Outdoor gatherings have picked up across the city as temperatures climb into the high 80s this week. At a backyard birthday in Carroll Gardens on Saturday, hosts set out platters of marinated mozzarella balls and bowls of seasoned popcorn. These dishes, assembled in advance, kept things easy for both kitchen staff and home cooks.

Neighborhood caterers report growing demand for unfussy, portable snacks. At Eataly Flatiron, pre-skewered caprese and jars of pickled vegetables have become standard party orders. Small plates that hold up well in the heat—such as chickpea salad cups and spiced nuts—are showing up at rooftop bars from Bushwick to Tribeca.

The focus is on ingredients that do not wilt or sweat on a buffet. "People want things that can sit out for a bit," said Luis Moreno, manager at Greene Grape Provisions, who notes that spicy popcorn and cheese-stuffed peppers have been moving quickly this month.

For hosts, the goal is often to minimize last-minute prep. "No one wants to be stuck in the kitchen during a heatwave," said event planner Shira Cohen, who favors trays of crudités and dips for Saturday evening cocktail parties. With July Fourth gatherings approaching, expect to see more simple, make-ahead appetizers on picnic tables and apartment stoops.