The Analog Builder finds past seasons whose climate drivers most closely match a state you describe, then averages what those seasons delivered to every county in the lower 48. Choose any mix of ENSO (RONI or the ENSO event peak), the PDO, SOI, QBO, PNA, AO, NAO, EPO and WPO, for any of the twelve 3-month windows or the full October–April winter.

County temperature and precipitation come from NOAA/NCEI's nClimDiv county monthly record. Precipitation is shown as a share of each county's normal and temperature as a departure in °F. Each driver is standardized by its own spread before matching, so a large QBO swing and a modest ENSO swing count comparably, and the closest seasons since 1950 form the composite. A remove-trend option subtracts each county's long-term warming so the map shows the driver signal rather than the decade the analogs came from.

Confidence reflects how far the composite sits from normal given the county's year-to-year spread and the number of analogs; it does not prove the drivers caused the result. In our testing, ENSO carries the most useful skill for winter precipitation, while the AO and NAO dominate temperature but cannot be forecast far ahead. See the Composite Maps for gridded ENSO and MJO patterns and the Seasonal Outlooks for current model forecasts.