Why is air from the gulf of mexico so much more humid than air from the pacific ocean at the same latitude?

The air from the 'Gulf of Mexico' is much more 'humid' than air from the 'Pacific Ocean' at the same latitude because the air flowing over the 'Gulf of Mexico' bears more 'water vapor' that the air flowing over the 'Pacific Ocean'.

Explanation:

The vapor bearing capacity of the air from the 'Gulf of Mexico' is enhanced than that of the 'Pacific Ocean' due to the presence of land around the Gulf. The air from the Pacific has a 'low dew-temperature point'. Moreover, the water of the 'Pacific Ocean' is cooler compared to the 'Gulf of Mexico' and thus produces less water vapor.