From Nookipedia, the Animal Crossing wiki

This month's events

In New Horizons
24th Bug-Off
(northern hemisphere)
25th Snow completely melts
(southern hemisphere)
In previous games

Menu Nook Shopping NH Icon.png Nook Shopping events

Rodeo-Style Springy Ride-On NH Icon.png Cowboy Festival
Jul 15th — Aug 15th
Orihime Outfit NH Icon.png Cowherd & Weaver Girl Day
Aug 1st — Aug 10th
Cucumber Horse NH Icon.png Obon
Aug 10th — Aug 16th
Tomato Festival Tee NH Icon.png Tomato Festival
Aug 20th — Aug 31st

Menu Critterpedia NH Icon.png Critters in New Horizons

August critters in New Horizons
Bug NH Icon cropped.png Bugs Fish NH Icon cropped.png Fish Sea Creature NH Icon cropped.png Sea creatures
New in the northern hemisphere Northern Hemisphere icon.png
Soft-shelled turtle
Moray eel
migratory locust
rice grasshopper
Walker cicada
New in the southern hemisphere Southern Hemisphere icon.png
tiger beetle