Time series

Heating season in Poland: degree days, cold index and season cost (Sezon grzewczy finwire)

Daily finwire indices finwire_heating_season_index and finwire_heating_season_cost from IMGW-PIB synoptic stations (daily archive since 1966, current days from hourly readings, marked provisional): heating degree days since 1 July (Eurostat method: 18 C minus daily mean temperature on days with mean <= 15 C) vs the mean of the previous 20 full seasons (cold index, 100 = norm), for Poland (mean of 17 stations) and 17 cities; forecast of the season total with an 80% interval from the distribution of past winters (not a weather forecast), published only when the backtest on past seasons hits the interval at least 70% of the time and beats the naive "average season" forecast; season heating cost of a 100 m2 house for gas and heat pump (URE tariffs), coal and district heating (GUS); monthly means vs norm, season records, inland gas consumption (Eurostat). Aggregates only, no raw daily station readings.