Precipitation in Granite Hills trails that of 94% of U.S. towns: 14 inches a year
January nights here settle around 42°. Winters are mild: January nights here are milder than in 90% of U.S. towns. The latest 30-year average runs 2.1° warmer than 1901–2000’s, with January up the most. From October to June, highs of 68–83° make it easy to spend the day outdoors.
A year in Granite Hills at a glance
Each month’s typical high and low, and what it brings.
What stands out about Granite Hills’ climate
Compared with towns across the U.S., with Granite Hills’ place in California beside it.
What a year in Granite Hills feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
A freeze most winters
Frost and day counts come from NOAA’s station at El Cajon, CA, 1.3 miles from the town’s center, 240 ft lower.
The 2023 USDA map puts Granite Hills’ center in zone 10a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 35°. 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 14 inches of rain a year
February is the wettest month and July the driest. Rain falls on about 45 days a year. Snow is rare: about 0.0" in a normal year at Lakeside 2 E, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Granite Hills
49% of the work is heating, so air conditioning is the bigger bill. Months averaging under 55° run from December.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at El Cajon, CA.
Living with Granite Hills’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 10a. Frost comes about 7 winters in 10, so tender plants can often stay out through winter.
Months with highs of 62–84° and lows of 40° or more: January, February, March, April, May, June, October, November and December.
Parks & trails →Of the yearly building losses FEMA expects in Granite Hills from natural hazards, river flooding is the largest share (60%); heat waves, cold waves, winter storms and ice storms together are 3%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Granite Hills and its neighbors
Crest the hottest July afternoons (89°, 1° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Granite Hills’, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Granite Hills, CA | 42° | 88° | 14" | 0.0" |
| Sierra Vista Southeast, AZ | 32° | 91° | 15" | 0.7" |
| Alpine, TX | 30° | 90° | 15" | 2.2" |
| The Dalles, OR | 31° | 88° | 15" | 5.5" |
| Finley, WA | 29° | 91° | 9" | 2.0" |
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 Granite Hills averaged 2.1° warmer than the 1900s. The biggest change is in January (+3.2°).
A bigger shift than in 94% 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 Granite Hills compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Granite Hills’ place among California’s.
Granite Hills weather by month
Highs, lows and precipitation from NOAA’s grid at Granite Hills’ center; snow, wet days and snow on the ground from Lakeside 2 E, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 69° | 42° | 2.7" | 0.0" | 7 | 0 | 51° – 60° |
| February | 69° | 43° | 3.2" | 0.0" | 8 | 0 | 52° – 62° |
| March | 71° | 46° | 2.2" | 0.0" | 7 | 0 | 53° – 65° |
| April | 74° | 48° | 1.0" | 0.0" | 4 | 0 | 57° – 65° |
| May | 77° | 53° | 0.4" | 0.0" | 3 | 0 | 61° – 70° |
| June | 83° | 57° | 0.1" | 0.0" | 1 | 0 | 65° – 74° |
| July | 88° | 61° | 0.1" | 0.0" | 1 | 0 | 71° – 80° |
| August | 90° | 62° | 0.1" | 0.0" | 0 | 0 | 73° – 79° |
| September | 88° | 59° | 0.2" | 0.0" | 1 | 0 | 70° – 78° |
| October | 82° | 53° | 0.5" | 0.0" | 3 | 0 | 63° – 72° |
| November | 75° | 45° | 1.1" | 0.0" | 4 | 0 | 53° – 64° |
| December | 68° | 41° | 2.1" | 0.0" | 7 | 0 | 51° – 58° |
| Year | 78° | 51° | 13.6" | 0.0" | 45 | 0 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 53° to 65°. August is the most reliable, staying within 6°.
Where Granite Hills’ 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 Granite Hills’ center.
- Snow: Lakeside 2 E, CA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: El Cajon, CA, 1.3 miles from the town’s center, 240 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 Granite Hills’ climate
What is the weather like in Granite Hills?
A typical July afternoon reaches 88°, a January night drops to 42°, and snow is almost unheard of. Milder January nights than 90% of U.S. towns; hotter July afternoons than 67% of U.S. towns.
How cold does it get in Granite Hills in winter?
December nights average 41°. About 3 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 51°.
How much snow does Granite Hills get?
About 0.0 inches in a normal winter at Lakeside 2 E, CA, so most winters see none.
How hot does it get in Granite Hills?
July, with a typical high of 88° and a low of 61°. About 57 days a year reach 90° and 7 reach 100° (El Cajon, CA).
When is the first and last frost in Granite Hills?
There is no reliable frost date: a 32° night comes in about 73% of winters at El Cajon, CA, so most years bring a freeze but some pass without one.
What growing zone is Granite Hills in?
Zone 10a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 35°.
What is the best time of year to visit Granite Hills?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March, April, May, June, October, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Granite Hills getting warmer?
Yes: 1991–2020 averaged 2.1° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 94% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Granite Hills.
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.