Weather StoryAlmanac, microseasons, and the day's weather story.

Granby, Colorado Weather

Monsoon storms drench the south. Day 15 of summer. Read this microseason across nine climate regions →

Granby weather forecast — hour by hour, 7-day outlook, NOAA radar

Granby, CO
Sunday, July 5 at 6:55 AM
47
°
Clear
Feels like
42°
Humidity
50%
Wind
2 mph
Sunrise
11:40 PM
Sunset
2:35 PM
Granby, CO
Hour by hour · 24h
24-Hour ForecastGranby, CO: 24-hour forecast. Temperatures range from 44 to 82 degrees Fahrenheit.
L 44°H 82°
Granby, CO
7-day forecast
  1. Today
    Jul 5
    Overcast
    —
    —
    82°44°—
  2. Monday
    Jul 6
    Overcast
    —
    —
    85°57°+3°
  3. Tuesday
    Jul 7
    Light Rain
    55%
    0.09″
    86°52°+1°
  4. Wednesday
    Jul 8
    Overcast
    46%
    —
    85°51°-1°
  5. Thursday
    Jul 9
    Light Drizzle
    39%
    0.01″
    83°51°-2°
  6. Friday
    Jul 10
    Overcast
    14%
    —
    87°51°+4°
  7. Saturday
    Jul 11
    Overcast
    —
    —
    92°51°+5°
Granby, CO
Next 24 hours · Cold now
HOT 90°35°63°90°12a6a12p6pnow 44°high 82°low 44°
Granby, CO
Anemometer · 24h winds · from true
NESW
From · True
SSW
198° · veering 81°
Direction
SSW
198°
Sustained
2
mph
Gust
3
mph
Peak 24h
12
avg 4
Beaufort · 1 · LIGHT AIR
0
CALM
<1
1
LIGHT AIR
1–3
2
LIGHT BRZ
4–7
3
GENTLE BRZ
8–12
4
MOD BRZ
13–18
5
FRESH BRZ
19–24
6
STRONG BRZ
25–31
7
NEAR GALE
32–38
24h · sust vs gust · mph
avg 4 · pk 12 @ 1:00p
01020MPHB1B2B3B4B5-21h-18h-15h-12h-9h-6h-3h-24hNOWpk 192SUSTGUST
−24h−18h−12h−6hnow
A whisper of wind — leaves barely shift on the trees.
Granby, CO
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
760.9
-1.5 mb in 3h · falling · 22.47 inHg
Now
760.9
mb
3h
-1.5
mb
12h
-7.3
mb
24h
-2.4
mb
Regime · STORM
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 759–770
755760765770775-21h-18h-15h-12h-9h-6h-3h-24hNOW769.5759.4759.6
−24h−18h−12h−6hnow
Deep low still deepening — rough seas, strong wind, persistent rain.
Granby, CO
Air quality
40
AQI
Good
↓-15 in 6h▲Peak ~62 @ 7 PM

AQI 40 (Good), driven by PM2.5. AQI down 15 over the last 6 hours — air quality is improving sharply. PM2.5 at 8.6 µg/m³ (AQI 48) with a 0.70 fine-to-coarse ratio and 2 mph wind — combustion smoke trapped in calm air, not road dust.

OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 7 PM.

PM 2.5DRIVERGood
8.6μg/m³
PM 10Good
12μg/m³
NO₂Good
6μg/m³
OzoneModerate
75μg/m³
UV IndexLow
0.1

What's driving it

Ozone × UV × Sky

Ozone at AQI 35 now. With UV 0.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 8 around 1 PM.

Present
AQI 35
UV peak
0.3 at 1 PM
Sky at peak
clear
Projected peak
AQI 8

PM × Wind × Precip

PM2.5 at 8.6 µg/m³ (AQI 48) with a 0.70 fine-to-coarse ratio and 2 mph wind — combustion smoke trapped in calm air, not road dust.

