Perth has had its hottest pair of days since March, but thunderstorms are taking over as the dominant weather feature until Wednesday. The mercury reached 35 degrees on Sunday before a brief late evening storm. On Monday, the temperature made it to 34 degrees by 12:30pm with time for more heating. Tuesday and Wednesday will then be cooler. Meanwhile, thunderstorms are only a low risk this afternoon for the western capital before the risk increases on Tuesday and Wednesday. A low pressure trough sitting offshore has been drawing hot easterly winds over the west coast. This trough will move onshore during the next few days, bringing enough instability for thunderstorm activity. Showers and storms are likely to bring between 5-10mm to Perth by Thursday morning. Some parts of Perth should gain more than that with thunderstorms. From Thursday, showers will ease and clear as the trough moves east into South Australia. This will allow a high pressure ridge to provide sunny skies for the rest of the week.