Frost Dates for Portola Valley, CA
Based on data from Woodside Fire Stn 1 weather station, 3 miles away
Elevation: 459 ft
Frost Dates
Last Spring Frost (50%) A 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide.
February 25
First Fall Frost (50%) A 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date.
November 25
30% Probability
Only a 30% chance of frost remaining by this date. Use these dates for a safer planting window, especially for tender plants sensitive to cold.
Last Spring Frost
March 13
First Fall Frost
November 17
Hard Freeze (28°F)
Last Spring Hard Freeze
January 13
First Fall Hard Freeze
December 12
Growing Season
274 Days
February 25 to November 25
USDA Hardiness Zone
Hardiness zones indicate which perennial plants can survive winter in your area. For annual vegetables, frost dates and growing season length matter more than hardiness zone.Zone 9a
Avg. annual minimum: 20 to 25°F
Köppen Climate
The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
Csb
Warm-Summer Mediterranean
Warm, dry summers and mild, wet winters. Similar to hot-summer Mediterranean but cooler. Great for a wide range of vegetables and fruit trees with moderate water needs.
Temperature
30°
50°
70°
90°
Avg High
Avg Temp
Avg Low
Light Frost (32°F)
Temperature table
| Month | Avg High | Avg Temp | Avg Low |
|---|---|---|---|
| January | 61° | 50° | 38° |
| February | 64° | 52° | 40° |
| March | 69° | 55° | 41° |
| April | 73° | 58° | 43° |
| May | 78° | 63° | 47° |
| June | 84° | 67° | 50° |
| July | 88° | 71° | 53° |
| August | 89° | 71° | 53° |
| September | 87° | 69° | 51° |
| October | 80° | 63° | 46° |
| November | 68° | 54° | 41° |
| December | 61° | 49° | 37° |
Precipitation
0"
2"
4"
6"
6.7"
Precipitation table
| Month | Precipitation |
|---|---|
| January | 6.7 |
| February | 6.5 |
| March | 5.9 |
| April | 3.9 |
| May | 0.8 |
| June | 0.0 |
| July | 0.0 |
| August | 0.0 |
| September | 0.0 |
| October | 1.2 |
| November | 4.8 |
| December | 6.5 |
Sunrise / Sunset
Daylight
Pacific Time (PT)
Longest: 14h 35m · Shortest: 9h 25m
Sunrise and sunset table
| Month | Sunrise | Sunset | Daylight |
|---|---|---|---|
| January | 7:28 AM | 5:09 PM | 9h 41m |
| February | 7:05 AM | 5:42 PM | 10h 37m |
| March | 7:27 AM | 7:10 PM | 11h 43m |
| April | 6:40 AM | 7:38 PM | 12h 58m |
| May | 6:05 AM | 8:06 PM | 14h 01m |
| June | 5:52 AM | 8:26 PM | 14h 34m |
| July | 6:04 AM | 8:25 PM | 14h 21m |
| August | 6:30 AM | 7:56 PM | 13h 27m |
| September | 6:57 AM | 7:10 PM | 12h 14m |
| October | 7:24 AM | 6:24 PM | 11h 01m |
| November | 6:56 AM | 4:53 PM | 9h 57m |
| December | 7:22 AM | 4:48 PM | 9h 26m |
Nearby Stations
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