The player should be able to quickly establish what the weather is via a quick glance at the indicator.
Clarity should always be a priority when choosing appropriate icons. For example: a snowflake is a better choice than an icon showing a cloud and snow, as that could easily be mistaken for rain.
Colour is particularly useful when depicting temperature: blue feels cold, red feels hot.
When showing current and future weather in chronological order, displaying it next to the current time is a good way of helping the player understand what the information is depicting. As time increases, the weather timeline moves. This not only informs the player of what weather is coming next, but also allows them to estimate how long the current weather will last.