Longmont, CO Weather & Growing Conditions
Overnight
60°F
Patchy Smoke
Patchy smoke and a slight chance of rain showers. Mostly cloudy. Low around 60, with temperatures rising to around 62 overnight. North northeast wind around 10 mph, with gusts as high as 16 mph. Chance of precipitation is 20%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 60°F | Patchy Smoke | 10 mph NNE | 18% |
| Tuesday | 79°F | Patchy Smoke | 6 to 9 mph ENE | 13% |
| Tuesday Night | 56°F | Patchy Smoke | 5 to 9 mph NE | 9% |
| Wednesday | 87°F | Patchy Smoke | 3 to 8 mph NE | 1% |
| Wednesday Night | 58°F | Mostly Clear | 2 to 8 mph N | 1% |
| Thursday | 96°F | Sunny | 2 to 8 mph NNW | 0% |
| Thursday Night | 61°F | Mostly Clear | 6 mph N | 1% |
| Friday | 99°F | Sunny | 1 to 7 mph S | 0% |
| Friday Night | 63°F | Mostly Clear | 6 mph SSW | 0% |
| Saturday | 100°F | Sunny | 2 to 7 mph N | 3% |
| Saturday Night | 64°F | Partly Cloudy | 3 to 7 mph WNW | 1% |
| Sunday | 99°F | Sunny | 2 to 8 mph NE | 7% |
| Sunday Night | 67°F | Partly Cloudy | 5 to 8 mph WNW | 5% |
| Monday | 98°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 3 to 10 mph N | 20% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Longmont, CO
Last spring frost
May 7
First fall frost
Oct 5
Growing season
151 days
Hardiness zone
5b
Explore more for Longmont, CO: full frost dates · planting calendar · Colorado frost dates
Climate data from the nearest NOAA station, Longmont 2 Ese, Co (1.3 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.