Unusual Rain
Scholars have said that seeing the sky rain swords may indicate people being afflicted with arguments and disputes, while watermelon rain might suggest illness. Rain falling without clouds is considered unexpected relief and provision. Interpreters mention that terms like "ghayth" (beneficial rain) and "descending water" are better for interpretation than the word "matar" (rain) itself in certain contexts.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam