| City | Aerate + overseed | Pre-emergent | Season |
|---|
| Los Angeles | Oct 21 – Nov 5 * | Jan 20 – Feb 10 * | Year-round |
| San Diego | Oct 21 – Nov 5 * | Jan 20 – Feb 10 * | Year-round |
| San Francisco | Oct 21 – Nov 5 * | Jan 20 – Feb 10 * | Year-round |
| Sacramento | Oct 17 – Nov 1 | Dec 22 – Jan 12 | 338 days |
| Fresno | Oct 15 – Oct 30 | Dec 24 – Jan 14 | 334 days |
* effectively frost-free — typical regional window rather than a frost-anchored one.
All California station records (330)
Every NOAA weather station in California 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 California
Across the 332 California locations with complete 1991–2020 frost
normals, the average last spring frost — the anchor for pre-emergent and spring
work — ranges from Jan 1 (Bodega 6 WSW) to Dec 31
(Burbank Glendale Pasadena Airport), a spread of about 52 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 California lawn year in one paragraph
California lawns run on two opposite calendars. Tall fescue and bluegrass lawns treat early fall as the main event — aerate, overseed, feed — with spring for pre-emergent and light feeding. Bermuda and Zoysia lawns flip it: establish and feed from late spring through summer, stop nitrogen 6–8 weeks before frost, and accept winter brown as normal. Identify your grass first; every date on this page depends on it. Details by task: when to overseed in California, when to aerate in California, when to apply crabgrass pre-emergent in California, and more above.