Castle Rock State Park Weather
Park • San Francisco Bay Area
Castle Rock State Park sits on one of the highest ridges in the Santa Cruz Mountains, along Highway 35 (Skyline Boulevard). It lies about 2½ miles southeast of the highway's junction with Highway 9 at Saratoga Gap. California State Parks manages it for its wind-sculpted sandstone, including the namesake Castle Rock that draws climbers. About 34 miles of trail connect to the Skyline to the Sea Trail and Big Basin. The canyons below hold redwood shade, but much of this park is open ridge with black oaks, knobcone pines and wide views.
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10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Castle Rock State Park weather today and through the year
It's 45°F at Castle Rock State Park right now (feels like 38°F), with 10 mph wind and a comfort score of 54. Today's forecast high at Castle Rock State Park is 51°F, 10°F below the mid November normal of 61°F. Fog is forecast to linger into the afternoon today at Castle Rock State Park. In November, fog here usually thins by 3 PM. The best window today is 2 PM to 5 PM, at about 43°F with a 5 mph wind (comfort 42).
August is the warmest month at Castle Rock State Park, with an average high of 81°F. December is the coldest, with an average low of 39°F. January is the wettest month (9.1 in.), out of about 45.0 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Castle Rock State Park are July, September, and August. The best hours are usually 9 AM to noon in July, 3 PM to 6 PM in September, and 9 AM to noon in August.
At close to 3,000 feet on the crest of the Santa Cruz Mountains, Castle Rock usually sits above the summer marine layer. That layer is the sheet of cool, damp ocean air that brings fog. On a typical fog day you look down on a gray sea filling the San Lorenzo Valley and the coast toward Santa Cruz. The ridge itself is sunny and dry.
Forecast updated November 15, 2026 at 4:00 AM PST. Climate figures come from NOAA 1991-2020 normals. Hourly patterns come from NOAA's HRRR hourly analysis from September 2014 to April 2026.
What to expect at Castle Rock State Park in the next few days
No active National Weather Service alerts for this location.
Fog
Fog is forecast to linger into the afternoon today at Castle Rock State Park. In November, fog here usually thins by 3 PM.
Best time to go
The best window today is 2 PM to 5 PM, at about 43°F with a 5 mph wind (comfort 42).
Climbing conditions
Best climbing day this week: Friday, with 2 daylight hours that are dry, 45 to 80°F, and under 18 mph wind. 0 of the next 7 days have at least 4 such hours.
Best day this week
Of the next 7 days, Friday looks best for Castle Rock State Park, with a 49°F high and midday comfort near 56. Thursday looks weakest (37).
Better weather nearby
It's 45°F with a comfort score of 54 at Castle Rock State Park right now. Pescadero Creek County Park, 13 miles away, is 56°F with a comfort score of 80. See that forecast
Rain
Next good chance of rain: today (87%, about 0.47 in.).
Live weather map
Weather around Castle Rock State Park right now
Overcast and 45° at Castle Rock State Park right now. Pescadero Creek County Park, 13 mi away, is 56° and more comfortable.
About the live weather map for Castle Rock State Park
The map centers on Castle Rock State Park and stacks fog, satellite clouds, and precipitation radar on one view. Clouds come from the GOES-West satellite and rain from NOAA radar, and both show current conditions. Fog comes from our HRRR-based fog model, and the slider steps through its forecast for the next 12 hours.
Dots mark nearby places with their current temperature, colored by comfort score. Use the layer buttons to turn any layer off, or open the full map for every destination in the region.
Nearby Temperature Comparison
Conditions at nearby San Francisco Bay Area destinations
Tip: Bay Area temperatures can change by 20 to 30°F over a short distance because of microclimates.
