The Hebrew words for "almond tree" (shaqed) and "watching" (shoqed) sound very similar. God used this connection to teach Jeremiah something important. The almond tree blooms very early, before other trees, in January or February.
When God showed Jeremiah an almond tree, he was telling him that just as the almond tree is alert and ready to bloom early, God is always alert and watching over his people. We can see this same idea of God's constant watchful care in Psalm 121:3–8.