If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Silvia: The hottest months are usually September and August with an average temp of 61°F, while the coldest months are August and July with an average of 61°F. The rainiest months in Silvia are July, May, June, and April, with each month seeing an average of 32 inches of rainfall.