Castle Rock State Park vs nearby places
Typical summer conditions compared with Castle Rock State Park, from the same NOAA HRRR hourly record. The list shows the closest places, then nearby places whose climate differs the most.
| Place | Distance | Summer afternoons | Morning fog | Afternoon wind | Compared with Castle Rock State Park |
|---|---|---|---|---|---|
| Sanborn County Park | 0.8 mi | same | 12% | 6 mph | same 3 km weather-model cell, so our hourly data cannot tell them apart |
| Saratoga | 4.5 mi | +8°F | 10% | 8 mph | 2,605 ft lower and about 8°F warmer on summer afternoons |
| Rancho San Antonio | 7 mi | +5°F | 16% | 9 mph | 2,589 ft lower and about 47% less rain a year |
| Año Nuevo State Park | 15.5 mi | -18°F | 42% | 14 mph | about 18°F cooler on summer afternoons and more summer morning fog (42% vs 12% of morning hours) |
| Purisima Creek Redwoods | 19.4 mi | -12°F | 57% | 7 mph | more summer morning fog (57% vs 12% of morning hours) and about 12°F cooler on summer afternoons |
| Half Moon Bay | 24.5 mi | -13°F | 64% | 8 mph | more summer morning fog (64% vs 12% of morning hours) and about 13°F cooler on summer afternoons |
Places with a climate like Castle Rock State Park's
- Henry W. Coe State Park (32 mi away): similar temperatures through the year
- Fairfax (59 mi away): similar temperatures through the year
- Robert Louis Stevenson State Park (102 mi away): similar temperatures through the year
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Castle Rock State Park climate comparisons mean
These cards compare recent conditions at Castle Rock State Park with the available local baseline. Temperature and year-to-date rainfall use long-term normals when available. Fog, sunshine, wind, and comfort use the matching recent or modeled baseline identified on each card.
Positive and negative differences describe how Castle Rock State Park departs from its own usual pattern. They should not be read as a direct comparison with another city or as a forecast beyond the period shown.
Castle Rock State Park weather by month
August is the warmest month at Castle Rock State Park, with an average high of 81°F. December is the coldest, with an average low of 39°F. January is the wettest month (9.1 in.), out of about 45.0 in. a year. Morning fog peaks in May, when fog or low cloud covers 28% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 10% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Castle Rock State Park are July, September, and August. The best hours are usually 9 AM to noon in July, 3 PM to 6 PM in September, and 9 AM to noon in August.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 56°F | 40°F | 9.1 in | 13 | 22% | 31% | 9 mph | 9.9 h | 20 |
| Feb | 55°F | 39°F | 8.8 in | 12 | 20% | 28% | 10 mph | 10.8 h | 9 |
| Mar | 59°F | 39°F | 6.6 in | 11 | 22% | 33% | 9 mph | 11.9 h | 21 |
| Apr | 61°F | 40°F | 3.1 in | 7 | 25% | 27% | 8 mph | 13.1 h | 57 |
| May | 67°F | 45°F | 1.3 in | 5 | 28% | 24% | 8 mph | 14.2 h | 72 |
| Jun | 74°F | 49°F | 0.3 in | 2 | 13% | 13% | 6 mph | 14.7 h | 89 |
| Jul | 80°F | 54°F | 0.0 in | 1 | 10% | 10% | 5 mph | 14.5 h | 94 |
| Aug | 81°F | 54°F | 0.0 in | 1 | 13% | 11% | 5 mph | 13.5 h | 93 |
| Sep | 79°F | 53°F | 0.1 in | 2 | 14% | 14% | 6 mph | 12.3 h | 94 |
| Oct | 72°F | 49°F | 1.9 in | 6 | 11% | 14% | 7 mph | 11.1 h | 81 |
| Nov | 61°F | 42°F | 4.5 in | 9 | 15% | 21% | 8 mph | 10.1 h | 59 |
| Dec | 55°F | 39°F | 9.1 in | 12 | 26% | 31% | 9 mph | 9.6 h | 13 |
Morning fog is the share of hours from 6 to 10 AM with fog or low cloud. Midday cloud is the average from 11 AM to 3 PM, and afternoon wind is the average from 1 to 5 PM. The highlighted rows are the most comfortable months.
