photo: 颐园居 · CC BY-SA 4.0 · Wikimedia Commons

22%11%

65° to 66° · pbe-weather-maxtemp@1.1.0 · 17:00 UTC → 23:00 UTC

Move−11 pts

Market at capture2%

Inputs changed1primary

LIVE UPDATE · not part of the original story

Highest temperature in Philadelphia on Oct 31, 2026?

65° to 66° · PRE-WINDOW

PBE11%0 pts since publication

Kalshi2%0 pts since publication

Gap+9

RESEARCH PBE Oct 30 23:00Z · market

Open the live forecast →

Quick read

pbe-weather-maxtemp@1.1.0 moved “65° to 66°” from 22% to 11% (−11 pts).
Later data cutoff: Oct 30 17:00Z → Oct 30 23:00Z; same model version, so the move reflects inputs, not a model change.
Primary inputs changed: National Blend of Models forecast high.
The Kalshi mid captured with each snapshot went from 2% to 2%.

What changed in the inputs

Between the snapshot captured at Oct 30 17:00Z (data cutoff Oct 30 17:00Z) and the one at Oct 30 23:00Z (cutoff Oct 30 23:00Z), the same model version — pbe-weather-maxtemp@1.1.0 — moved “65° to 66°” from 22% to 11%. The model inputs that changed: National Blend of Models forecast high from 63°F to 62°F.

EVIDENCEStored model inputs, before and afterFrom the immutable feature snapshots attached to each forecast

Input	Before	After	Primary
Guidance lead time	17h	11h	—
National Blend of Models forecast high	63°F	62°F	yes

Units: as labeledAs of Oct 30 23:00ZSource: PBE feature snapshots

This page reports which stored inputs differ between two immutable forecasts. It does not claim why the underlying weather guidance changed.

The forecast path

PROBABILITY HISTORY“65° to 66°”: pbe-weather-maxtemp@1.1.0 snapshots vs the marketSame model version only; the dashed line is the stored Kalshi mid

Kalshi mid (stored observations)PBE pbe-weather-maxtemp@1.1.0 snapshots

Units: % probabilityAs of Oct 30 23:00ZSource: PBE forecast archive; Kalshi

Data table

Time (UTC)	Source	Value %
Oct 30 14:00Z	PBE pbe-weather-maxtemp@1.1.0	22
Oct 30 14:02Z	Kalshi mid	6
Oct 30 14:08Z	Kalshi mid	6
Oct 30 14:26Z	Kalshi mid	5
Oct 30 14:34Z	Kalshi mid	3
Oct 30 14:38Z	Kalshi mid	2
Oct 30 15:00Z	Kalshi mid	2
Oct 30 16:00Z	Kalshi mid	2
Oct 30 17:00Z	PBE pbe-weather-maxtemp@1.1.0	22
Oct 30 17:00Z	Kalshi mid	2
Oct 30 18:00Z	Kalshi mid	2
Oct 30 19:00Z	Kalshi mid	2
Oct 30 20:00Z	Kalshi mid	2
Oct 30 20:16Z	Kalshi mid	2
Oct 30 21:00Z	Kalshi mid	2
Oct 30 22:00Z	Kalshi mid	2
Oct 30 23:00Z	PBE pbe-weather-maxtemp@1.1.0	11
Oct 30 23:00Z	Kalshi mid	2

The Kalshi mid captured with each snapshot went from 2% to 2%.

The two snapshots

	Earlier	Later
Captured	Oct 30 17:00Z	Oct 30 23:00Z
Data cutoff	Oct 30 17:00Z	Oct 30 23:00Z
Guidance runs	NWS GFS MOS 2026-10-30T12Z, NWS National Blend of Models 2026-10-30T12Z	NWS GFS MOS 2026-10-30T18Z, NWS National Blend of Models 2026-10-30T18Z
PBE	22%	11%
Market at capture	2%	2%

Evidence & method

What this story is based on. Every value above was read from these immutable records.

65° to 66°

Model: pbe-weather-maxtemp@1.1.0 · RESEARCH
Snapshot: c56ce482-ffcd-423d-9914-9a2e7cd757ff
Compared with: c3b097be-9d36-4c05-861d-a4a6125c0963
Captured: Oct 30 23:00Z
Data cutoff: Oct 30 23:00Z
Market observation: 2% · captured with the snapshot
Source families: NOAA/NWS via Iowa Environmental Mesonet archive · NOAA Regional Climate Centers ACIS · NOAA/NWS api.weather.gov

RESOLUTION RULE

Resolves on: The Weather Company (weather.com/kalshi) — The Weather Company daily maximum temperature for CLIPHL (weather.com/kalshi)
Independent check: NWS Daily Climate Report CLIPHL (WFO PHI); NOAA RCC-ACIS USW00013739
Measurement: Maximum temperature for the climate day 2026-10-31, 00:00-24:00 local standard time (UTC-5)
Rounding: Whole degrees Fahrenheit as reported; preliminary values may differ by rounding/conversion
Exceptions: Preliminary data may be revised; the exchange may hold expiration until a non-erroneous revision, else last fair price

If the maximum temperature recorded at Philadelphia (CLIPHL) for Oct 31, 2026, is between 65-66° fahrenheit according to The Weather Company, then the market resolves to Yes.

MODEL LIMITATIONS

Pre-window only; no current-conditions input
Guidance can run cold/hot in unusual regimes (see LA diagnostic, 2026-10-04)

Weather · daily high — inputs: National Blend of Models day max (GFS MOS fallback) + station empirical guidance-error tables. This model on the research board →

Market prices are a benchmark only and never enter a PropBetEdge model. Research-stage probabilities; not advice.