Ideally, when you are performing the saturated DO calibration point with the sensor in the bottle above a small amount of water, the air in the bottle and the water should be the same temperature. This is the temperature you would look up on the chart.

If they are not the same temperature, use a very small amount of water in the bottle, and by the time the DO probe has “warmed up,” they will be. It you can’t wait for them to equilibrate, the air temperature is actually the better one to use for the chart. This is because the temperature compensation thermister and the DO membrane itself are at the air temperature. Yes, the water will have a slightly different vapor pressure if it is a different temperature, but this is pretty negligible when the other factors are taken into consideration.