Why does my d4 light blink on my Honda Accord when raining?

The blinking D4 light in your Honda Accord during rain could indicate a transmission issue or a malfunction in the vehicle's electronic systems. Moisture may be affecting sensors or electrical connections related to the transmission. It's advisable to check for any water ingress or to have the vehicle inspected by a mechanic to diagnose the specific cause and ensure proper functioning. Regular maintenance can help prevent such issues.