Photo: Frank Schulenburg · CC BY-SA 4.0Palermo reaches 100° on about 23 days a year, more than 96% of U.S. towns
A typical July afternoon reaches 96°, a January night drops to 39°.
A year in Palermo at a glance
Each month’s typical high and low, and what it brings.
What stands out about Palermo’s climate
Compared with towns across the U.S., with Palermo’s place in California beside it.
What a year in Palermo feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 321 frost-free days a year
In half of years the last 32° night comes by January 30 and the first by December 13. Frost and day counts come from NOAA’s station at Oroville, CA, 6 miles from the town’s center, at about the same height.
The 2023 USDA map puts Palermo’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°
90° days by month
Average days at 90° or more
About 27 inches of rain a year
February is the wettest month and July the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Palermo
57% of the work is heating. Months averaging under 55° run from November through February.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Oroville, CA.
Living with Palermo’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
321 frost-free days in zone 9b. The last frost comes by Jan 30 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 13.
Months with highs of 62–84° and lows of 40° or more: March, April, May, October and November. 1.0 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Palermo from natural hazards, river flooding is the largest share (54%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Palermo and its neighbors
Every town next door is within a degree of Palermo 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 Palermo averaged 1.2° warmer than the 1900s. The biggest change is in January (+2.4°).
A smaller shift than in 64% 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 Palermo compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Palermo’s place among California’s.
Palermo weather by month
Highs, lows and precipitation from NOAA’s grid at Palermo’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 56° | 39° | 5.0" | 44° – 54° |
| February | 62° | 42° | 5.2" | 47° – 57° |
| March | 67° | 44° | 4.1" | 49° – 61° |
| April | 73° | 47° | 2.0" | 54° – 64° |
| May | 82° | 54° | 1.2" | 58° – 75° |
| June | 90° | 59° | 0.4" | 69° – 80° |
| July | 96° | 63° | 0.0" | 76° – 83° |
| August | 95° | 62° | 0.1" | 75° – 82° |
| September | 90° | 58° | 0.2" | 70° – 78° |
| October | 79° | 51° | 1.5" | 61° – 71° |
| November | 65° | 44° | 2.9" | 47° – 60° |
| December | 56° | 39° | 4.9" | 44° – 51° |
| Year | 76° | 50° | 27.4" |
How much a month can swing
A normal is an average. May swings the most: from 1991 to 2020 its average ranged from 58° to 75°. August is the most reliable, staying within 7°.
Where Palermo’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 Palermo’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Oroville, CA, 6 miles from the town’s center, at about the same height; 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 Palermo’s climate
What is the weather like in Palermo?
A typical July afternoon reaches 96°, a January night drops to 39°. Milder January nights than 87% of U.S. towns; hotter July afternoons than 97% of U.S. towns.
How cold does it get in Palermo in winter?
December nights average 39°. About 16 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 44°.
How hot does it get in Palermo?
July, with a typical high of 96° and a low of 63°. About 97 days a year reach 90° and 23 reach 100° (Oroville, CA).
When is the first and last frost in Palermo?
In half of years the last spring frost (32°) comes by January 30 and the first fall frost by December 13, about 321 frost-free days, at Oroville, CA.
What growing zone is Palermo 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 Palermo?
By one simple rule (highs of 62–84° and lows of 40° or more), March, April, May, October and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Palermo getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 64% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Palermo.
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.