Under Account > Integrated Tools there is a collection of account upgrades available for both Free and Pro accounts. Any enabled tools will have a checkmark.
The Weather Integration, provided by DarkSky.net, shows weather information about your delivery location starting a few days prior to the delivery date.
Once enabled, the forecast will show 3-5 days of weather for the delivery location on the Orders page. If there is no address set for the customer, no weather information will be displayed.