"improved weather" is correct and usable in written English.
You can use it to describe when the weather gets better after a period of bad weather. Example sentence: After several days of rain, the forecast for the weekend showed improved weather.
Improved weather conditions on Friday enabled medics to travel to the hotel by helicopter.
Improved weather allowed firefighters to corral most fires into smaller, more controllable blazes, said a fire department spokesman, Nikos Diamandis.
Improved weather conditions today stabilized the fire that has destroyed huge swathes of forest and residences here and threatened a major nuclear weapons laboratory.
The field has thus far apparently yielded only modestly improved weather prediction, and had little, if any, impact on challenges such as getting computers to program themselves.
The most dangerous countries to work in were Somalia and Afghanistan.Somali pirates took advantage of improved weather conditions at sea and stepped up their attacks on foreign ships.
Additional reductions will be possible in moving to 15 minute scheduling, as well as with greater balancing area coordination and improved weather forecasting.
That car's body color is molded into the plastic, although a clear-coat finish is added for gloss and improved weathering ability.
Fleets of robotic aircraft could improve weather forecasts.
Gawande passingly notes that checklists could be used to improve weather prediction.
Some amendments are quick strikes, like eliminating $111 million for improving weather satellite technology.
Chahine, M. T. et al. AIRS: improving weather forecasting and providing new data on greenhouse gases.