In summer, recent daily NOAA readings at Castle Rock State Park average about 4°F cooler than the 1991-2020 normals. The normals average over a wider area that also covers nearby terrain. Read the monthly highs as a rough range, and use the recent months below for what Castle Rock State Park has actually seen.
What makes Castle Rock State Park's weather different
Among the 58 San Francisco Bay Area parks we track, Castle Rock State Park has the calmest summer afternoons.
- #1of 58
calmest summer afternoonsamong San Francisco Bay Area parks
When the fog burns off
2 PMwhen May fog usually thins (29% foggy at 9 AM)
Fog or low cloud covers Castle Rock State Park in 29% of 9 AM hours in May, the foggiest month. It usually thins to a third of that by 2 PM. July mornings are the least foggy (10%).
Wind
8 mphtypical afternoon wind, with no strong daily build-up
Castle Rock State Park has no strong afternoon wind build-up. Afternoons average about 8 mph year-round, and February is the windiest month, with hourly averages near 10 mph.
Elevation
+8°Fsummer afternoons at Saratoga, 2,605 ft down
Saratoga sits 2,605 ft lower, 4.5 miles away. Its summer highs average 8°F warmer and its winter lows 1°F milder than Castle Rock State Park.
Model resolution
2 placesshare one 3 km NOAA HRRR grid cell
Castle Rock State Park shares one 3 km grid cell in NOAA's HRRR model with Sanborn County Park. The hourly fog, wind, cloud, and temperature patterns on this site are the same for both. Real differences between them come from hills, elevation, and wind exposure that the model cannot resolve.
Daylight
9.6–14.7 hof daylight, Dec to Jun
Days at Castle Rock State Park range from about 9.6 hours in December to 14.7 hours in June. In mid-June the sun sets around 8:29 PM, and in mid-December around 4:56 PM.
Seasons at Castle Rock State Park
- Warm seasonJul 1 – Sep 27 · highs 77°F+
The warm season lasts about 2.9 months, from Jul 1 to Sep 27, when the average high is 77°F or warmer. Highs peak around Aug 8 at about 81°F.
- Cool seasonDec 3 – Mar 1 · highs 57°F or lower
The cool season runs from Dec 3 to Mar 1, when the average high is 57°F or lower. The coldest nights come around Dec 8, with an average low near 39°F.
- Rainy seasonOct 28 – Apr 21 · 90% of the year's rain
The rainy season runs from Oct 28 to Apr 21, when a day has at least a 22% chance of measurable rain. That stretch brings 90% of the year's rain.
The dark line marks today. Season dates come from the smoothed daily NOAA 1991-2020 normals. Counting from Oct. 1, a typical year has its first inch of rain by Oct 17 and half of its annual total by Jan 24.
Days per year and extremes (Nov 1, 2024 to Oct 31, 2026)
This record runs from Nov 1, 2024 to Oct 31, 2026. Over this record, Castle Rock State Park averaged no days at 90°F or hotter and 5 nights a year at or below freezing. It averaged 21 days a year with at least half an inch of rain and 4 afternoons with wind of 20 mph or more at 2 PM. About 77 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Sep 1, 2025 (89°F) and the coldest night was Feb 18, 2026 (29°F). The wettest day was Feb 5, 2025 (3.92 in.), and the strongest 2 PM gust was 50 mph on Mar 12, 2025.
- 0days at 90°F or hotter
- 5nights at or below freezing
- 21days with ½ in. of rain or more
- 4afternoons with 20+ mph wind
- 77mornings with 3+ hours of fog or low cloud
- Hottest day89°FSep 1, 2025
- Coldest night29°FFeb 18, 2026
- Wettest day3.92 inFeb 5, 2025
- Strongest 2 PM gust50 mphMar 12, 2025
What shapes Castle Rock State Park's weather
Castle Rock's ridge sits above the temperature inversion, a layer of warm air that caps the coastal fog and holds it down in the valleys. Above that lid, summer afternoons get warm on the exposed sandstone and chaparral. Summer afternoons here are also among the calmest of any Bay Area park.
