Photo: John Pilge · Public domainBoulder Creek’s winters are milder than most of the U.S.; July afternoons average 81°
A typical July afternoon reaches 81°, a January night drops to 39°.
A year in Boulder Creek at a glance
Each month’s typical high and low, and what it brings.
What stands out about Boulder Creek’s climate
Compared with towns across the U.S., with Boulder Creek’s place in California beside it.
What a year in Boulder Creek feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 310 frost-free days a year
In half of years the last 32° night comes by February 2 and the first by December 6. Frost and day counts come from NOAA’s station at Los Gatos, CA, 11 miles from the town’s center, 430 ft lower.
The 2023 USDA map puts Boulder Creek’s center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 24°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 40 inches of rain a year
January is the wettest month and July the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Boulder Creek
80% of the work is heating. Months averaging under 55° run from November through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Los Gatos, CA.
Living with Boulder Creek’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
310 frost-free days in zone 9a. The last frost comes by Feb 2 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Dec 6.
Months with highs of 62–84° and lows of 40° or more: March, April, May, June, July, August, September, October and November. 25 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Boulder Creek from natural hazards, river flooding is the largest share (64%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Boulder Creek and similar climates
TownRatings has no climate map of the towns around Boulder Creek yet.
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Boulder Creek averaged 1.9° warmer than the 1900s. The biggest change is in August (+2.4°).
A bigger shift than in 85% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Boulder Creek compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Boulder Creek’s place among California’s.
Boulder Creek weather by month
Highs, lows and precipitation from NOAA’s grid at Boulder Creek’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 60° | 39° | 8.3" | 46° – 55° |
| February | 60° | 40° | 7.7" | 47° – 56° |
| March | 64° | 42° | 6.0" | 47° – 59° |
| April | 67° | 43° | 2.8" | 51° – 58° |
| May | 71° | 47° | 1.1" | 55° – 63° |
| June | 77° | 49° | 0.3" | 59° – 66° |
| July | 81° | 53° | 0.0" | 63° – 70° |
| August | 82° | 53° | 0.0" | 65° – 72° |
| September | 81° | 52° | 0.1" | 63° – 71° |
| October | 75° | 48° | 1.7" | 58° – 67° |
| November | 65° | 42° | 4.0" | 47° – 57° |
| December | 59° | 39° | 8.1" | 45° – 52° |
| Year | 70° | 45° | 40.2" |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 47° to 59°. July is the most reliable, staying within 7°.
Where Boulder Creek’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Boulder Creek’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Los Gatos, CA, 11 miles from the town’s center, 430 ft lower; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Boulder Creek’s climate
What is the weather like in Boulder Creek?
A typical July afternoon reaches 81°, a January night drops to 39°. Milder January nights than 88% of U.S. towns; cooler July afternoons than 89% of U.S. towns.
How cold does it get in Boulder Creek in winter?
December nights average 39°. About 13 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 45°.
How hot does it get in Boulder Creek?
July, with a typical high of 81° and a low of 53°. About 27 days a year reach 90° and 2 reach 100° (Los Gatos, CA).
When is the first and last frost in Boulder Creek?
In half of years the last spring frost (32°) comes by February 2 and the first fall frost by December 6, about 310 frost-free days, at Los Gatos, CA.
What growing zone is Boulder Creek in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 24°.
What is the best time of year to visit Boulder Creek?
By one simple rule (highs of 62–84° and lows of 40° or more), March, April, May, June, July, August, September, October and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Boulder Creek getting warmer?
Yes: 1991–2020 averaged 1.9° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 85% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Boulder Creek.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.