Imperial County, CA Climate: Temperature & Rain by Month
Temperature and precipitation from NOAA NCEI 1991–2020 normals →, plus PlainClimate's derived comfort score
30-year climate normals (1991-2020) from Imperial County's primary NOAA station, IMPERIAL CO AP.
The climate verdict for Imperial County
Imperial County, California is cooling-led and dry. Its 2.4 inches of annual precipitation pairs with an annual average of 74°F. It scores 76/100 for climate comfort (good), putting it in the top third of station-mapped location scores and exceeding 69% of them.
- 74°F
- annual average temperature (NOAA normal)
- 76/100
- comfort score, above 69% of station-mapped location scores
- 2.4"
- yearly precipitation total
- 344 days
- frost-free growing season
Imperial County: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00003144 · Imperial County, CA 74°F mean · 2.4" precip
TEMP-HOT · RANK-WARM · PHOTO-FINISH · PRCP-ARID · SWING-MID · COMF-TOP · LOAD-COOL · STN-1 · BOOK-FULL
- TEMP-HOT 74°F
- RANK-WARM #6,724
- PHOTO-FINISH ≈ Brawley
- PRCP-ARID 2.4"
- SWING-MID 39°F
- COMF-TOP 76/100
- LOAD-COOL 4,162 CDD
- STN-1 USW00003144
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Brawley, CA (+ 0.1 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every CA station list.
- Imperial County (this station) 74°F
- Cold Ajo, AZ 74°F
- Hot Del Rio, TX 74°F
- Near Brawley, CA 74°F
- Near El Centro Naf, CA 74°F
Climate Living Index · Imperial County
Imperial County: 57/100 · grade C
Imperial County publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals · NOAA hourly normals); 1 missing weight rescale to 100.
PlainClimate-derived for Imperial County, not an official NOAA rating. Rankings still use Comfort Score 76/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Frost-free season | 344 days/year | 100/100 · A |
| Summer moisture balance | 56.7°F mean dew point | 83/100 · B |
| Annual temperature balance | 73.7°F · 6.2° from 67.5°F | 81/100 · B |
| Normal heat + freeze calendar | 168 calendar days | 34/100 · F |
| Precipitation balance | 2.4 in · 32.6 from 35 in | 0/100 · F |
Imperial County · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Imperial County's normals sit in a dry climate class: BWh
Annual precipitation falls well below the aridity threshold for this temperature regime, so the normals classify as hot desert (BWh). Class BWh is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: dry (arid or semi-arid), specifically hot desert.
- Köppen code
- BWh
- Group
- Dry (arid or semi-arid)
- Warmest month
- 93.6°F
- Coldest month
- 54.9°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · cooling-led station
Where Imperial County sits across the climate record
Three NOAA fields for Imperial County's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Top 2% warmest
- Among 6,861 stations, Imperial County sits in the warmer third of annual means.
- Annual precipitation
- Drier than 100%
- Imperial County's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- Narrower than 70%
- Warmest-to-coldest month gap for Imperial County is compact versus 6,861 complete station-years.
How Imperial County compares across U.S. station-mapped locations
Imperial County's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
76 Top 31% score exceeds 69% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). Below this entry.
- 70–80: 650 station-mapped locations (11%). This entry sits in this band.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Imperial County's measured station temperature trend
MethodologyAcross 35 complete annual observations from 1963 to 2023, IMPERIAL CO AP warmed at a fitted rate of 0.32°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Imperial County primary station fitted change +0.32 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 71°F (21°C) | 42°F (5°C) | 56°F (13°C) | 0.4" | 1.3 | 0.0 |
| February | 74°F (23°C) | 45°F (7°C) | 59°F (15°C) | 0.4" | 0.7 | 0.0 |
| March | 80°F (27°C) | 51°F (10°C) | 65°F (19°C) | 0.3" | 0.0 | 5.2 |
| April | 86°F (30°C) | 56°F (13°C) | 71°F (22°C) | 0.1" | 0.0 | 11.1 |
| May | 94°F (35°C) | 62°F (17°C) | 78°F (26°C) | 0.1" | 0.0 | 23.2 |
| June | 104°F (40°C) | 70°F (21°C) | 87°F (30°C) | 0.0" | 0.0 | 29.8 |
| July | 108°F (42°C) | 78°F (26°C) | 93°F (34°C) | 0.1" | 0.0 | 31.0 |
| August | 108°F (42°C) | 79°F (26°C) | 94°F (34°C) | 0.1" | 0.0 | 30.9 |
| September | 102°F (39°C) | 72°F (22°C) | 87°F (31°C) | 0.2" | 0.0 | 28.7 |
| October | 90°F (32°C) | 60°F (16°C) | 75°F (24°C) | 0.2" | 0.0 | 19.1 |
| November | 78°F (26°C) | 48°F (9°C) | 63°F (17°C) | 0.2" | 0.3 | 2.1 |
| December | 69°F (20°C) | 41°F (5°C) | 55°F (13°C) | 0.3" | 1.8 | 0.0 |
The year, day by day
The year in Imperial County runs from a mild 41°F around December 21 to 108°F at the peak near July 15, and the normal low never reaches freezing on any date in the record.
When the heat sits
Normal highs reach 90°F from May 2 through October 16, covering 168 dates. The broader mild season, normal highs of 70°F or more, runs January 11 to December 5.
This counts calendar dates whose 1991–2020 normal high reaches 90°F. It is a smaller number than the 90°F+ day counts in the monthly table above, which measure how often the threshold was actually crossed in a typical year. A date can average 88°F and still exceed 90°F in half of all years.