In winter, Pacific storms rise over the Santa Cruz Mountains and drop far more rain on the crest than on the coast. Cloud often sits right on the ridge during storms. Wet sandstone is soft, which is why rain affects climbing access for days afterward.
Tips for visiting Castle Rock State Park
Plan climbing around the rain
Any measurable rain at the Kirkwood office can close climbing for up to three days, because the sandstone is much more fragile when damp.
Bring the dog to Sanborn instead
Dogs are prohibited at Castle Rock except service animals. State Parks points dog owners to nearby Sanborn County Park, which allows them.
Download maps before you drive up
There is no cell reception in or near the park, so download maps first and don't count on a phone signal or a rideshare out.
Know the day-use hours
Day use runs from 6 a.m. to sunset, and vehicles pay a day-use fee.
Book a trail camp for overnight trips
Backcountry trail camps are reservable. Fires are allowed only in designated rings at Castle Rock Trail Camp, and only during the rainy season.
Reserve parking if you continue to Big Basin
Big Basin parking is limited and reservations are strongly recommended. There is no cell service near the entrance kiosk, so download directions first.
Castle Rock State Park through the seasons
- Spring (March–May)
- Spring brings green ridges and mild days, but late storms can still close climbing for a few days after measurable rain.
- Summer (June–August)
- The ridge is usually sunny above the coastal fog. Midday on the exposed rock and chaparral can be hot, so start early.
- Fall (September–November)
- Fall is clear and dry, often with the best views of the year until the first rains. Dry brush on the ridge makes this the highest fire-danger stretch.
- Winter (December–February)
- Winter is the rainy season on the crest, with cloud often sitting on the ridge. Campfires are allowed at Castle Rock Trail Camp's designated rings only in the rainy season.
Activities and the weather that matters
- Rock climbing and bouldering: Climbing needs dry rock. It can be restricted for weather, and measurable rain closes it for up to three days.
- Hiking the ridge trails: Hiking is best on clear spring and fall days. On summer fog days the ridge trails rise above the gray for views over the fog.
- Backpacking toward Big Basin: The park's trails link to the Skyline to the Sea Trail. Dry-season trips avoid muddy trail, but summer afternoons on the exposed ridge are warm.
Official sources and current conditions
Numbers on this page come from NOAA data. The text draws on the official sources linked above.
Historical Climate Data
Long-term weather patterns and climate data
Data sources: Recent temperatures come from NOAA URMA and recent precipitation from NOAA Stage IV. Fog, cloud, wind, humidity, and sunshine come from NOAA HRRR, and long-term baselines from NOAA 1991-2020 climate normals.
Climate Overview
Based on NOAA 30-year temperature/rain normals (1991-2020) with recent fog/sun baseline
🌟 Best Months to Visit
⚠️ Challenging Months
Monthly Breakdown
| Month | Comfort | High/Low | ☀️ Sun | 🌫️ Fog | 💧 Rain | Perfect |
|---|---|---|---|---|---|---|
| November 2024 | 71 | 52° / 42.3° | 7h | 4d | 5.73" | 13 |
| December 2024 | 67 | 54.8° / 45.6° | 5.4h | 11d | 7.93" | 14 |
| January 2025 | 75 | 51.8° / 41.8° | 7h | 6d | 0.17" | 13 |
| February 2025 | 65 | 51.5° / 41.7° | 6.2h | 8d | 13.65" | 11 |
| March 2025 | 62 | 49.9° / 39.3° | 7.2h | 13d | 5.56" | 11 |
| April 2025 | 80 | 57.8° / 45.4° | 9.6h | 8d | 0.82" | 20 |
| May 2025 | 91 | 66.5° / 51.4° | 12.3h | 6d | 0.13" | 27 |
