On the Samsung Galaxy S5, the weather widget Accu Weather is installed from stock with which you can always check on your home screen the current weather forecast for a previously defined location. If this weather widget on your Samsung Galaxy S5 suddenly is longer visible on the home screen, then you have probably deleted it by mistake. But this is not a problem because you can add the weather widget very easily as follows to your home screen again.
When you are on the home screen press and hold the left soft key button on your Samsung Galaxy S5. This will now minimize the home screen and then display various menu buttons to you. Tap the button "widgets". Now scroll through the widget pages until the "Weather" widget is displayed. This widget you can now place by long pressing your finger on it until this hovers and can be placed on the home screen.
You will then have placed as usual the weather widget “Accu Weather” on your Samsung Galaxy S5 home screen.