A lot of sites will offer you a weather forecast for Ronda. However, they will base it on what the forecast is going to be in Gibraltar or Seville. Ronda, being in the mountains and not surrounded by sea usually has different weather to Gibraltar and Seville. For the day I went I was getting forecasts for daytime highs of 23 or 31oC. The temperature reported on board the Renfe service was 26oC on a train arriving at the hottest time of the day.