Summer speed difference from spring

[920Bassin]

Hey guys!! Fun fishing I usually cruise at 50-60mph. Anyways, I have a 2018 920 with 18 Pro XS, 10inch Atlas running turning 25 Fury. In the spring i was getting 74-77 mph at about 6k rpms via GPS. Now with the humidity and heat I'm seeing 68-69 mph at about 5600rpms same setting as what I was running in spring. You guys seeing that much lost of speed in this summer heat/humidity?

[HLG]

im running the same setup as you except with the manual jack plate and im still seeing 74 consistently down here

[duncankopprichardson]

A couple mph sounds ok but not 9

[cdporchejr]

I agree with above, 8-9 mph loss seems like a lot. I am still running 74-75 in this summer heat.

[dannov5]

I run a 2012 721 with 250 Pro XS and have two props. A 27 Tempest for cooler months and a 26 Tempest Plus for the summer. The pitch change is more helpful for the hole shot during summer, but runs about 4mph slower.

[Jaytime25]

I am running 78-79 with 2 guys in and empty livewells but full tournament load and dual talons. Cooler days I’m in low 80’s