ModelBuilder model to classify Koppen Climate classification

I am trying to see which area in the United States falls into which category of Koppen’s climate zones.

Right now, I am working on B climates, using Raster Calculation.
The attached is a screenshot of my ModelBuilder.

PRISM_tmean is a raster data of average annual temperature in US, and PRISM_ppt is a total of annual average precipitation.

What I am struggling with is that now I want to use Con tool to say "if 70% of annual precipitation falls in summer half months (from April to September), use the Summervalue.

How can I use Con tool to do this?

I have raster data of average precipitation for all months as well.