April 19, 2026 - April 20, 2026, the price of the 12°C option surged from 11c to roughly 27c, and the 11°C option jumped from 13c to 25c, while the 8°C option plummeted from 23.5c down to around 3c. This was caused by a major update in short-term weather forecasting models, projecting a warm front for Toronto on April 21 and significantly raising the expected high temperature.

Predicting the highest temperature of a specific city on a single day is a typical novelty/fringe market topic. Aside from local residents and weather data traders, the general public does not think about such granular questions.

April 19, 2026 - April 20, 2026, the Yes price for 21°C surged from 11.5c to 33.5c, and the Yes price for 19°C rose from 16c to 35c before settling back to 27c. This was likely driven by short-term weather forecasting models updating their expected peak temperatures as the resolution date approaches.

April 19, 2026 - April 20, 2026, the Yes price of 13°C surged from 18c to 40.5c because weather models converged, further confirming temperatures will not be as high as previously anticipated. April 19, 2026 - April 20, 2026, the Yes price of 15°C plummeted from 26.5c to 11c because the forecast of cooler air became more definitive, reducing the probability of higher temperatures.

Weather forecasting is a niche but established category in prediction markets (e.g., widely seen on Kalshi). While the general public rarely bets on the specific daily high temperature of a single city, it is a common data-driven market for weather enthusiasts and quantitative traders, making its novelty level moderate.

April 21, 2026 - April 21, 2026: The price for 12°C surged from 20.5c to 98.75c, while 11°C plummeted from 74.5c to near 0c, because actual temperature observations in Wellington reached 12°C later in the day, virtually locking in the market outcome. April 20, 2026 - April 20, 2026: The price for 11°C surged from 37.5c to 90c, as earlier actual temperature observations on the day indicated a highly likely maximum of 11°C. April 20, 2026 - April 20, 2026: The price for 12°C plummeted from 45c to 8.5c, as the likelihood of reaching 12°C dropped significantly with passing time and cooler actuals. April 19, 2026 - April 20, 2026: The price for 12°C rose from 29c to a peak of 56.5c before settling at 47c, as forecast models temporarily increased confidence in a 12°C high as the resolution date approached. Meanwhile, the 11°C option also increased from 14.5c to a peak of 38c, stabilizing at 30.5c, showing rising probability for cooler outcomes. April 19, 2026 - April 20, 2026: The price for 13°C plummeted from 30c down to 6.5c before bouncing slightly to 12c, reflecting meteorological data erasing the likelihood of higher temperatures.

April 19, 2026 - April 21, 2026, the price of '16°C' surged from 20.5c to 92c, while '17°C' plummeted from 32c to 8.5c, and '18°C' collapsed from 32c to less than 1c. This occurred because, as the resolution day arrived and real-time weather data became available, models confirmed the high temperature at ZSPD would be capped at around 16°C. The market rapidly dumped alternative options and heavily concentrated on 16°C. April 19, 2026 - April 20, 2026, the price of '15°C' surged from 10c to 34c, while '18°C' plummeted from a high of 32c to 4.5c. This occurred because, as the resolution date approached, weather forecasting models indicated a cooler trend for Shanghai Pudong Airport, causing the market to dump higher temperature options and consolidate around 15°C and 16°C. April 19, 2026 - April 20, 2026, the price of '16°C' steadily climbed from 26c to 43.5c, while '18°C' plummeted from a high of 32c to 11.5c, and '15°C' retreated from 25c to 12.5c. This occurred because weather forecasting models converged, confirming the high temperature would likely land in the 16°C-17°C range, prompting the market to dump outlier options.