No freezing date
Not one calendar date in the 1991–2020 record carries a normal low at or below 32°F. The coldest normal low of the year is 41°F around December 21.
Where the wet dates fall
The likeliest wet date is February 19, when 8% of years recorded at least a hundredth of an inch. The driest is June 10 at 0%. Summed across the calendar, that is about 13 wet dates a year.
The widest day
June 4 carries the biggest normal gap between afternoon and dawn, 34°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Imperial County.
Where Imperial County Stands Nationally
Summers here run among the most heat-heavy normals calendars in the country: on about 168 days a year the normal daily high itself reaches 90°F — a count fewer than one station in ten exceeds.
Aridity defines the water calendar: about 2 inches in a normal year lands this among the driest tenth of ranked stations.
Imperial County earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall
2.4 days with precipitation
1.9 days with precipitation
1.3 days with precipitation
0.7 days with precipitation
0.2 days with precipitation
0.0 days with precipitation
0.6 days with precipitation
1.0 days with precipitation
0.7 days with precipitation
1.0 days with precipitation
1.0 days with precipitation
1.9 days with precipitation
Imperial County's wet season runs through the cold months
December, January and February carry 47% of the year's precipitation here, while June through August contribute 11%. That is the cool-season-dominant pattern of the West Coast and the higher inland West, where storm tracks swing south in winter and summer turns dry; the thermometer meanwhile shows a 38.7°F seasonal spread.
- Wettest month
- January, 0.4"
- Driest month
- June, 0.0"
- Wettest three months
- January, February, December (47% of the year)
Shares are computed from this station's own 1991-2020 monthly precipitation normals. A cool-season label means the December-February share reaches 35%. Where snow falls, the monthly figures above report liquid-equivalent precipitation, so a wet winter month is not necessarily a rainy one.
Imperial County is dry, and what does fall arrives gently
Only about 13 days a year record measurable precipitation here, 3% of the calendar, and they carry 2.4" between them. At roughly 0.19 inches on an average wet day, this is not the damp drizzle of a marine climate; it is an arid record in which precipitation is both uncommon and light when it appears.
The wettest month by count is January at about 2 wet days; the driest is June at about 0.
A low per-event average in a dry record is a statement about typical days only. Arid regions can still take a large share of a year's total from a single convective storm, which a normal cannot show.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, not the extremes within it.
Frost Dates & Growing Season
First Fall Freeze
December 24
50% probability date
Last Spring Freeze
January 14
50% probability date
Growing Season
344 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
967
Higher = more heating needed
Cooling Degree Days
4,162
Higher = more cooling needed
Warmest Month
August
Coldest Month
December
Humidity & Wind
Monthly averages from hourly observations
| Month | Humidity | Wind (mph) | Clear Sky % | Overcast % |
|---|---|---|---|---|
| January | 45% | 5.8 | 70% | 8% |
| February | 42% | 7.5 | 68% | 8% |
| March | 35% | 8.7 | 77% | 4% |
| April | 30% | 9.6 | 80% | 2% |
| May | 28% | 8.8 | 82% | 2% |
| June | 27% | 8.2 | 84% | 1% |
| July | 34% | 7.5 | 77% | 2% |
| August | 36% | 6.7 | 76% | 2% |
| September | 32% | 6.6 | 85% | 1% |
| October | 35% | 6.0 | 81% | 2% |
| November | 42% | 5.3 | 75% | 6% |
| December | 46% | 5.0 | 70% | 10% |
Nationwide similar cities
Other rankable U.S. places outside CA closest to Imperial County on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (74°F here).
- Port Salerno, FL 74°F · 0.0°F off
- Quartzsite, AZ 74°F · 0.0°F off
- Venice, FL 74°F · 0.0°F off
- Clermont, FL 74°F · 0.1°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (2.4" here), excluding temperature-peer places.
- Yuma Proving Ground, AZ 3.5" · 1.2" off
- Wendover, UT 3.6" · 1.2" off
- Tacna, AZ 3.8" · 1.4" off
- Yuma, AZ 4.0" · 1.6" off
Scarce-water calendar
Where Imperial County's limited precipitation lands
cooling led · dry · mid swing
Air-conditioning demand is the clearest thermal signal here. Imperial County accumulates 4,162 cooling degree days, more than twice its 967 heating total; the monthly table shows when that imbalance builds rather than treating it as a year-round condition.
Heat demand sits beside limited local precipitation: Imperial County receives 2.4 inches in a normal year, inside PlainClimate's dry range. Snowfall is not added to the interpretation because its annual value is missing. Month-level precipitation is the useful check on when that small annual total arrives.
August and December mark the typical warm and cold ends of the calendar in Imperial County's middle-range seasonal profile. The measured spread is 38.7°F. The annual average is 74°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
With about 344 frost-free days, the calendar is constrained more by sustained heat than by freeze timing. This does not measure crop suitability or soil moisture; it only reports the NOAA-derived frost-free window for Imperial County.
Imperial County wettest normal
January
January concentrates the scarce annual total (2.4 inches).
Imperial County driest normal
June
June is typically driest; arid stations are defined by when water is absent, not by a four-season grid.
Questions about Imperial County's climate
How dry is Imperial County? ▼
How many days above 90°F does Imperial County get? ▼
How much energy does heating and cooling require in Imperial County? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Imperial County's primary station: IMPERIAL CO AP (USW00003144). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Imperial County; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Imperial County comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.