The MetOp-B satellite was launched atop a Soyuz rocket late Sunday night, with the spacecraft separating from the rocket and achieving orbit about 500 miles above the Earth.
The satellite joins its predecessor MetOp-A, launched in 2006, to provide data critical for computer models that are relied on for daily forecasts.
"Now, you could not imagine predicting the weather without satellites," Alain Ratier, the director general of Eumetsat, the intergovernmental organization charged with running Europe's weather platforms, told BBC News.
MetOp-A and B will circle the Earth from pole to pole in formation, which will allow cross-checking of their data ahead of eventual reliance on just MetOp-B, as the MetOp-A spacecraft is operating beyond its design lifetime, officials said.
Both satellites are equipped with exactly the same instrument package, they said, able to record a large number of atmospheric measurements.