Photo: Barkalow Brothers Co. / C.T. American Art · Public domainYermo reaches 100° on about 88 days a year, more than all but 83 U.S. towns
The depth of winter brings overnight lows near 36°. It is a dry place: less rain and snow fall here than on almost every U.S. town. Compared with 1901–2000, the average now sits 2.4° higher. Radiators earn their keep from December to January, the months that average under 50°.
A year in Yermo at a glance
Each month’s typical high and low, and what it brings.
What stands out about Yermo’s climate
Compared with towns across the U.S., with Yermo’s place in California beside it.
What a year in Yermo feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 279 frost-free days a year
In half of years the last 32° night comes by February 19 and the first by November 26. Frost and day counts come from NOAA’s station at Barstow Daggett Airport, 4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Yermo’s center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 23°. 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 4 inches of rain a year
February is the wettest month and June the driest. Rain falls on about 22 days a year. Snow is rare: about 0.2" in a normal year at Barstow Daggett Airport, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Yermo
39% of the work is heating, so air conditioning is the bigger bill. Months averaging under 55° run from December 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 Barstow Daggett Airport.
Living with Yermo’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
279 frost-free days in zone 9a. The last frost comes by Feb 19 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 26.
Months with highs of 62–84° and lows of 40° or more: March, April, October and November. 0.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Yermo from natural hazards, river flooding is the largest share (46%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Yermo and similar climates
TownRatings has no climate map of the towns around Yermo yet.
Climates most like Yermo’s, 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 |
|---|---|---|---|---|
| Yermo, CA | 36° | 104° | 4" | 0.2" |
| Casa Grande, AZ | 39° | 106° | 8" | 0.0" |
| St. George, UT | 33° | 103° | 8" | 1.2" |
| Moapa Valley, NV | 37° | 108° | 6" | 0.0" |
| Monahans, TX | 30° | 98° | 12" | 0.7" |
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 Yermo averaged 2.4° warmer than the 1900s. The biggest change is in September (+3.3°).
A bigger shift than in all but 113 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 Yermo compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Yermo’s place among California’s.
Yermo weather by month
Highs, lows and precipitation from NOAA’s grid at Yermo’s center; snow, wet days and snow on the ground from Barstow Daggett Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 62° | 36° | 0.6" | 0.0" | 4 | 0 | 44° – 55° |
| February | 66° | 40° | 0.7" | 0.0" | 4 | 0 | 47° – 59° |
| March | 73° | 45° | 0.4" | 0.0" | 3 | 0 | 52° – 65° |
| April | 79° | 50° | 0.2" | 0.0" | 2 | 0 | 59° – 69° |
| May | 88° | 58° | 0.0" | 0.0" | 1 | 0 | 65° – 80° |
| June | 99° | 66° | 0.0" | 0.0" | 0 | 0 | 76° – 88° |
| July | 104° | 73° | 0.3" | 0.0" | 2 | 0 | 84° – 92° |
| August | 103° | 72° | 0.2" | 0.0" | 1 | 0 | 84° – 91° |
| September | 96° | 65° | 0.2" | 0.0" | 1 | 0 | 76° – 84° |
| October | 83° | 53° | 0.2" | 0.0" | 1 | 0 | 64° – 74° |
| November | 70° | 42° | 0.3" | 0.0" | 2 | 0 | 48° – 62° |
| December | 60° | 35° | 0.6" | 0.2" | 3 | 0 | 44° – 52° |
| Year | 82° | 53° | 3.5" | 0.2" | 22 | 0 |
How much a month can swing
A normal is an average. May swings the most: from 1991 to 2020 its average ranged from 65° to 80°. August is the most reliable, staying within 7°.
Where Yermo’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 Yermo’s center.
- Snow: Barstow Daggett Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Barstow Daggett Airport, 4 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 Yermo’s climate
What is the weather like in Yermo?
A typical July afternoon reaches 104°, a January night drops to 36°, and snow is almost unheard of. Milder January nights than 83% of U.S. towns; hotter July afternoons than all but 79 U.S. towns.
How cold does it get in Yermo in winter?
December nights average 35°. About 24 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 44°.
How much snow does Yermo get?
About 0.2 inches in a normal winter at Barstow Daggett Airport, so most winters see none.
How hot does it get in Yermo?
July, with a typical high of 104° and a low of 73°. About 145 days a year reach 90° and 88 reach 100° (Barstow Daggett Airport).
When is the first and last frost in Yermo?
In half of years the last spring frost (32°) comes by February 19 and the first fall frost by November 26, about 279 frost-free days, at Barstow Daggett Airport.
What growing zone is Yermo in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 23°.
What is the best time of year to visit Yermo?
By one simple rule (highs of 62–84° and lows of 40° or more), March, April, October and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Yermo getting warmer?
Yes: 1991–2020 averaged 2.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than all but 113 U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Yermo.
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.