According to the USDA Honolulu is in USDA Zone 12a. Here is some general info for USDA Zone 12a to help you get started.
Average Date of Last Frost (spring) | Never |
Average Date of First Frost (fall) | Never |
Lowest Expected Low | 50°F |
Highest Expected Low | 55°F |
This means that on a really cold year, the coldest it will get is 50°F. On most years you should be prepared to experience lows near 55°F.
You can view the USDA Zone map for Hawaii here:
Below is a list of planting guides for Honolulu, HI. These guides are based on data from Zone 12a.
Vegetables
Herbs
Flowers