UAE humidity persists as October brings cooler nights.
Abu Dhabi: The high humidity experienced across parts of the UAE on Tuesday morning is part of a familiar seasonal pattern, as overnight temperatures begin to ease while moisture levels remain high. The combination can lead to muggy conditions and increase the likelihood of fog.
According to the National Centre of Meteorology (NCM), moisture moving inland from the Arabian Gulf, combined with clear skies, light winds and lower overnight temperatures, creates favourable conditions for high humidity. As air near the surface cools and approaches saturation, the chances of fog forming also increase.
Such conditions are typical as the UAE transitions from summer into autumn and gradually towards winter. The NCM expects humidity levels to remain elevated through October, meaning cooler temperatures may not immediately bring relief from damp and sticky mornings.
The centre explained that north-westerly winds can carry moisture from the Arabian Gulf towards coastal and inland areas during the evening and overnight. When winds become lighter, this moisture can remain trapped close to the surface.
At the same time, clear skies allow the ground to lose heat overnight, cooling the air immediately above it. As temperatures approach the dew point — the level at which water vapour begins to condense — relative humidity increases, creating favourable conditions for mist or fog.
Humidity can rise even when no additional moisture enters the air. Relative humidity measures how close the air is to becoming saturated at a given temperature, which means a cooler morning can record higher humidity levels than a warmer afternoon even when the amount of moisture in the air remains largely unchanged.
Once the air reaches saturation, water vapour begins to condense into tiny droplets suspended near the surface, resulting in fog. According to the National Centre of Meteorology (NCM), key conditions for fog formation include relative humidity nearing 90 to 100 per cent, sufficient atmospheric moisture, light or calm winds and falling surface temperatures.
High humidity can also make warm conditions feel more uncomfortable. When the air contains a large amount of moisture, sweat evaporates more slowly from the skin, making it harder for the body to cool itself effectively.
Conditions higher in the atmosphere can further prolong the build-up of moisture near the ground. High pressure in the upper atmosphere can suppress rising air, while overnight cooling may create a temperature inversion, where a layer of cooler air becomes trapped beneath warmer air above.
This can keep moisture concentrated close to the surface, creating favourable conditions for persistent humidity, mist and fog during the early morning hours.
This atmospheric set-up limits vertical mixing and helps trap moisture close to the ground, creating favourable conditions for radiation fog, one of the most common types of fog in the UAE.
Wind speed also plays an important role. While north-westerly winds can carry moisture inland, stronger winds may disrupt fog formation by mixing the lower layers of the atmosphere. The overall impact depends on the strength of the winds and how much moisture they carry.
When will the humidity ease?
For residents wondering when conditions will improve, there are two different timescales to consider.
During the day, rising temperatures after sunrise can reduce relative humidity and help clear fog or mist. Stronger winds can also disperse the shallow layer of moist air near the surface. However, this does not necessarily mean the moisture has disappeared, and humid conditions can return overnight as temperatures fall.
Looking ahead, the NCM’s October outlook suggests humidity will remain relatively high throughout the month. The average maximum relative humidity for October is around 78 per cent, although this is a climatic average and does not represent a limit on individual readings or a forecast for every part of the country.
The immediate forecast also indicates humid conditions on Tuesday night and Wednesday morning across some coastal and inland areas, with a possibility of fog or mist.
More noticeable relief from the sticky conditions will largely come as temperatures continue to fall. Although humidity is expected to remain elevated through October, cooler weather should gradually make conditions feel less uncomfortable.
High relative humidity can still occur during winter nights and mornings, when it may lead to fog without creating the same oppressive feeling associated with high summer temperatures.
The NCM noted that fog is more frequent in December, January and February, meaning the end of the UAE’s hotter weather does not necessarily signal the end of humid conditions.
October’s weather outlook also points to temperatures above the monthly average, along with slightly higher-than-average rainfall.
The transition towards cooler weather is expected to be gradual, with the UAE continuing to experience warm daytime temperatures, humid nights and occasional fog as seasonal conditions slowly change.
