Question: How long does it take for lava to cool once it has erupted?

Claudia Krehl answered on 22 Mar 2013:

Incredibly long actually. When lava flows out of a volcano it has a temperature of about 1200 degrees celsius. Scientists measured the temperature of lava after it had traveled from the volcano to the sea and it was only 10 degrees cooler. And that was after travelling for 10 km! Pretty impressive. It is believed it can take several months for lava to cool down completely and if it leaves thick pools it can even take years. Luckily the outside of the lava flow cools very quickly and forms a crust that we could walk on after 10 to 15 minutes. Though I am not sure I would be the first to try!