If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Silvia: The hottest months are usually September and August, with an average temperature of 16°C, while the coldest months are August and July, with an average of 16°C. The rainiest months in Silvia are July, May, June and April, with each month seeing an average of 802 mm of rainfall.