Photo: Billy Hathorn · CC BY-SA 3.0Granby gets about 81 inches of snow a winter, more than 95% of U.S. towns
High summer brings afternoon highs near 78°. The gap between a January night and a July afternoon is 76°. Summers stay cool: July afternoons here are cooler than in 96% of U.S. towns. The heating season runs October to May: each of those months averages under 50°.
A year in Granby at a glance
Each month’s typical high and low, and what it brings.
What stands out about Granby’s climate
Compared with towns across the U.S., with Granby’s place in Colorado beside it.
What a year in Granby feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 84 frost-free days a year
In half of years the last 32° night comes by June 13 and the first by September 7. Frost and day counts come from NOAA’s station at Grand Lake 6 Ssw, CO, 9 miles from the town’s center, 120 ft higher.
The 2023 USDA map puts Granby’s center in zone 4a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −26°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 81 inches of snow a winter
Snow, measured at Williams Fork Dam, CO, falls mostly in January, February and December. Precipitation (rain plus melted snow) adds up to 17 inches a year; April is the wettest month and November the driest. Rain or snow falls on about 107 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Granby
Nearly all of the work is heating: a normal year has almost no cooling days. Months averaging under 55° run from September through June.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Grand Lake 6 Ssw, CO.
Living with Granby’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
84 frost-free days in zone 4a. The last frost comes by Jun 13 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 7.
Months with highs of 62–84° and lows of 40° or more: July and August. 65 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Granby from natural hazards, avalanches are the largest share (60%). Normals are averages; the hazards page covers the extremes.
Natural hazards →Granby and similar climates
TownRatings has no climate map of the towns around Granby yet.
Climates most like Granby’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Granby, CO | 3° | 78° | 17" | 81" |
| Jackson, WY | 6° | 80° | 19" | 78" |
| Minot, ND | 2° | 82° | 17" | 52" |
| Thief River Falls, MN | −4° | 79° | 22" | 50" |
| Kingsford, MI | 5° | 80° | 29" | 61" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Granby averaged 1.3° warmer than the 1900s. The biggest change is in March (+2.8°).
A smaller shift than in 55% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Granby compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Granby’s place among Colorado’s.
Granby weather by month
Highs, lows and precipitation from NOAA’s grid at Granby’s center; snow, wet days and snow on the ground from Williams Fork Dam, CO. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 30° | 3° | 1.3" | 14.2" | 10 | 31 | 11° – 23° |
| February | 34° | 5° | 1.2" | 13.6" | 10 | 29 | 14° – 27° |
| March | 43° | 14° | 1.3" | 10.4" | 8 | 27 | 23° – 35° |
| April | 51° | 22° | 1.9" | 11.9" | 10 | 10 | 32° – 42° |
| May | 62° | 30° | 1.8" | 2.7" | 10 | 1 | 42° – 49° |
| June | 72° | 37° | 1.3" | 0.1" | 7 | 0 | 51° – 59° |
| July | 78° | 42° | 1.5" | 0.0" | 9 | 0 | 57° – 64° |
| August | 76° | 41° | 1.7" | 0.0" | 10 | 0 | 55° – 62° |
| September | 69° | 33° | 1.6" | 0.3" | 8 | 0 | 46° – 55° |
| October | 56° | 24° | 1.4" | 4.8" | 8 | 3 | 34° – 45° |
| November | 42° | 14° | 1.1" | 9.9" | 8 | 15 | 20° – 36° |
| December | 31° | 5° | 1.2" | 13.3" | 9 | 28 | 13° – 24° |
| Year | 54° | 22° | 17.1" | 81.2" | 107 | 144 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 20° to 36°. August is the most reliable, staying within 7°.
Where Granby’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Granby’s center.
- Snow: Williams Fork Dam, CO.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Grand Lake 6 Ssw, CO, 9 miles from the town’s center, 120 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Granby’s climate
What is the weather like in Granby?
A typical July afternoon reaches 78°, a January night drops to 3°, and about 81 inches of snow falls in a normal winter. Colder January nights than all but 93 U.S. towns; cooler July afternoons than 96% of U.S. towns.
How cold does it get in Granby in winter?
January nights average 3°. About 245 nights a year reach 32° or below and 44 reach 0° or below. In the coldest January of the last 30 years the month averaged 11°.
How much snow does Granby get?
About 81 inches in a normal winter at Williams Fork Dam, CO, most of it in January, February and December, with snow on the ground about 144 days a year.
How hot does it get in Granby?
July, with a typical high of 78°. 90° days are rare: none in a normal year at Grand Lake 6 Ssw, CO.
When is the first and last frost in Granby?
In half of years the last spring frost (32°) comes by June 13 and the first fall frost by September 7, about 84 frost-free days, at Grand Lake 6 Ssw, CO.
What growing zone is Granby in?
Zone 4a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −26°.
What is the best time of year to visit Granby?
By one simple rule (highs of 62–84° and lows of 40° or more), July and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Granby getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 55% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Granby.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.