Hatch calendar pages cover species-specific temperature triggers and historical timing on specific rivers.
Freshwater Trout & Hatches
What water temperature triggers mayfly hatches?
Most mayfly hatches start when water temperatures hit species-specific thresholds: BWOs around 45-55°F, sulphurs at 55-65°F, green drakes at 60-65°F, tricos at 60-70°F. Sustained water temperature in the trigger range produces the heaviest emergences; brief temperature spikes don't.
More from Freshwater Trout & Hatches
- What is a hatch and why does it matter for fly fishing?
- When is the sulphur hatch on Eastern trout streams?
- What is the green drake hatch and why is it so famous?
- What is a Blue Winged Olive hatch?
- How do I match the hatch when trout are rising?
- What time of day do most hatches occur?
- What is a spinner fall and how do I fish it?
- What is the difference between a dry fly and a nymph?
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