It only rains at spawn

This isn’t a bug, it just doesn’t rain in Savanna biomes.

Hi!
Thank you for your report! 

However, this issue is Working as Intended. 
Some biomes do not have precipitation, Savanna biome is one of them.

Please note, that mechanics of the game may change between updates. 
Things such as graphics, sounds, world creation, biomes, redstone, villagers, and animals may not work the same in current versions. 

Full Version History – Feature Requests and Suggestions 

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