Rain has hindered any worthwhile data gathering as Fernando Alonso went quickest in the opening practice for the Spanish Grand Prix.
As many teams led by McLaren rolled out serious upgrade packages at the Catalunya circuit, Alonso topped the session ahead of his Ferrari team-mate Felipe Massa.
Alonso clocked 1:25.252s, .203s quicker than Massa with Jean-Eric Vergne (Toro Rosso) grabbing the third best time on slicks as the track dried out.
The heavily updated McLarens did not show their hand in the unfavourable conditions, with Jenson Button turning six untimed laps.
Practice 1
| 1 | Fernando Alonso | Ferrari | 1m25.252s | 20 |
| 2 | Felipe Massa | Ferrari | 1m25.455s | 20 |
| 3 | Jean-Eric Vergne | Toro Rosso-Ferrari | 1m25.667s | 25 |
| 4 | Romain Grosjean | Lotus Renault | 1m26.042s | 21 |
| 5 | Adrian Sutil | Force India-Mercedes | 1m26.212s | 24 |
| 6 | Lewis Hamilton | Mercedes | 1m26.374s | 19 |
| 7 | Valtteri Bottas | Williams-Renault | 1m26.456s | 20 |
| 8 | Kimi Raikkonen | Lotus-Renault | 1m26.614s | 21 |
| 9 | Nico Rosberg | Mercedes | 1m26.621s | 21 |
| 10 | Paul di Resta | Force India-Mercedes | 1m26.755s | 16 |
| 11 | Daniel Ricciardo | Toro Rosso-Ferrari | 1m26.940s | 26 |
| 12 | Nico Hulkenberg | Sauber-Ferrari | 1m27.061s | 24 |
| 13 | Sergio Perez | McLaren-Mercedes | 1m27.135s | 6 |
| 14 | Esteban Gutierrez | Sauber-Ferrari | 1m27.250s | 26 |
| 15 | Pastor Maldonado | Williams-Renault | 1m27.576s | 24 |
| 16 | Giedo van der Garde | Caterham-Renault | 1m28.600s | 19 |
| 17 | Jules Bianchi | Marussia-Cosworth | 1m28.887s | 14 |
| 18 | Heikki Kovalainen | Caterham-Renault | 1m29.177s | 14 |
| 19 | Sebastien Vettel | Red Bull-Renault | 1m29.457s | 11 |
| 20 | Mark Webber | Red Bull-Renault | 1m29.473s | 21 |
| 21 | Rodolfo Gonzalez | Marussia-Cosworth | 1m30.314s | 12 |
| 22 | Jenson Button | McLaren-Mercedes | no time | 6 |
