Riverside, CA Climate: Temperature & Rain by Month
Explore NOAA NCEI's 1991–2020 climate normals → and a clearly labeled PlainClimate comfort calculation
30-year climate normals (1991-2020) from Riverside's primary NOAA station, RIVERSIDE MUNI AP.
The climate verdict for Riverside
Dryness leads the climate profile for Riverside, California, with 9.4 inches of precipitation a year. NOAA records an annual average of 66°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.
- 66°F
- yearly average temperature, NOAA normal
- 76/100
- comfort score, above 69% of station-mapped location scores
- 9.4"
- precipitation, annual total
- 355 days
- growing season, frost-free days
Riverside: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00003171 · Riverside, CA 66°F mean · 9.4" precip
TEMP-MILD · RANK-WARM · PHOTO-FINISH · PRCP-ARID · SWING-NARROW · COMF-TOP · LOAD-MIX · STN-1 · BOOK-FULL
- TEMP-MILD 66°F
- RANK-WARM #6,175
- PHOTO-FINISH ≈ Anvil Rch
- PRCP-ARID 9.4"
- SWING-NARROW 25°F
- COMF-TOP 76/100
- LOAD-MIX H/C balanced
- STN-1 USW00003171
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Anvil Rch, AZ (+ 0 °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.
- Riverside (this station) 66°F
- Hot Crockett, TX 66°F
- Near Anvil Rch, AZ 66°F
- Near Bakersfield, CA 66°F
- Near Baxley, GA 66°F
Climate Living Index · Riverside
Riverside: 74/100 · grade B
Riverside publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Riverside, not an official NOAA rating. Rankings still use Comfort Score 76/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Frost-free season | 355 days/year | 100/100 · A |
| Annual temperature balance | 66.2°F · 1.3° from 67.5°F | 95/100 · A |
| Normal heat + freeze calendar | 86 calendar days | 80/100 · B |
| Precipitation balance | 9.4 in · 25.6 from 35 in | 10/100 · F |
Riverside · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Riverside's normals sit in a dry climate class: BSh
Precipitation is low relative to temperature but above true desert thresholds: hot semi-arid steppe (BSh). Class BSh is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: dry (arid or semi-arid), specifically hot semi-arid steppe.
- Köppen code
- BSh
- Group
- Dry (arid or semi-arid)
- Warmest month
- 79.8°F
- Coldest month
- 54.8°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 · balanced station
Where Riverside sits across the climate record
Three NOAA fields for Riverside's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Top 10% warmest
- Among 6,861 stations, Riverside sits in the warmer third of annual means.
- Annual precipitation
- Drier than 95%
- Riverside's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- Narrower than 94%
- Warmest-to-coldest month gap for Riverside is compact versus 6,861 complete station-years.
How Riverside compares across U.S. station-mapped locations
Riverside'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
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 68°F (20°C) | 44°F (6°C) | 56°F (13°C) | 2.3" | 1.1 | 0.2 |
| February | 68°F (20°C) | 45°F (7°C) | 56°F (13°C) | 2.4" | 0.6 | 0.1 |
| March | 72°F (22°C) | 47°F (8°C) | 60°F (15°C) | 1.2" | 0.3 | 1.0 |
| April | 76°F (24°C) | 50°F (10°C) | 63°F (17°C) | 0.6" | 0.0 | 2.7 |
| May | 80°F (27°C) | 55°F (13°C) | 68°F (20°C) | 0.2" | 0.0 | 5.5 |
| June | 87°F (30°C) | 59°F (15°C) | 73°F (23°C) | 0.0" | 0.0 | 12.1 |
| July | 93°F (34°C) | 64°F (18°C) | 79°F (26°C) | 0.1" | 0.0 | 23.8 |
| August | 95°F (35°C) | 65°F (18°C) | 80°F (27°C) | 0.0" | 0.0 | 25.2 |
| September | 91°F (33°C) | 62°F (17°C) | 77°F (25°C) | 0.1" | 0.0 | 18.9 |
| October | 83°F (28°C) | 55°F (13°C) | 69°F (21°C) | 0.3" | 0.0 | 9.0 |
| November | 75°F (24°C) | 47°F (9°C) | 61°F (16°C) | 0.6" | 0.2 | 2.0 |
| December | 67°F (19°C) | 43°F (6°C) | 55°F (13°C) | 1.5" | 1.3 | 0.0 |
The year, day by day
The year in Riverside runs from a mild 42°F around December 18 to 95°F at the peak near August 21, and the normal low never reaches freezing on any date in the record.