PM2.5/PM10
0.70
Wind
calm
Recent rain
0h in last 6h
Pattern
stagnant smoke

Trends

Seven days of AQI and PM2.5.

Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).

7-DAY AQI TREND50100SUNMONTUEWEDTHUFRISATSUN7-DAY PM2.5 TREND · μg/m³300
Granby, CO
Sky cover · visibility · 24h
Cloud cover
0%
CLEAR
100%0%−24h−18h−12h−6hnow
Visibility
76.9mi
UNLIMITED
185 mi0 mi−24h−18h−12h−6hnow
Earth · GOES-19 ABI
Full Disk · Visible · GeoColor
GOES-19 full disk Visible · GeoColor
True-color daytime, blue/IR sandwich at night
12:55 UTC · Granby, CO · NOAA NESDIS / STAR · up to 10848 px
Continental US · GOES-19 ABI
CONUS Sector · Visible · GeoColor
GOES-19 CONUS Visible · GeoColor
Daytime true-color, blue-light/IR sandwich at night
12:55 UTC · Granby, CO · NOAA NESDIS / STAR · 5-min cadence · up to 10000 px
Granby, CO
Satellite · infrared · animated
Granby, CO
Loading IR frames…
IR · cloud-top temp© RainViewer · Carto
Granby, CO
Almanac · Sunday, July 5
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
Civil dawn
5:09 AM
Sunrise
11:40 PM
Daylight
14h 55m
Sunset
2:35 PM
Civil dusk
9:09 PM
Planting note
Harvest early potatoes. Begin drying onions on the surface.
Granby, CO
The moon
Waning Gibbous
73% illuminated
Moonrise
11:23 PM
Moonset
11:18 AM
In sign
♓︎ Pisces
Granby, CO
Microseason
Jul 1–5

Monsoon storms drench the south

insect
Jan 151% of the yearDec 31

Read this microseason across nine climate regions →

Granby at a glance

  • Today vs. normal: 25°F below the seasonal normal for this latitude
  • Last frost: April 16 (climatological average for this latitude)
  • Microseason: Jul 1–5
  • Planting window: Harvest early potatoes. Begin drying onions on the surface.

ZIP code: 80446

16-Day Forecast — Granby

  1. Sun82°46°2%
  2. Mon85°57°4%
  3. Tue86°52°55%
  4. Wed85°51°46%
  5. Thu83°51°39%
  6. Fri87°51°14%
  7. Sat92°51°2%
  8. Sun95°55°3%
  9. Mon98°57°14%
  10. Tue96°56°24%
  11. Wed97°58°37%
  12. Thu96°53°49%
  13. Fri97°52°42%
  14. Sat86°56°42%
  15. Sun89°54°35%
  16. Mon91°55°49%

Forecast data from Open-Meteo (CC BY 4.0).

Right now in the garden

Peak growing season

As of July 5, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.

SPC Convective Outlook

Storm Prediction Center — Granby

SPC includes Granby in the general thunderstorm area today — no severe risk, but storms are possible.

  • TODAYTSTMGeneral Thunderstorms
  • TOMORROWTSTMGeneral Thunderstorms
  • DAY 3TSTMGeneral Thunderstorms

Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.

Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.

