When travelling, it's generally smart to pack in preparation for rain or any other conditions that may arise. The rainfall in Buffalo is roughly greater than that of Lagos. You can assume this to be the case over the next 18 days.
Expect the weather to be around 27 °C on average in July. As the temperature peaks, try to get your plans done early, as flight price and availability will have an impact on your travels. The climate in Lagos is generally colder than in Buffalo.