When the heat sits
Normal highs reach 90°F from June 27 through September 20, covering 86 dates. The broader mild season, normal highs of 70°F or more, runs March 4 to November 28.
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 42°F around December 18.
Where the wet dates fall
The likeliest wet date is February 20, when 24% of years recorded at least a hundredth of an inch. The driest is June 16 at 1%. Summed across the calendar, that is about 35 wet dates a year.
The widest day
August 30 carries the biggest normal gap between afternoon and dawn, 31°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Riverside.
Where Riverside Stands Nationally
Aridity defines the water calendar: about 9 inches in a normal year lands this among the driest tenth of ranked stations.
Heat is a defining feature of the normals calendar — the normal daily high reaches 90°F on roughly 86 days a year, more than four out of five ranked stations record.
Riverside earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall
4.8 days with precipitation
6.9 days with precipitation
5.2 days with precipitation
3.9 days with precipitation
1.6 days with precipitation
0.2 days with precipitation
0.7 days with precipitation
0.5 days with precipitation
0.5 days with precipitation
2.4 days with precipitation
3.6 days with precipitation
5.1 days with precipitation
Riverside's wet season runs through the cold months
December, January and February carry 66% of the year's precipitation here, while June through August contribute 2%. 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 an unusually narrow 25°F seasonal spread.
- Wettest month
- February, 2.4"
- Driest month
- June, 0.0"
- Wettest three months
- February, January, December (66% 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.
How Riverside's precipitation splits across the calendar
About 35 days a year record measurable precipitation here, carrying 9.4" between them, or roughly 0.26 inches on a typical wet day. That sits in the middle band: neither the many-light-days pattern of the Pacific Northwest and the Great Lakes, nor the few-heavy-events pattern of the Gulf and the desert Southwest.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year and say nothing about the heaviest single storm on record.
Frost Dates & Growing Season
First Fall Freeze
December 30
50% probability date
Last Spring Freeze
January 9
50% probability date
Growing Season
355 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
1,386
Higher = more heating needed
Cooling Degree Days
1,854
Higher = more cooling needed
Warmest Month
August
Coldest Month
December
Nationwide similar cities
Other rankable U.S. places outside CA closest to Riverside 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 (66°F here).
- Baxley, GA 66°F · 0.0°F off
- Crockett, TX 66°F · 0.0°F off
- El Paso, TX 66°F · 0.0°F off
- Homerville, GA 66°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (9.4" here), excluding temperature-peer places.
- Minden, NV 9.3" · 0.0" off
- Kemmerer, WY 9.4" · 0.0" off
- St George, UT 9.3" · 0.1" off
- Terlingua, TX 9.3" · 0.1" off
Scarce-water calendar
Where Riverside's limited precipitation lands
mixed demand · dry · low swing
Local precipitation is sparse in this otherwise mixed profile. The station reports 9.4 inches annually, within PlainClimate's dry band. Snowfall is not added to the interpretation because its annual value is missing. The monthly distribution matters because the total alone does not reveal the timing.
The calendar stays thermally compact and dry. August and December mark the typical warm and cold ends of the calendar, only 25.0°F apart, while the annual precipitation total remains below PlainClimate's dry threshold. The annual average is 66°F. The monthly rows show whether that limited precipitation is spread through the year or concentrated in a shorter interval.
Riverside combines a compact 25.0°F annual temperature range with meaningful demand on both sides of the thermostat: 1,386 heating and 1,854 cooling degree days. The balance matters more here than either annual total in isolation.
Riverside has a long frost-free window of roughly 355 days, but the dry annual profile is a separate constraint. Growing-season length says when freezes are unlikely, not whether rainfall is sufficient.
Riverside wettest normal
February
February concentrates the scarce annual total (9.4 inches).
Riverside driest normal
June
June is typically driest; arid stations are defined by when water is absent, not by a four-season grid.
Questions about Riverside's climate
How dry is Riverside? ▼
How many days above 90°F does Riverside get? ▼
How much energy does heating and cooling require in Riverside? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Riverside's primary station: RIVERSIDE MUNI AP (USW00003171). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 0662000). Match rule for Riverside: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Riverside 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.