The canal works with gravity, utilizing water from seas at a higher elevation. The seas are low on water because the rivers that flow into them were carrying a lot less water than usual during summer. It's winter now, the rivers have normalized somewhat, but the overall water content of the system is still quite low as it can't exactly replenish when it's drained at about the same rate it is filling up with. That's why throughput of the canals is still lower than what the demand for it would require.

On top of that, temperatures in Southern America are still insane. It's winter and there are many places at 110F+.