ROOTED IN REAL DATA Historical data. Thoughtful planning. No weather guarantees.
California · NOAA station reference

Hearst Castle
frost dates.

A source-backed view of historical freeze risk at this weather station. Use it to understand the season, not as a promise about your garden or this year’s weather.

Infrequent freezing; conditional dates
Freezing is uncommon in the normal model. The dates describe cold seasons in which freezing occurred, not all years. Do not use them as an automatic planting season.
Modeled annual freeze occurrence: 40%. Date percentiles below are conditional on a cold season containing a 32°F freeze, not all years.
Last spring 32°F freeze · conditional medianFeb 13
First fall 32°F freeze · conditional medianFeb 1 (next year)
Days between conditional medians353 days
Uncertainty, made visible

One date never tells
the whole season.

1991–2020 station normals
32°F minimum-temperature threshold

Last spring freeze

Among cold seasons with a freeze: probability of the last occurrence on this date or later.

10%Mar 31
30%Feb 27
50%Feb 13Median reference
70%Jan 19
90%Dec 29Prior year

The 10% date is later in spring than the median: a more cautious historical reference, still not a guarantee.

First fall freeze

Among cold seasons with a freeze: probability of the first occurrence on this date or earlier.

10%Dec 16
30%Jan 8Next year
50%Feb 1Next yearMedian reference
70%Feb 21Next year
90%Mar 20Next year

The 10% date is earlier in fall than the median: a more cautious harvest-planning reference.

These percentages are conditional on a cold season containing a 32°F freeze; they are not probabilities across all years. They describe historical climate, not this season’s forecast. The spring and fall probability directions are intentionally different. A garden can be warmer or colder than the reference station.

Know the evidence

The reference
behind the numbers.

Official station name
HEARST CASTLE, CA US
NOAA station ID
USC00043882
Coordinates
35.6842, -121.1683
Station elevation
465.1 m / 1526 ft
Normal period
1991–2020
Source retrieved
2026-10-02
Source modified
Tue, 27 Jun 2023 15:16:19 GMT
Original NOAA station record
Put the data in context

A baseline.
Not a forecast.

Weather stations measure a particular location. Differences in elevation, exposure, nearby water, terrain and urban heat can change conditions in an individual garden.

  • 32°F is the station air-temperature threshold; visible frost on leaves can differ.
  • Median dates still leave substantial historical freeze risk.
  • Historical normals summarize 1991–2020, not current weather.
  • Crop suitability requires regional horticultural guidance, soil warmth, cultivar and day length.
Understand the method Check the current NWS forecast
Traceable, down to the field

How strong is this reference?

Source variableHistorical dateYearsNOAA completeness
Last spring freeze · 10%Mar 3120R · Representative
Last spring freeze · 30%Feb 2720R · Representative
Last spring freeze · 50%Feb 1320R · Representative
First fall freeze · 10%Dec 1620R · Representative
First fall freeze · 30%Jan 8 (next year)20R · Representative
First fall freeze · 50%Feb 1 (next year)20R · Representative

Our ordinary calendar model requires supported dates and standard/representative source quality with at least 10 years. This does not erase local uncertainty.

Explore the geographic connection

Places using this nearby reference

Connections are based on Census internal points and straight-line distance.

A wider view

Other California references

Explore the state