Mercury 25W40 Oil Temperature

[Kevin23]

Hi all, was just thinking about taking the boat out for some winter saugers this weekend and for some reason oil popped into my head out of the blue. Then I realized I have the factory 25w40 oil in my 90 4s since I wasn't planning on doing an oil change until spring. I've been doing some searching online and the only temperature rating I can find is to not use it below 40F stated on some forum. Is this accurate? Is that 40F air temp or 40F water temp? Am I safe at right around 40F air temp, as in low 40's, and 32-33 deg water temp?

Manual says:
Mercury or Quicksilver NMMA FC‑W or NMMA FC‑W catalyst compatible
certified SAE 10W‑30 4‑Stroke Marine Engine Oil is recommended for general,
all‑temperature use. As optional choices, Mercury or Quicksilver NMMA FC‑W
SAE 25W‑40 Mineral Marine 4‑Stroke Engine Oil or SAE 25‑W40 Synthetic
Blend Marine 4‑Stroke Engine Oil may be used. If the recommended Mercury
or Quicksilver NMMA FC‑W certified oils are not available, a major outboard
manufacturer's brand of NMMA FC‑W certified 4‑Stroke outboard oil of similar
viscosity may be used.
And in the manual it has a little figure that shows 10W30 okay from 0-120F but doesn't show 25W40.

The sticker says 25w40 recommended which is what i assume is in the motor.

Don't want to be doing an oil change in 20 degree temps, but I guess I could....

[REW]

Kevin,
If you are going to be running your motor in the cold, it would make sense to change it to 10-30 full synthetic oil.

You will have no temperature issues with that oil.

Good luck

[brigeton]

For what it's worth the 115 I bought this year recommends 10-30 year around.