All Hatch Charts
Oldman River near Lethbridge
Southern Alberta · 5 active this month
Oldman River near Lethbridge Hatch Calendar
Last reviewed 2026-05-21
May hatches
No photo available
Little Black Stonefly
Capniidae
Moderatemedium
#16-206-10 mm
Air 5–18°CWater 2–8°C
Brown Dun
Ameletus spp.
Moderatemedium
#14-1610-15 mm
Air 12–22°C (optimal 14–20°C)Water 8–14°C (optimal 9–13°C)
Midge
Chironomidae
Highmedium
#18-263-12 mm
Air -5–25°C (optimal 5–18°C)Water 2–20°C (optimal 4–15°C)
Blue-winged Olive
Baetis spp.
Highmedium
#18-225-7 mm
Air 8–18°C (optimal 10–16°C)Water 5–12°C (optimal 6–11°C)
No photo available
Grannom
Brachycentrus occidentalis
Highmedium
#14-1610-14 mm
Air 10–22°CWater 6–14°C