January 1–5: Deep freeze grips the high peaks.January 6–10: Ice thickens on alpine tarns.January 11–15: Springs stir beneath locked earth.January 16–20: Grouse call from the transition zone.January 21–25: First signals of the soil's turning.January 26–31: Stream water crystallizes thick.February 1–5: The year's coldest fortnight begins.February 6–10: East wind carries a subtle promise.February 11–15: Snowmelt springs whisper beneath ice.February 16–20: Red-wing calls rise from the wetlands.February 21–25: Rain begins to trace the snowline upward.February 26–28: Mist gathers in the warming canyons.March 1–5: Grass and trees stir from their sleep.March 6–10: Hibernators break through frozen ground.March 11–15: First blooms open to the spring sun.March 16–20: Mountain bluebirds return to the summits.March 21–25: Spring equinox at the divide.March 26–31: Aspen catkins burst in clusters.April 1–5: Thunderstorms rumble over granite peaks.April 6–10: Swallows and swifts slice the warming sky.April 11–15: Sandhill cranes call through the wetlands.April 16–20: Rainbows arch over the snowfields.April 21–25: New growth explodes across the montane.April 26–30: Last frost yields to summer growth.May 1–5: Wildflowers crest the high meadows.May 6–10: Summer monsoon clouds gather southward.May 11–15: Snowmelt crests toward the divide.May 16–20: High country wildflowers peak.May 21–25: Summer heat accelerates the growing season.May 26–31: Summer settles into the high country.June 1–5: Pikas hayfeeding in granite peaks.June 6–10: Glacier lily carpets the snowmelt.June 11–15: Paintbrush crowns the ridges.June 16–20: Thunderheads build by noon.June 21–25: Long light holds the peaks.June 26–30: Monsoon moisture drifts north.July 1–5: Monsoon storms drench the south.July 6–10: Wind builds through canyons.July 11–15: Lightning crowns every peak.July 16–20: Elk herds claim alpine meadows.July 21–25: Pika caches reach their peak.July 26–31: Monsoon pulses weaken northward.August 1–5: Summer heat breaks with monsoon.August 6–10: First frost creeps to peaks.August 11–15: Cool wind returns from north.August 16–20: Monsoon clouds gather over the peaks.August 21–25: The monsoon breaks into scattered showers.August 26–31: Summer insects thin as autumn wind rises.September 1–5: Elk descend from summer high meadows.September 6–10: Dew crystallizes on high grass at dawn.September 11–15: Hawks begin the long crossing southward.September 16–20: Equinox: darkness claims the high passes.September 21–25: Thunder retreats as the monsoon dies.September 26–30: First frost hardens the high valleys.October 1–5: October: the aspen stands reach their peak.October 6–10: Aspen gold slides downslope with the chill.October 11–15: Snow settles on the high passes.October 16–20: Elk bugling fades as rut nears its end.October 21–25: First hard frost grips the basin.October 26–31: Late rains settle into November patterns.November 1–5: Aspen canopy falls to earth.November 6–10: Granite bones emerge from cover.November 11–15: Earth begins to harden.November 16–20: Bare ranges hold silence.November 21–25: Snow returns to the peaks.November 26–30: North wind strips the landscape.December 1–5: Deep darkness settles over the ranges.December 6–10: Winter locks the high country.December 11–15: Elk withdraw to winter range.December 16–20: Ice thickens across frozen water.December 21–25: Winter solstice — the sun returns.December 26–31: The year closes in silence.🌱February 14 — First skunk-cabbage spathes thaw their way up☀️March 20 — Spring equinox — day and night balance🌸April 5 — Cherry blossoms peak in the parks🐦May 10 — Warbler migration peaks along the coast✨May 25 — First fireflies scout the meadows at dusk🌞June 21 — Summer solstice — longest day🦗July 25 — Peak cicada chorus in the afternoons🌊August 18 — Warmest sea-surface temperatures of the year🍂September 22 — Autumn equinox — the slow turn❄️October 25 — First widespread frost in the suburbs🍁November 10 — Peak leaf color across the Hudson Valley🌙December 21 — Winter solstice — longest night

Microseason · July 1–5

Monsoon storms drench the south

Monsoon established in southern Mountain West (New Mexico, southern Utah, Arizona north); afternoon downpours and lightning common.

Day 186 of 365 · Wedge 37 of 72

The solar year drawn as a wheel of 72 five-day windows. Each wedge is one microseason; the four colored arcs mark winter, spring, summer, and autumn; the small icons sit at notable phenological events. The crimson pointer creeps clockwise as the year turns.