| June 2025 | 97 | 73.2° / 61.4° | 13h | 0d | 0" | 30 |
| July 2025 | 96 | 74.1° / 61.4° | 12.6h | 1d | 0" | 31 |
| August 2025 | 96 | 79.4° / 67° | 11.6h | 1d | 0" | 31 |
| September 2025 | 90 | 72° / 60° | 9.6h | 5d | 0.43" | 25 |
| October 2025 | 84 | 62.6° / 50.7° | 7.9h | 4d | 2.92" | 21 |
| November 2025 | 74 | 58.8° / 49.1° | 6.4h | 9d | 8.32" | 18 |
| December 2025 | 71 | 57.7° / 48.7° | 5.5h | 10d | 6.99" | 18 |
| January 2026 | 74 | 57.8° / 47.9° | 6.3h | 6d | 8.3" | 19 |
| February 2026 | 67 | 55.3° / 45.2° | 6.3h | 8d | 10.32" | 13 |
| March 2026 | 93 | 67.5° / 55.3° | 9.6h | 2d | 0" | 28 |
| April 2026 | 75 | 56.3° / 44.5° | 8.5h | 9d | 6.35" | 18 |
| May 2026 | 88 | 63.7° / 50.3° | 11.7h | 4d | 0.48" | 24 |
| June 2026 | 95 | 70.4° / 57.2° | 12.5h | 4d | 0" | 28 |
| July 2026 | 96 | 75.1° / 63.5° | 11.9h | 3d | 0.04" | 31 |
| August 2026 | 94 | 77.9° / 66.8° | 11.2h | 4d | 0" | 30 |
| September 2026 | 94 | 70.8° / 57.1° | 10.4h | 3d | 0.11" | 29 |
| October 2026 | 86 | 67.8° / 56.1° | 8.4h | 4d | 0.28" | 26 |
Climate Trends
Average Temperature by Month
About the Castle Rock State Park climate charts
The temperature chart compares average monthly highs and lows at Castle Rock State Park, showing both the seasonal cycle and the typical day-to-night range. The comfort chart summarizes how often the combined weather pattern is favorable rather than judging temperature alone.
Precipitation shows the total recorded or modeled rainfall for each month at Castle Rock State Park. Sunshine compares average bright-sky hours with the daylight available, while fog shows the average number of morning fog or low-cloud hours per day. Switch between the chart tabs to compare the same months across each measure.
Hourly Temperature, Fog, Wind, Cloud Cover, and Solar Radiation Patterns
Average local hour by month from 2014-09-30 to 2026-04-30
- Temperature: At Castle Rock State Park, the warmest typical hour is 3 PM in August (79°F). The coldest is 7 AM in February (43°F).
- Fog: Fog or low cloud covers Castle Rock State Park in 29% of 9 AM hours in May, the foggiest month. It usually thins to a third of that by 2 PM. July mornings are the least foggy (10%).
- Wind: Castle Rock State Park has no strong afternoon wind build-up. Afternoons average about 8 mph year-round, and February is the windiest month, with hourly averages near 10 mph.
- Cloud Cover: July middays are the clearest at Castle Rock State Park (10% average cloud cover), and March middays are the cloudiest (33%).
- Solar Radiation: The strongest typical sun at Castle Rock State Park comes at 1 PM in July, averaging 1007 W/m².
How to read the hourly heatmaps for Castle Rock State Park
This heatmap shows how average temperature at Castle Rock State Park changes by hour and month. Read left to right for the seasons and top to bottom for the time of day. Warmer colors mark the usual afternoon peaks, and cooler colors show overnight and winter lows.
This heatmap shows when fog or low cloud is most likely at Castle Rock State Park. Darker cells mark the months and hours when fog has been most common. They help separate overnight or morning fog from cloud that tends to linger into the afternoon.
This heatmap shows the typical hourly wind pattern at Castle Rock State Park through the year. It makes recurring afternoon wind, calmer overnight periods, and seasonal changes easier to compare than a single daily wind value.
This heatmap shows average cloud cover at Castle Rock State Park for every month and hour. Use it to see whether cloudiness is mainly an overnight and morning pattern or commonly persists during the part of the day you plan to visit.
