The reading was a notch above the 4.4 percent flash estimate released by the statistics office earlier this month.
Polish GDP grew 4.7 percent in the first quarter of this year and expanded by 5.1 percent in 2018 as a whole, according to the Central Statistical Office.
Poland’s largest bank, PKO BP, estimated this month that the Polish economy would grow 4.6 percent in 2019, exceeding many predictions.
The bank also revised upward its projection for Polish GDP growth in 2020.
The European Commission, the executive arm of the European Union, last month raised its forecast for Polish economic growth this year to 4.4 percent, up from a May projection of 4.2 percent.
International rating agency Fitch in June upgraded its projection for Poland's GDP growth this year to 4.2 percent from a previous forecast of 4 percent.