Announced by Abdullah Almuntassir on the X-Plane.org Forums, Ultra Weather XP (UWXP) version 2.6.2 will be releasing on December 25th (Christmas day). 

An extensive feature list was provided by the developers, highlighting a plethora of new features coming to the addon with this update.

Some exciting additions from the feature list include the addition of a dynamic night sky which reflects city lights to light up the night sky, “New Dynamic Clouds Coloring System that controls the coloring and brightness of clouds,” and a “New Dynamic Sky Coloring System that controls the density of sky color during the time.”

You can view the full feature list below. 

• The Plugin Dynamic functions have been completely rewritten.
• The Dynamic functions have 3 selectors now to controls the results of these functions.
• New enhanced sky colors including illuminated fog by direct sunlight with adding a new checkmark selector to select between illuminated and unilluminated fog.
• New Dynamic Atmosphere System that controls the scale of the horizon during the time, weather situation, and camera viewpoint.
• New Dynamic Sky Coloring System that controls the density of sky color during the time, weather situation, and camera viewpoint, with adding three selectors to allow the user to select the density he likes.
• New Dynamic Night Sky that reflects cites lights to illuminate the sky during night time, camera viewpoint, and weather situation.
• New Dynamic Sun Glow System that controls the sun glow intensity during the time, camera viewpoint, and weather situation, with adding three selectors to allow the user to select the strength he likes.
• New Dynamic Sun Lighting system that controls the strength of sun lighting objects and water, during the time, weather situation and camera viewpoint, with adding three selectors to allow the user to select the strength he likes.
• New Dynamic Visibility System that controls the density of fog during the time, camera viewpoint, and weather situation, with adding three selectors to allow the user to select the density he likes.
• New Dynamic Visibility Raleigh that controls the coloring of sun direct lights that control the blue haze during the time, camera viewpoint, and weather situation.
• New Dynamic Raleigh Scattering system that controls the blueness of the haze that affected by sun direct light during the time, camera viewpoint, and weather situation, with adding three selectors to allow the user to select the density he likes.
• New Dynamic Mie Scattering System that controls the density of greyish haze realistically during the time, camera viewpoint, and weather situation, with adding three selectors to allow the user to select the density he likes.
• Clouds Textures coloring enhanced.
• New Dynamic Clouds Coloring System that controls the coloring and brightness of clouds and sun direct light over clouds during the time, camera viewpoint, and weather situation, with adding three selectors to allow the user to select the color density he likes and three selectors to allow the user to select the brightness intensity he likes.
• New Dynamic Night clouds reflect cites lights illuminate to the clouds during night time, camera viewpoint, and weather situation.
• Improved Simulate Volumetric Clouds that changed the clouds size, opacity, and fading to give the feeling of volumetric clouds, continuously during the time, camera viewpoint and weather situation with adding three selectors to allow the user to select the clouds sizing he likes and three selectors to allow the user to select the fading intensity he likes.
• New checkmark called "Smoothen Far Clouds" to use it with "Increased Clouds Distance" that will blend the clouds with the sky while using Increase Clouds Distance to give better clouds looking in the distance.
• Improved "High Altitude Clouds" that limit any high altitude clouds above FL240 to be only Cirrus clouds only. without affecting the reported weather like in 2.6.1
• New HD Shadows that will fix the jagged shadows.
• Improved Dynamic Shadow that controls the density of the shadow during the time, camera viewpoint, and weather situation.
• New Slider to control the total distance in meters that shadows can be drawn in farther from the camera view.
• New Dynamic Water System that controls the sizing and the shape of the waves during the time, weather situation, camera viewpoint, and wind speed with adding three selectors to allow the user to select the size he likes. 
• New Dynamic Light Haze system that controls the sizing, strength, and hazing of the lights during nighttime, and the weather situation. with adding three selectors to allow the user to select the strength he likes.
• New Dynamic Ambient Sounds that will run sounds of cities and birds during the day time, and during the night time, it will run the sounds of crickets and winds. If your aircraft position over the city, you will hear the sound of cities and birds or crickets depending on the number of city objects. Meanwhile, the sound of wind depends on the speed of the wind and the city objects. If the city is large and there are too many objects, then the city sound will increase and the wind will decrease. The opposite thing will happen if the city is too small or the objects are too low. Also, the sound of cities will decrease and the wind will increase if the camera viewpoint is moving up to a very high altitude just like in real life.

A lengthy new promotional video was also provided by the developers, which can be found on their YouTube channel. The video goes through the many new features found in the product and showcases the clouds, sky, and much more.

You can view the video below.

The developers have also provided a list of known bugs from the previous version of UWXP that have now been fixed with this newest update. You can view this list below.

• Fix the remaining issue with reported weather that not presented correctly as reported in METAR. (Fixed)
• Enhance the "Dynamic Clouds Coloring" (Done)
• Enhance the "Dynamic Sky Coloring" (Done)
• Fix "Clouds Terrain Blend" (Removed from UI, "Simulate Volumetric Clouds" will handle it by another method) 
• Enhance the Cirrus Clouds textures. (Done)
• Enhance the "Dynamic Water Waves" (Done)
• Enhance the "Dynamic Light Haze" (Done)
• Enhance the "Dynamic Mie Scattering" (Done)
• Enhance the "Dynamic Raleigh Scattering" (Done)
• Enhance the "Simulate Volumetric Clouds" (Done)
• Fix the hard edge of clouds in low visibility while using "Increase Cloud Distance" (Done)
• Fix the remaining clouds popping in and out. (This can't be fixed) UNLESS YOU DISABLED (Increase Cloud Distance)
• Enhance Flying through clouds effect. (Sort of, as it works depending on Clouds Fading Option the lowest selection the better effect)
• Adjust the whole cloud sizes to gain more FPS. (Done)
• Enhance the shadows. (Done)
• can't write @ while activating. (it should write it now)
• can't use external lights textures even if "Use UWXP Lights" is unchecked (Fixed)
• Blurry lights textures (Replaced by Enhanced textures)

It was also confirmed that v2.6.2 of UWXP will be free for all existing users of version 2.6.X, although users of v2.5.1, 2.4, or older will be subject to an upgrade fee of $9.95, which is $25.05 off the original price of the product.

Ultra Weather XP v2.6 is available for purchase from the X-Plane.org Store for $35, although if you wish to receive your upgrade price, you must purchase the product from the developers store and follow the correct steps to receive the discount.

You can view the original announcement post on the X-Plane.org Forums.