Climate and average weather in Atascadero

In Atascadero, the summers are warm, dry, and clear and the winters are cool and mostly clear.

Best: late April to early November

Over the course of the year, the temperature in Atascadero typically varies from 42°F to 80°F, and is rarely below 35°F or above 88°F. August is the hottest month of the year, while December is the coldest.

Based on the travel score, the best time of year to visit Atascadero for warm-weather activities is from late April to early November.

Hottest
Aug
80°
Coldest
Dec
42°
Wettest
Jan
3.3 in
Driest
Jul
0.0 in
Rain / yr
15.0 in
39 wet days
Daylight
9.6–14.4 h
shortest–longest
Elevation
879 ft
35.5°N
Clearest
Aug
11% cloud

Atascadero is city in San Luis Obispo County, California, United States.

Density
441/km²
people per km²
Founded
1979

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Atascadero weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around late April to early November.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Atascadero, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 4.1 months, from June 7 to October 10, with daily high temperatures above 74°F. The hottest month of the year in Atascadero is August, with an average high of 80°F and low of 59°F.

The cool season lasts 3.4 months, from November 25 to March 8, with daily high temperatures below 62°F. The coldest month of the year in Atascadero is December, with an average low of 42°F and high of 59°F.

Days typically run about 19°F warmer than nights year-round.

40°60°80°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°F)Avg low (°F)
Jan5943
Feb6044
Mar6346
Apr6748
May7151
Jun7655
Jul7959
Aug8059
Sep7857
Oct7353
Nov6547
Dec5942

Average hourly temperature in Atascadero

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on August afternoons, near 80°F, and coldest before dawn in December, near 42°F.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Atascadero weather by month

Every month at a glance. Click a month for its detailed page.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan59° / 43°3.37.19.95.0
Feb60° / 44°3.37.710.75.2
Mar63° / 46°2.56.411.76.3
Apr67° / 48°0.93.512.97.5
May71° / 51°0.41.713.88.5
Jun76° / 55°0.10.414.49.4
Jul79° / 59°0.00.114.29.2
Aug80° / 59°0.00.213.39.1
Sep78° / 57°0.10.412.29.2
Oct73° / 53°0.7211.18.8
Nov65° / 47°1.13.610.17.1
Dec59° / 42°2.56.29.65.1

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Atascadero gets about 15.0 in of precipitation a year. On a typical day the chance of rain is mostly dry, but that rises and falls sharply with the seasons.

The wetter season lasts 5.4 months, from around Nov 7 to Apr 18, peaking in February at about 29% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jul 29.

January is the wettest month by volume, with 3.3 in over about 7 wet days; July is the driest, with 0.0 in.

0%10%20%30%40%JanFebMarAprMayJunJulAugSepOctNovDecwetterdrierwettermostly drysome rainoften wetFeb 19 · 29%Jul 29 · 0%
Rain on a day (%)Rain days
Jan237
Feb278
Mar216
Apr124
May62
Jun10
Jul10
Aug10
Sep20
Oct62
Nov124
Dec206

Monthly rainfall

Over a full year, Atascadero collects about 15.0 in of rain across 39 wet days — roughly 1.2 in in an average month.

It doesn’t fall evenly. January is the wettest month with 3.3 in, while July is the driest at just 0.0 in. The three wettest months alone bring about 61% of the year’s total.

00.511.522.533.54JanFebMarAprMayJunJulAugSepOctNovDec3.33.32.50.90.40.10.00.00.10.71.12.5
Rainfall (in)Rain days
Jan3.37
Feb3.38
Mar2.56
Apr0.94
May0.42
Jun0.10
Jul0.00
Aug0.00
Sep0.10
Oct0.72
Nov1.14
Dec2.56

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Atascadero, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.

The clearer part of the year begins around April 30 and lasts for 6.1 months, ending around November 2. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 96% of the time on average.

The cloudier part of the year begins around November 3 and lasts for 5.8 months, ending around April 29. The cloudiest month is February, when it is overcast or mostly cloudy 43% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecAug 25 · 97%Feb 13 · 56%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan5743
Feb5743
Mar6238
Apr7327
May8218
Jun937
Jul946
Aug964
Sep946
Oct8614
Nov7030
Dec6040

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 12, brings about 14 h 24 min of light; the shortest, around January 1, only 9 h 36 min — a swing of roughly 4 h 48 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan9.97:175:07
Feb10.76:575:37
Mar11.76:216:04
Apr12.95:366:30
May13.85:036:55
Jun14.44:517:14
Jul14.25:037:14
Aug13.35:266:47
Sep12.25:506:04
Oct11.16:155:20
Nov10.16:454:51
Dec9.67:104:47

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Atascadero averages about 20 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 12 and 28 days.

The sunnier stretch runs 5.9 months, from around May 8 to Nov 2. The sunniest month is September, with roughly 27 sunny days (brilliant).

The greyest month is March, down near 13 sunny days — about 51% fewer than the September peak.

05101520253035JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedbrightbrilliantSep 428 daysMar 312 days
Sunny daysSky
Jan13Mixed
Feb11Mixed
Mar14Mixed
Apr17Bright
May22Bright
Jun26Brilliant
Jul28Brilliant
Aug28Brilliant
Sep27Brilliant
Oct24Brilliant
Nov17Bright
Dec14Mixed

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

In Atascadero, the air stays dry or comfortable essentially all year. Even in August, the muggiest month, it feels humid or worse only about 10% of the time — humidity is not something you need to plan around here.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJan 15 · 100%Aug 4 · 90%humidcomfortabledrycomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)
Jan99100
Feb100100
Mar99100
Apr99100
May95500
Jun841600
Jul494560
Aug345691
Sep534250
Oct821710
Nov98200
Dec99100

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Atascadero is typically calm, near 5 mph, and varies little with the seasons.

