Few U.S. towns have cooler summers than Fieldbrook
The coldest hours of a January night bottom out at 40° on average. By precipitation alone, it ranks wetter than 93% of U.S. towns. January has warmed most since 1901–2000, part of a 1.5° rise. Radiators earn their keep from November to March, the months that average under 50°.
A year in Fieldbrook at a glance
Each month’s typical high and low, and what it brings.
What stands out about Fieldbrook’s climate
Compared with towns across the U.S., with Fieldbrook’s place in California beside it.
What a year in Fieldbrook feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 262 frost-free days a year
In half of years the last 32° night comes by March 8 and the first by November 30. Frost and day counts come from Arcata Eureka Airport, 5 miles away.
The 2023 USDA map puts Fieldbrook’s center in zone 9b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 27°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 55 inches of rain a year
December is the wettest month and July the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Fieldbrook
Nearly all of the work is heating: a normal year has almost no cooling days. 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 Arcata Eureka Airport.
Living with Fieldbrook’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
262 frost-free days in zone 9b. The last frost comes by Mar 8 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 30.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August, September and October. 5.7 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Fieldbrook from natural hazards, river flooding is the largest share (47%). Normals are averages; the hazards page covers the extremes.
Natural hazards →Fieldbrook and its neighbors
Every town next door is within a degree of Fieldbrook in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Fieldbrook averaged 1.5° warmer than the 1900s. The biggest change is in January (+2.5°).
A bigger shift than in 61% 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 Fieldbrook compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Fieldbrook’s place among California’s.
Fieldbrook weather by month
Highs, lows and precipitation from NOAA’s grid at Fieldbrook’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 54° | 40° | 8.9" | 42° – 52° |
| February | 56° | 40° | 7.6" | 44° – 52° |
| March | 58° | 41° | 7.8" | 46° – 53° |
| April | 61° | 42° | 4.9" | 48° – 57° |
| May | 65° | 46° | 2.6" | 52° – 59° |
| June | 69° | 49° | 1.0" | 55° – 63° |
| July | 74° | 53° | 0.2" | 60° – 66° |
| August | 74° | 53° | 0.2" | 61° – 67° |
| September | 74° | 50° | 0.9" | 59° – 65° |
| October | 67° | 46° | 3.3" | 53° – 61° |
| November | 58° | 42° | 6.6" | 43° – 53° |
| December | 52° | 39° | 10.9" | 41° – 51° |
| Year | 63° | 45° | 54.8" |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from 42° to 52°. July is the most reliable, staying within 6°.
Where Fieldbrook’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 Fieldbrook’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Arcata Eureka Airport, 5 miles from the town’s center, 240 ft lower; no station nearby passes every check; this is the nearest one in the same valley, flagged above.
- 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 Fieldbrook’s climate
What is the weather like in Fieldbrook?
A typical July afternoon reaches 74°, a January night drops to 40°. Milder January nights than 88% of U.S. towns; cooler July afternoons than all but 152 U.S. towns.
How cold does it get in Fieldbrook in winter?
December nights average 39°. About 19 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 41°.
How hot does it get in Fieldbrook?
July, with a typical high of 74°. 90° days are rare: none in a normal year at Arcata Eureka Airport.
When is the first and last frost in Fieldbrook?
In half of years the last spring frost (32°) comes by March 8 and the first fall frost by November 30, about 262 frost-free days, at Arcata Eureka Airport.
What growing zone is Fieldbrook in?
Zone 9b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 27°.
What is the best time of year to visit Fieldbrook?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Fieldbrook getting warmer?
Yes: 1991–2020 averaged 1.5° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 61% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Fieldbrook.
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.