Keep in mind that the humidity is going to rise as the temperature falls, all else being the same. Mine almost always gets up in the 90% range, the last two days it was 100%. Watch your dewpoint and humidity as the temperature begins to fall.
And yes, the closer to the ground, generally the more moist, especially in the early morning hours. This morning I had a low fog over my backyard... really nice to look at.
And remember, temp and humidity should be measured at 5 feet.