When to plant white maize in Limpopo

We've been planting WE5323 in mid-January for 20 years now. The key is to wait for at least 50mm of rain before you put seed in the ground. Too early and you waste seed, too late and the frost catches you in May. I check the 10-day forecast on the app and only plant once I see a solid rain window. Last season we got 7.2 tonnes per hectare — our best yet.