Most items are not heat sensitive and can ship anytime. 

Heat Sensitives needing cool ship over 80° F (26°C)

See Also: 1. Heat Sensitive 2. Heat Maps 3. Ship Time 4. Cool shipping

All Chocolates, M&M's, rainbow mix, giant mints and chocolate babies. 
        (When over 70°F (21°C) No Lindt Truffles)
Confections, yogurt & carob confections, baking drops and coatings, smooth and melty mints, confetti drops, sweet and salty mix,  Neapolitan coconuts, coconut bonbons and haystacks. Unwrapped: Lemon drops, horehound, cinnamon balls and licorice babies.

 Heat sensitives needing cool ship over 90°F (32°C)

Medjool dates, date rolls, cherry sours, cinnamon imperials, Reese's pieces, sugar free hard candy, candy corn,  jolly ranchers and jelly beans but NOT Jelly Belly jelly beans.

No heat sensitive items to southern states during June, July, and August.  
Southern States: Florida, Louisiana, Texas, New Mexico, Arizona, Nevada and California. 

Typically it's above  80°F/26°C during June, July and August in the US.
Southern States are also typically above 80°F during May and September.