Condition icon packs support add activity with action "org.omnirom.WeatherIconPack" the name is used to defined the prefix for the image names default should be .weather.
<activity
android:name=".weather_vclouds"
android:label="LockClock (vclouds)" >
<intent-filter>
<action android:name="org.omnirom.WeatherIconPack" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>