US Post Office and Federal Building-Delta Main · Photo: Jeffrey Beall from Colorado, USA · CC BY-SA 2.0Few U.S. towns get less rain and snow than Delta: 9 inches a year
On a normal January night the air cools to about 17°. Its July heat outdoes that of 90% of U.S. towns. Compared with 1901–2000, the average now sits 2.4° higher. The outdoor season, with highs of 76–82°, runs through May and September.
A year in Delta at a glance
Each month’s typical high and low, and what it brings.
What stands out about Delta’s climate
Compared with towns across the U.S., with Delta’s place in Colorado beside it.
What a year in Delta feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 159 frost-free days a year
In half of years the last 32° night comes by May 1 and the first by October 7. Frost and day counts come from NOAA’s station at Delta 3e, CO, 3 miles from the town’s center, at about the same height.
The 2023 USDA map puts Delta’s center in zone 6b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −3°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 22 inches of snow a winter
Snow, measured at Montrose #2, CO, falls mostly in December. Precipitation (rain plus melted snow) adds up to 9 inches a year; September is the wettest month and June the driest. Rain or snow falls on about 65 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Delta
87% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Delta 3e, CO.
Living with Delta’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
159 frost-free days in zone 6b. The last frost comes by May 1 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 7.
Months with highs of 62–84° and lows of 40° or more: May and September. 11 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Delta from natural hazards, river flooding is the largest share (63%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Delta and similar climates
TownRatings has no climate map of the towns around Delta yet.
Climates most like Delta’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 |
|---|---|---|---|---|
| Delta, CO | 17° | 93° | 9" | 22" |
| Eagle Mountain, UT | 18° | 91° | 10" | 26" |
| Winnemucca, NV | 21° | 93° | 8" | 22" |
| North Valley, NM | 21° | 93° | 10" | 12" |
| Jerome, ID | 21° | 90° | 10" | 24" |
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 Delta averaged 2.4° warmer than the 1900s. The biggest change is in January (+4.3°).
A bigger shift than in all but 113 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 Delta compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Delta’s place among Colorado’s.
Delta weather by month
Highs, lows and precipitation from NOAA’s grid at Delta’s center; snow, wet days and snow on the ground from Montrose #2, CO. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 41° | 17° | 0.6" | 4.7" | 5 | 16 | 20° – 36° |
| February | 48° | 23° | 0.5" | 3.9" | 5 | 6 | 31° – 41° |
| March | 59° | 31° | 0.7" | 2.2" | 5 | 2 | 40° – 50° |
| April | 66° | 36° | 0.7" | 0.6" | 6 | 0 | 46° – 57° |
| May | 76° | 45° | 0.8" | 0.0" | 6 | 0 | 55° – 65° |
| June | 88° | 53° | 0.5" | 0.0" | 3 | 0 | 65° – 75° |
| July | 93° | 59° | 1.0" | 0.0" | 6 | 0 | 72° – 81° |
| August | 90° | 58° | 1.0" | 0.0" | 8 | 0 | 70° – 79° |
| September | 82° | 49° | 1.3" | 0.0" | 7 | 0 | 60° – 69° |
| October | 68° | 37° | 1.0" | 0.5" | 6 | 1 | 47° – 58° |
| November | 53° | 27° | 0.6" | 2.7" | 4 | 2 | 33° – 48° |
| December | 41° | 18° | 0.5" | 6.9" | 5 | 11 | 24° – 36° |
| Year | 67° | 38° | 8.9" | 21.5" | 65 | 36 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from 20° to 36°. August is the most reliable, staying within 9°.
Where Delta’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 Delta’s center.
- Snow: Montrose #2, CO.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Delta 3e, CO, 3 miles from the town’s center, at about the same height; 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 Delta’s climate
What is the weather like in Delta?
A typical July afternoon reaches 93°, a January night drops to 17°, and about 22 inches of snow falls in a normal winter. Colder January nights than 73% of U.S. towns; hotter July afternoons than 90% of U.S. towns.
How cold does it get in Delta in winter?
January nights average 17°. About 160 nights a year reach 32° or below and 4 reach 0° or below. In the coldest January of the last 30 years the month averaged 20°.
How much snow does Delta get?
About 22 inches in a normal winter at Montrose #2, CO, most of it in December, with snow on the ground about 36 days a year.
How hot does it get in Delta?
July, with a typical high of 93° and a low of 59°. About 68 days a year reach 90° and 5 reach 100° (Delta 3e, CO).
When is the first and last frost in Delta?
In half of years the last spring frost (32°) comes by May 1 and the first fall frost by October 7, about 159 frost-free days, at Delta 3e, CO.
What growing zone is Delta in?
Zone 6b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −3°.
What is the best time of year to visit Delta?
By one simple rule (highs of 62–84° and lows of 40° or more), May and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Delta getting warmer?
Yes: 1991–2020 averaged 2.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than all but 113 U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Delta.
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.