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Will it freeze in Half Moon Bay in the next 7 nights?
No overnight lows at or below 32°F are forecast in Half Moon Bay during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 48°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST.
No nights at or below 36°F in the National Weather Service forecast for the next 7 nights.
- Tonight 48°F Above 36°F · Partly Cloudy then Patchy Fog
- Fri, Nov 6 47°F Above 36°F · Partly Cloudy
- Sat, Nov 7 50°F Above 36°F · Partly Cloudy
- Sun, Nov 8 52°F Above 36°F · Mostly Cloudy then Patchy Fog
- Mon, Nov 9 52°F Above 36°F · Partly Cloudy
- Tue, Nov 10 52°F Above 36°F · Patchy Fog then Slight Chance Light Rain
- Wed, Nov 11 52°F Above 36°F · Chance Light Rain
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Half Moon Bay
Most years have no 28°F hard freeze at Half Moon Bay, according to NOAA’s 1991–2020 Climate Normals. Check the short-term forecast above during cold snaps.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Feb 23 · Apr 3 · May 1 | Oct 20 · Nov 20 · Dec 16 | 230 days |
| 32°F freeze | Dec 17 · Feb 6 · Mar 25 | Nov 25 · Dec 17 · Feb 13 | 328 days |
| 28°F hard freeze | Dec 5 · Jan 5 · Feb 26 | Dec 4 · Dec 31 · Feb 23 | 365 days |
Average high temperature by month
1991–2020 normals at Half Moon Bay
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Half Moon Bay, CA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Half Moon Bay (station USC00043714, elevation 27 ft), 0.4 mi from Half Moon Bay. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Half Moon Bay
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Hillsborough, CA | 7.5 mi | rare | rare |
| Belmont, CA | 8.7 mi | Jan 17 | Dec 12 |
| Millbrae, CA | 9.3 mi | rare | rare |
| Burlingame, CA | 9.3 mi | rare | rare |
| San Mateo, CA | 9.3 mi | rare | rare |
| San Carlos, CA | 9.9 mi | Jan 17 | Dec 12 |
| Pacifica, CA | 9.9 mi | rare | rare |
| Woodside, CA | 11 mi | Feb 25 | Nov 25 |
| San Bruno, CA | 11 mi | rare | rare |
| Foster City, CA | 12 mi | Jan 17 | Dec 12 |
Frequently asked questions
When is the last frost in Half Moon Bay?
On average, the last spring frost (32°F) in Half Moon Bay is around February 6. In about 1 year in 10 it comes after March 25, and in 9 years in 10 it comes after December 17.
When is the first frost in Half Moon Bay?
The first fall frost (32°F) usually arrives around December 17. There’s a 10% chance of a freeze by November 25 and a 90% chance by February 13.
Can it frost in Half Moon Bay after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after April 3.
What growing zone is Half Moon Bay?
Half Moon Bay is in USDA Plant Hardiness Zone 10a (average annual extreme minimum temperature 30 to 35°F), based on the 2023 USDA map for ZIP code 94019. See growing zones in California.
More: all California frost dates · California growing zones · frost vs. freeze