Frost dates for San Luis Obispo
The typical last spring frost in San Luis Obispo is Jan 31, and the typical first fall frost is Dec 11. These dates come from San Luis Obispo McChesney Field, and the growing season between them is 319 days.
NCEI U.S. Climate Normals 1991-2020, annual/seasonal (c20230404), USW00093206
Early, typical and late years for San Luis Obispo
| Year type | Last spring frost | First fall frost |
|---|---|---|
| Early year (1 in 10) | Dec 23 | Nov 20 |
| Typical year | Jan 31 | Dec 11 |
| Late year (1 in 10) | Mar 7 | Jan 13 |
For spring, an early year means 1 year in 10 has a last freeze before the early date, and a late year means 1 year in 10 has a last freeze after the late date. For fall, an early year means 1 year in 10 has a first freeze by the early date, and a late year means it holds off past the late date.
The growing season in a typical year is 319 days, with the shortest at 273 days and the longest at 357 days in 1 year in 10.
Frost and freeze thresholds
| Last spring frost | First fall frost | |
|---|---|---|
| Light frost (36F) | Mar 17 | Nov 24 |
| Freeze (32F) | Jan 31 | Dec 11 |
| Hard freeze (28F) | Jan 3 | Dec 28 |
Clear, calm nights can see frost on plants at a low of 36F. A low of 32F is a freeze, and most tender plants are killed at 28F, a hard freeze.
More weather for San Luis Obispo
A typical date is the median: half of years have an earlier last spring frost, half a later one. An early year means 1 year in 10, and a late year means 1 year in 10. Dates come from the U.S. Climate Normals for 1991-2020, published by NOAA's National Centers for Environmental Information, using a daily low of 32F or below as a freeze.
The daily climate report is issued by the local National Weather Service forecast office and delivered to this page by the Iowa Environmental Mesonet of Iowa State University. Under 17 U.S.C. 105, no copyright attaches to the government-produced figures on this page, including reports, alerts, station observations, and normals, which were created by the National Weather Service and other NOAA offices. The notice that 17 U.S.C. 403 requires appears in this sentence. It does not imply endorsement by or affiliation with those agencies. See: Data sources and attribution.