The 18th and penultimate round of the 2015 Formula One World Championship, the Brazilian Grand Prix, is currently underway at São Paulo’s Autódromo José Carlos Pace, or Interlagos as the fans refer to it. The weather can be tricky here, as there is often high heat and torrential rain. For instance, last year, the hottest track temperatures recorded all season were in Brazil, and this year there might be some rain during the weekend.

The good news is that Sunday’s forecast is for cloudy skies but no rain, though the weather in Brazil can be quite changeable. The peak temperature on the day will be 74 degrees F (23 degrees C) and wind speeds should be low.

At 2.6 miles in length, Interlagos is one of the shorter circuits on the calendar, but it’s tough on the cars and drivers alike. Resurfacing of the circuit last year has lessened the abrasion levels slightly, meaning it’s slipperier than usual. All these varying factors make Pirelli’s nomination of its versatile medium and soft tire compounds an ideal choice.

Despite plenty of partying back home in Monaco and even a car crash in his Pagani Zonda a few days ago, the world champion Lewis Hamilton appeared completely unfazed during today’s practice session. The Mercedes AMG driver set the fastest time, with the gap between him and the next best driver, fellow Mercedes driver Nico Rosberg, coming in at more than half a second. Ferrari’s Sebastian Vettel was the third fastest.

Going into tomorrow's qualifying and Sunday’s race, Hamilton leads the 2015 Drivers’ Championship with 345 points. Rosberg is in second with 272 points, while Vettel is in third with 251 points. In the Constructors’ Championship, Mercedes sits on a massive 617 points while Ferrari is second with 374 points and Williams is third with 243 points.

_______________________________________

Follow Motor Authority on Facebook and Twitter.