In terms of precipitation, rainfall in Gisborne ranges from 2.0 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. November is typically the driest time to visit Gisborne when rainfall is around 2.0 in.
If weather is an important factor for your trip to Gisborne, use this chart to help with planning. For those seeking warmer temperatures, January is the ideal time of year to visit, when temperatures reach an average of 66.2 F. Travelers looking to avoid the cold should look outside of June, when temperatures are typically at their lowest (around 50.0 F).
Peak season on the North Island of New Zealand runs from around December through to March, and accommodations will accordingly be more expensive during this time. However, the weather will also be warm and all attractions will be open, making it a great time to visit anyway. Try April or November for good weather and cheaper deals on hotels, while even July and August can be fine for outdoor activities.
Gisborne has an excellent local bus system which is known to be reliable and extensive. Get hold of a map when you arrive at the airport. There are also some cycling trails to follow. However, for total mobility and access to Auckland and attractions like Morere, a rental car is essential.