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

Weather in Longmont, Colorado

High country wildflowers peak. Day 59 of spring. Read this microseason across nine climate regions →

Longmont, CO
Sunday, May 17 at 1:04 AM
76
°
Partly Cloudy
Feels like
70°
Humidity
24%
Wind
7 mph
Sunrise
5:43 AM
Sunset
8:10 PM
Longmont, CO
Hour by hour · 24h
83°
7p
79°
8p
74°
9p
72°
10p
67°
11p
62°
12a
61°
1a
60°
2a
57°
3a
55°
4a
53°
5a
51°
6a
54°
7a
62°
8a
71°
9a
74°
10a
77°
11a
81°
12p
82°
1p
83°
2p
84°
3p
84°
4p
84°
5p
82°
6p
L 51°H 84°
Longmont, CO
7-day forecast
  1. Today
    May 16
    Overcast
    19%
    77°57°
  2. Sunday
    May 17
    Rain
    44%
    71°51°
  3. Monday
    May 18
    Light Snow Shwrs
    100%
    50°33°
  4. Tuesday
    May 19
    Drizzle
    70%
    53°30°
  5. Wednesday
    May 20
    Overcast
    70%
    69°37°
  6. Thursday
    May 21
    Drizzle
    40%
    61°46°
  7. Friday
    May 22
    Overcast
    28%
    72°41°
Longmont, CO
Anemometer · 24h winds · from true
NESW
From · True
SSE
165° · veering 152°
Direction
SSE
165°
Sustained
7
mph
Gust
12
mph
Peak 24h
31
avg 8
Beaufort · 2 · LIGHT BRZ
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 8 · pk 31 @ 1:00a
−24h−18h−12h−6hnow
Light breeze veering 152° from the sse.
Longmont, CO
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
838.0
+2.5 mb in 3h · steady · 24.75 inHg
Now
838.0
mb
3h
+2.5
mb
12h
-6.9
mb
24h
-1.5
mb
Regime · STORM
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 835846
−24h−18h−12h−6hnow
Deep low — expect rough seas, strong wind, and persistent rain.
Longmont, CO
Air quality
90
AQI
Moderate
PM 2.5
6.2 μg/m³
PM 10
8.5 μg/m³
NO₂
6.9 μg/m³
Ozone
114.0 μg/m³
UV Index
0.2 Low
Longmont, CO
Almanac · Sunday, May 17
When the dew is on the grass, rain will never come to pass.
Civil dawn
11:14 AM
Sunrise
5:43 AM
Daylight
14h 27m
Sunset
8:10 PM
Civil dusk
2:41 AM
Planting note
Direct sow okra, melons, and southern peas. Thin carrot rows.
Longmont, CO
The moon
New Moon
0% illuminated
Moonrise
11:51 AM
Moonset
2:43 AM
In sign
♉︎ Taurus
Longmont, CO
Microseason · 28 of 72
May 16–20

High country wildflowers peak

bird
Jan 137% of the yearDec 31

Read this microseason across nine climate regions →

Longmont at a glance

  • Today vs. normal: 5°F above the seasonal normal for this latitude
  • Last frost: April 17 (climatological average for this latitude)
  • Microseason: 28 of 72, May 16–20
  • Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.

Right now in the garden

Warm-season window is open

As of May 17, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.

ZIP codes in Longmont

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.