Planting calendar

MonthPlantHarvest
January——
February——
March——
Aprillettuce, peas, spinach, radishes—
Maylettuce, peas, spinach, radishes, tomatoes, peppers, beans, squashlettuce, peas, radishes
Junetomatoes, peppers, beans, squashlettuce, peas, radishes
Julytomatoes, peppers, beans, squashtomatoes, beans, summer squash
August—tomatoes, beans, summer squash
Septemberfall brassicas, garlic (overwinter), carrotstomatoes, beans, summer squash
Octoberfall brassicas, garlic (overwinter), carrotswinter squash, tomatoes (last)
November——
December——

A year in weather

The year in Granby tops out in July (~59°F) and dips lowest in January (~14°F), with August wettest at 1.7 inches and March driest at 0.7 inches.

MonthMean tempPrecipRainy days
January14°0.9″3
February18°0.8″3
March27°0.7″3
April36°1.2″4
May45°1.6″5
June54°1.2″4
July59°1.6″5
August58°1.7″6
September51°1.5″4
October41°1.1″4
November29°0.7″3
December18°0.8″3

Regional context

By the nearest station's NOAA NCEI 1991-2020 normals, Granby sees 14°F Januarys and 59°F Julys, a 45°F range, plus around 13.8 inches of precipitation across 45 days.

Precipitation in Granby runs summer-dominant: August averages 1.7 inches across 5.5 days of warm-season storms, while March drops to 0.7 inches over 2.6 rainy days of drier cool air. That puts Granby in a summer-convective cohort with places like Tabernash, CO, Hot Sulphur Springs, CO and Fraser, CO.

By mid-April the frosts ease in Granby, opening the season for kale, peas, spinach, and parsnips. Warm-soil crops in Granby wait about two weeks past Granby's last frost, once the soil warms. Granby's window closes around mid-November as overnight lows return below freezing. Within Granby, cold-air pooling chills low spots by 5-10°F, shifting Granby's local frost dates.

Similar climates: Tabernash, CO, Hot Sulphur Springs, CO, Fraser, CO, Parshall, CO, Grand Lake, CO.

Frequently asked

When does it freeze in Granby?
Frost typically leaves Granby by mid-April and returns to Granby near mid-November.
What is the rainy season in Granby?
August is the wettest month in Granby, about 1.7 inches on average; the year totals roughly 14 inches.
What is the warmest month in Granby?
On average July tops the year in Granby at about 59°F.
What is the coldest month in Granby?
The coldest stretch in Granby falls in January, around 14°F on average.
When can I start a vegetable garden in Granby?
Hardy spring crops go in near mid-April in Granby; tender peppers and squash wait 10–14 days.
How many rainy days does Granby get?
Granby records around 45 days of measurable precipitation annually.
What hardiness zone is Granby?
Since January in Granby averages 14°F, Granby's USDA zone follows that floor — confirm it by ZIP.
What is the 10-day forecast for Granby?
Granby's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
Will it rain this week in Granby?
See this week's day-by-day rain chances for Granby in the daily forecast above, and the next 24 hours in the hourly chart.
What is the weather like right now in Granby?
Current conditions for Granby and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
How often is the Granby forecast updated?
The Granby forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
When are sunrise and sunset in Granby?
Today's sunrise and sunset times for Granby are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
How accurate is the weather forecast for Granby?
The next few days in Granby's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.

Climate

The cold semi-arid climate of Granby, Colorado carries typical Januarys near 14°F and Julys around 59°F — 45°F of seasonal travel.

Yearly precipitation in Granby totals around 14 inches, spread over about 45 days of rain or snow.

From 40.1°N, Granby sees a 45°F seasonal swing that governs Granby's planting and frost windows.

All cities in Colorado →

Boulder, CO weather →

ZIP codes in Granby

  • 80478
  • 80446

Climate normals from the Open-Meteo Climate API. Köppen approximation from NOAA NCEI U.S. Climate Regions. See methodology for data sources, editorial rules, and corrections. Maintainer: Brian Tighe.