| City | Seed / establish | Pre-emergent | Season |
|---|
| Honolulu | Feb 24 – Mar 10 * | Jan 20 – Feb 10 * | Year-round |
| Hilo | Feb 24 – Mar 10 * | Jan 20 – Feb 10 * | Year-round |
* effectively frost-free — typical regional window rather than a frost-anchored one.
All Hawaii station records (2)
Every NOAA weather station in Hawaii with complete 1991–2020 frost normals — pick
the one nearest you (similar elevation matters more than plain distance).
Not sure which station to trust? Use the
ZIP code lookup
for the quick answer, or pick the station whose terrain most resembles your yard.
Lawn timing geography of Hawaii
Across the 2 Hawaii locations with complete 1991–2020 frost
normals, the average last spring frost — the anchor for pre-emergent and spring
work — ranges from Jan 26 (Kanalohuluhulu 1075) to Apr 12
(Mauna Loa 5 NNE), a spread of about 11 weeks driven by elevation, latitude, and terrain.
The same job can be weeks apart at opposite ends of the state, which is why a
state-level date is only a starting point — pick the location nearest your yard and
plan from its calendar.
The Hawaii lawn year in one paragraph
The Hawaii lawn year lives in the warm months: pre-emergent in late winter before soil crosses 55°F, establishment and the first feeding after full green-up, aeration in the heat of active growth, and steady mowing all summer. The discipline that separates good southern lawns is the stop date — no nitrogen within 6–8 weeks of first frost, so the lawn hardens off and goes dormant on schedule. Details by task: when to overseed in Hawaii, when to aerate in Hawaii, when to apply crabgrass pre-emergent in Hawaii, and more above.