The windier part of the year lasts 6.8 months, from around Nov 21 to Jun 16. The windiest month is April, averaging about 6 mph (calm).

The calmer part of the year runs from around Jun 17 to Nov 20, with August the calmest month at about 4 mph.

0510JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezeApr 16 · 6 mphAug 24 · 4 mph
Wind speed (mph)Feels
Jan5calm
Feb5calm
Mar5calm
Apr6calm
May6calm
Jun5calm
Jul4calm
Aug4calm
Sep4calm
Oct4calm
Nov5calm
Dec5calm

Best time to visit Atascadero

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Atascadero throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around late October, Atascadero is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 64°F and 82°F. Based on this score, the best time of year to visit Atascadero for general outdoor tourist activities is from late April to early November, with a peak score in the third week of June.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timetravel scoretemperaturecloudsprecipitationJun 17 · 9.5

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan5.0fair
Feb5.2fair
Mar6.2good
Apr7.5good
May8.5ideal
Jun9.3ideal
Jul9.2ideal
Aug9.1ideal
Sep9.3ideal
Oct8.8ideal
Nov7.1good
Dec5.1fair

The beach/pool score favors clear, rainless days with daytime highs between 75°F and 93°F. Based on this score, the best time of year to visit Atascadero for hot-weather activities is from early June to mid October, with a peak score in the second week of August.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationAug 10 · 8.8

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for Atascadero, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

For a warm-season trip around August (highs near 80°F), the essentials are light clothes and sun protection. In the cold season around December (highs near 59°F), pack a warm layer.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In August, Atascadero sees daytime highs around 80°F and nights near 59°F. Pack sun protection. Worth having: light clothes.

Sea temperature near Atascadero

Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.

The sea at the nearest coast (about 14 mi away) is warmest in September at about 60°F and coldest in April near 54°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

52°54°56°58°60°62°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan56Bracing
Feb56Bracing
Mar55Bracing
Apr54Bracing
May54Bracing
Jun56Bracing
Jul58Bracing
Aug59Cool
Sep60Cool
Oct60Cool
Nov58Bracing
Dec57Bracing

UV index (midday) in Atascadero by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

Under clear skies, the midday UV index in Atascadero peaks around June 21 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 21UV 11Dec 14UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5Moderate
Apr7High
May8Very high
Jun11Extreme
Jul10Extreme
Aug10Extreme
Sep7Very high
Oct6High
Nov3Moderate
Dec3Moderate

Average hourly UV index in Atascadero

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in June the burn window is concentrated in the middle of the day: about 9 hours a day reach index 3 (protection recommended), and 6 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan1.50
Feb40
Mar50
Apr73
May85
Jun96
Jul8.56
Aug85.5
Sep6.53.5
Oct50
Nov00
Dec00

Air quality in Atascadero by month

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.

Air quality in Atascadero is worst in August — around 19 µg/m³ PM2.5 (moderate), about 4.5× the cleanest month (June, 4 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 2218 µg/m³Jun 124 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb6Good
Mar7Good
Apr6Good
May5Good
Jun4Good
Jul7Good
Aug19Moderate
Sep17Moderate
Oct7Good
Nov6Good
Dec5Good
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

Atascadero is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecfrost-free year round
Frost-free chance (%)Frost nights
Jan980
Feb990
Mar1000
Apr1000
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct1000
Nov1000
Dec980

Growing degree days

Degree days (base 50°F)Frost-free shaded

Growing degree days tally heat above 50°F: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Atascadero banks about 3,550 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.

01,0002,0003,0004,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°F·days)
Jan28
Feb56
Mar133
Apr212
May350
Jun465
Jul579
Aug600
Sep529
Oct403
Nov172
Dec22

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Atascadero receives about 5.6 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 2.7 and 8.3 kWh/m².

The brighter stretch of the year lasts 6.2 months, from around Mar 23 to Sep 28. The brightest month is June, averaging about 8.2 kWh/m² (intense).

The dimmest month is December, down near 2.7 kWh/m² — roughly 67% less than the June peak.

0123456789JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseJun 218.3 kWhDec 152.7 kWh
Solar energy (kWh/m²)Level
Jan2.9Moderate
Feb3.8Moderate
Mar5.2Bright
Apr6.8Intense
May7.7Intense
Jun8.3Intense
Jul8.0Intense
Aug7.4Intense
Sep6.2Intense
Oct4.7Bright
Nov3.4Moderate
Dec2.7Moderate

Where is Atascadero?

Atascadero sits at 35.5°N, 120.7°W, 879 ft above sea level, in United States. The nearest listed city is Paso Robles, 9.3 mi away.

Topography around Atascadero

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Atascadero.

Within 2 miles, the terrain around Atascadero has only modest variations in elevation — a maximum elevation change of 600 ft around an average of 948 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,549 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,698 ft.

The land around Atascadero is covered by trees (39%), grassland (35%) and artificial surfaces (23%) within 2 miles, grassland (56%) and trees (33%) within 10 miles, and grassland (54%) and water (22%) within 50 miles.

2 miles
600 ft
10 miles
2,549 ft
50 miles
4,698 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
Nearby: Paso Robles 9.3 mi · San Luis Obispo 14 mi · Arroyo Grande 26 mi · Nipomo 33 mi · Santa Maria 39 mi · Orcutt 45 mi · Coalinga 48 mi · Lompoc 60 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Atascadero (35.4894°, -120.6707°, elevation 879 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).