Heavy showers and even a hailstorm had hit the Nuerburgring on Thursday but despite the usual threatening clouds in the Eifel mountains, the teams were able to get through their warm up routines with different tyres undisturbed.
World champion and championship leader Sebastian Vettel topped the timesheets for much of the session at his home race but dropped down to third behind Red Bull team mate Mark Webber and Spain's Alonso, who set the fastest lap of 1:31.984.
Toro Rosso's Sebastien Buemi suffered the only big incident when he spun off late in the session while Michael Schumacher ploughed through the gravel.
Spanish Grand Prix
Alonso focused on speed not struggles ahead of home return
A decent crowd, which had earlier clogged the roads in the isolated area of western Germany, was in attendance with Force India reserve driver Nico Hulkenberg taking the first session instead of Paul Di Resta meaning seven Germans were on track.
McLaren's Lewis Hamilton led during the early exchanges but ended up over a second behind Alonso in fifth while Indian Karun Chandhok struggled for pace in the Team Lotus having been given the drive in place of Jarno Trulli on Thursday.
Formula 1
Grosjean to test Hamilton's 2019 Mercedes at French GP circuit
Portuguese Grand Prix
Race review: Hamilton and Mercedes flex mental muscles, Alonso shows promise
03/05/2021 AT 09:33