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Will it freeze in Hillsborough in the next 7 nights?
No overnight lows at or below 32°F are forecast in Hillsborough during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 52°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 52°F Above 36°F · Mostly Clear
- Fri, Nov 6 51°F Above 36°F · Mostly Clear
- Sat, Nov 7 53°F Above 36°F · Mostly Clear
- Sun, Nov 8 52°F Above 36°F · Partly Cloudy
- Mon, Nov 9 52°F Above 36°F · Mostly Clear
- Tue, Nov 10 53°F Above 36°F · Partly Cloudy then Slight Chance Light Rain
- Wed, Nov 11 54°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 Hillsborough
Most years have no 28°F hard freeze at San Francisco Intl Airport, 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 | Dec 16 · Jan 8 · Feb 14 | Dec 5 · Dec 24 · Jan 24 | 353 days |
| 32°F freeze | Dec 11 · Dec 29 · Jan 13 | Dec 11 · Dec 26 · Jan 13 | 365 days |
| 28°F hard freeze | rare in most years | rare in most years | 365 days |
Average high temperature by month
1991–2020 normals at San Francisco Intl Airport
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 Hillsborough, CA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: San Francisco Intl Airport (station USW00023234, elevation 8 ft), 4.3 mi from Hillsborough. 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 Hillsborough
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Burlingame, CA | 2.5 mi | rare | rare |
| San Mateo, CA | 2.5 mi | rare | rare |
| Millbrae, CA | 3.7 mi | rare | rare |
| Belmont, CA | 4.3 mi | Jan 17 | Dec 12 |
| Foster City, CA | 6.2 mi | Jan 17 | Dec 12 |
| San Bruno, CA | 6.2 mi | rare | rare |
| San Carlos, CA | 6.2 mi | Jan 17 | Dec 12 |
| South San Francisco, CA | 6.8 mi | rare | rare |
| Pacifica, CA | 7.5 mi | rare | rare |
| Half Moon Bay, CA | 7.5 mi | Feb 6 | Dec 17 |
Frequently asked questions
When is the last frost in Hillsborough?
Hillsborough doesn’t reach 32°F in a typical year, according to NOAA’s 1991–2020 normals for the nearest station.
When is the first frost in Hillsborough?
Freezes are uncommon here; check the 7-night forecast above during cold snaps.
Can it frost in Hillsborough 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 January 8.
What growing zone is Hillsborough?
Hillsborough 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 94010. See growing zones in California.
More: all California frost dates · California growing zones · frost vs. freeze