Data is coming from PRISM National Weather data set.
COMET currently uses observed historical PRISM weather data, from the nearest weather station relative to the parcel defined, for all years in the baseline. We expect most users to set their baseline years to end the year before the current year. Assuming a user has full data for a 20+ year baseline end period, 2000-2023 weather included in the model run is the observed weather. COMET is not predicting any future weather patterns for the scenarios, which are on the timeline of 10 years following the end of the baseline, in the typical case, this would be years 2024-2033. Instead the weather from the last 10 years of the baseline are used for the next 10 years. For example, assuming a typical baseline 2000-2024, 2016 weather is used for 2026, 2017 for 2027, 2018 for 2028, etc...
So the weather that is used for the baseline and the future scenario is the same.