This heatmap shows the average solar radiation reaching Castle Rock State Park by month and hour. Brighter cells indicate the strongest typical sun, while muted cells can reflect nighttime, shorter winter days, cloud cover, smoke, or terrain shading.
Each cell combines one month with one local hour. Hover over or focus on a cell for its value and sample coverage. The red marker shows the current month and hour.
How recent months compared at Castle Rock State Park
- October 2026 recap: October 2026 at Castle Rock State Park averaged a high of 68°F, 5°F warmer than October 2025 (63°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 43.8 in. of rain to Castle Rock State Park, 98% of the 45.0 in. normal.
Location Details
Castle Rock State Park weather questions
Everything you need to know about weather and visiting Castle Rock State Park
What is the weather like at Castle Rock State Park today?
It's 45°F at Castle Rock State Park right now, with a comfort score of 54 (fair). Today's forecast high at Castle Rock State Park is 51°F, 10°F below the mid November normal of 61°F. The best window today is 2 PM to 5 PM, at about 43°F with a 5 mph wind (comfort 42).
What is the best month to visit Castle Rock State Park?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Castle Rock State Park are July, September, and August. The best hours are usually 9 AM to noon in July, 3 PM to 6 PM in September, and 9 AM to noon in August. The warm season lasts about 2.9 months, from Jul 1 to Sep 27, when the average high is 77°F or warmer. Highs peak around Aug 8 at about 81°F.
What are the warmest and coldest months at Castle Rock State Park?
August is the warmest month at Castle Rock State Park, with an average high of 81°F. December is the coldest, with an average low of 39°F.
When does the fog burn off at Castle Rock State Park?
Fog or low cloud covers Castle Rock State Park in 29% of 9 AM hours in May, the foggiest month. It usually thins to a third of that by 2 PM. July mornings are the least foggy (10%).
How much rain does Castle Rock State Park get?
January is the wettest month (9.1 in.), out of about 45.0 in. a year. The rainy season runs from Oct 28 to Apr 21, when a day has at least a 22% chance of measurable rain. That stretch brings 90% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 43.8 in. of rain to Castle Rock State Park, 98% of the 45.0 in. normal.
How does Castle Rock State Park weather compare with Saratoga?
Saratoga sits 2,605 ft lower, 4.5 miles away. Its summer highs average 8°F warmer and its winter lows 1°F milder than Castle Rock State Park.
What kind of place is Castle Rock State Park?
Castle Rock State Park sits on one of the highest ridges in the Santa Cruz Mountains, along Highway 35 (Skyline Boulevard). It lies about 2½ miles southeast of the highway's junction with Highway 9 at Saratoga Gap. California State Parks manages it for its wind-sculpted sandstone, including the namesake Castle Rock that draws climbers. About 34 miles of trail connect to the Skyline to the Sea Trail and Big Basin. The canyons below hold redwood shade, but much of this park is open ridge with black oaks, knobcone pines and wide views.
What is Castle Rock State Park weather like in November?
November at Castle Rock State Park averages a high of 61°F and a low of 42°F, with 4.5 in. of rain over about 9 rainy days. About 15% of morning hours are foggy. Afternoon wind averages 8 mph.
More about Castle Rock State Park weather
Guides that explain the weather here and nearby
Data sources and methods
- Monthly temperatures and precipitation: NOAA 1991-2020 normals.
- Fog, cloud, wind, sun, and comfort by hour and month: NOAA's HRRR hourly analysis from September 2014 to April 2026.
- Daily records and recent months: NOAA URMA and HRRR analyses, plus NOAA Stage IV precipitation.
- Nearby comparisons and regional rankings use the same hourly HRRR summaries for every destination in the region.
- Alerts: National Weather Service. Tides and ocean temperature: NOAA CO-OPS, where shown.
- All statements on this page are computed from these datasets, apart from the “What shapes the weather” guide, which cites its sources inline.
- California State Parks, Castle Rock State Park (accessed 2026-10-27)
- California State Parks, Big Basin Redwoods State Park (accessed 2026-10-27)
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