Precipitation in Posey trails that of 92% of U.S. towns: 17 inches a year
The coldest hours of a January night bottom out at 35° on average. Rain follows the seasons: January brings about 55 times as much as July. Its July heat outdoes that of 92% of U.S. towns. The frost-free window for a garden runs roughly May 11 to October 17.
A year in Posey at a glance
Each month’s typical high and low, and what it brings.
What stands out about Posey’s climate
Compared with towns across the U.S., with Posey’s place in California beside it.
What a year in Posey feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 155 frost-free days a year
In half of years the last 32° night comes by May 11 and the first by October 17. Frost and day counts come from Glennville, CA, 6 miles away.
The 2023 USDA map puts Posey’s center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 21°. 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 17 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 Posey
90% of the work is heating, so the furnace matters far more than the air conditioner. 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 Glennville, CA.
Living with Posey’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
155 frost-free days in zone 9a. The last frost comes by May 11 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 17.
Months with highs of 62–84° and lows of 40° or more: April, May and October.
Parks & trails →Of the yearly building losses FEMA expects in Posey from natural hazards, wildfire is the largest share (36%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Posey and similar climates
TownRatings has no climate map of the towns around Posey 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 Posey averaged 1.9° warmer than the 1900s. The biggest change is in January (+2.5°).
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 Posey compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Posey’s place among California’s.
Posey weather by month
Highs, lows and precipitation from NOAA’s grid at Posey’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 58° | 35° | 3.3" | 42° – 52° |
| February | 58° | 36° | 3.1" | 41° – 54° |
| March | 62° | 38° | 2.8" | 43° – 56° |
| April | 67° | 41° | 1.3" | 49° – 58° |
| May | 76° | 48° | 0.6" | 54° – 69° |
| June | 86° | 55° | 0.1" | 64° – 75° |
| July | 93° | 62° | 0.1" | 73° – 81° |
| August | 93° | 61° | 0.1" | 73° – 80° |
| September | 87° | 56° | 0.1" | 67° – 76° |
| October | 76° | 48° | 0.5" | 58° – 67° |
| November | 64° | 39° | 1.5" | 44° – 56° |
| December | 57° | 34° | 3.0" | 42° – 49° |
| Year | 73° | 46° | 16.6" |
How much a month can swing
A normal is an average. May swings the most: from 1991 to 2020 its average ranged from 54° to 69°. December is the most reliable, staying within 7°.
Where Posey’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 Posey’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Glennville, CA, 6 miles from the town’s center, 590 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 Posey’s climate
What is the weather like in Posey?
A typical July afternoon reaches 93°, a January night drops to 35°. Milder January nights than 80% of U.S. towns; hotter July afternoons than 92% of U.S. towns.
How cold does it get in Posey in winter?
December nights average 34°. About 108 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 42°.
How hot does it get in Posey?
July, with a typical high of 93° and a low of 62°. About 50 days a year reach 90° and 2 reach 100° (Glennville, CA).
When is the first and last frost in Posey?
In half of years the last spring frost (32°) comes by May 11 and the first fall frost by October 17, about 155 frost-free days, at Glennville, CA.
What growing zone is Posey in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 21°.
What is the best time of year to visit Posey?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Posey 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 Posey.
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.