Wester Ogle · Photo: Pubdog at en.wikipedia · Public domainWet weather: 48 inches of rain and melted snow a year in Garrison, more than in 76% of U.S. towns
High summer brings afternoon highs near 87°. By July afternoons alone, it runs hotter than 62% of U.S. towns. Since 1901–2000, the year has warmed by 1.9°, most of all in December. Central heating does most of its work from November to March, in months below 50° on average.
A year in Garrison at a glance
Each month’s typical high and low, and what it brings.
What stands out about Garrison’s climate
Compared with towns across the U.S., with Garrison’s place in Maryland beside it.
What a year in Garrison feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 220 frost-free days a year
In half of years the last 32° night comes by April 2 and the first by November 7. Frost and day counts come from NOAA’s station at Cylburn, MD, 6 miles from the town’s center, 250 ft lower.
The 2023 USDA map puts Garrison’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 5°. 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 19 inches of snow a winter
Snow, measured at Baltimore Wash International Airport, falls mostly in February. Precipitation (rain plus melted snow) adds up to 48 inches a year; September is the wettest month and February the driest. Rain or snow falls on about 121 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Garrison
78% of the work is heating. Months averaging under 55° run from November 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 Cylburn, MD.
Living with Garrison’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
220 frost-free days in zone 7a. The last frost comes by Apr 2 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 7.
Months with highs of 62–84° and lows of 40° or more: April, May, June, September and October. 0.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Garrison from natural hazards, river flooding is the largest share (50%); heat waves, cold waves, winter storms and ice storms together are 27%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Garrison and its neighbors
Every town next door is within a degree of Garrison in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Garrison’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 |
|---|---|---|---|---|
| Garrison, MD | 24° | 87° | 48" | 19" |
| Colonia, NJ | 24° | 87° | 48" | 21" |
| Cynthiana, KY | 24° | 87° | 48" | 16" |
| Milford, OH | 23° | 87° | 45" | 16" |
| North Vernon, IN | 23° | 86° | 48" | 17" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Garrison averaged 1.9° warmer than the 1900s. The biggest change is in December (+3.0°).
A bigger shift than in 86% 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 Garrison compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Garrison’s place among Maryland’s.
Garrison weather by month
Highs, lows and precipitation from NOAA’s grid at Garrison’s center; snow, wet days and snow on the ground from Baltimore Wash International Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 41° | 24° | 3.2" | 6.4" | 10 | 4 | 24° – 40° |
| February | 45° | 25° | 2.9" | 7.5" | 9 | 5 | 24° – 43° |
| March | 53° | 32° | 4.0" | 2.8" | 11 | 2 | 37° – 52° |
| April | 66° | 42° | 3.8" | 0.0" | 11 | 0 | 50° – 59° |
| May | 75° | 52° | 4.4" | 0.0" | 12 | 0 | 59° – 69° |
| June | 83° | 61° | 4.4" | 0.0" | 11 | 0 | 68° – 76° |
| July | 87° | 66° | 4.6" | 0.0" | 10 | 0 | 71° – 80° |
| August | 85° | 64° | 4.2" | 0.0" | 10 | 0 | 70° – 77° |
| September | 78° | 57° | 4.7" | 0.0" | 9 | 0 | 64° – 71° |
| October | 67° | 45° | 4.4" | 0.0" | 9 | 0 | 53° – 62° |
| November | 55° | 35° | 3.7" | 0.1" | 9 | 0 | 39° – 50° |
| December | 46° | 28° | 3.8" | 2.5" | 10 | 2 | 28° – 48° |
| Year | 65° | 44° | 48.0" | 19.3" | 121 | 13 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 28° to 48°. September is the most reliable, staying within 7°.
Where Garrison’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 Garrison’s center.
- Snow: Baltimore Wash International Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Cylburn, MD, 6 miles from the town’s center, 250 ft lower; 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 Garrison’s climate
What is the weather like in Garrison?
A typical July afternoon reaches 87°, a January night drops to 24°, and about 19 inches of snow falls in a normal winter. Milder January nights than 59% of U.S. towns; hotter July afternoons than 62% of U.S. towns.
How cold does it get in Garrison in winter?
January nights average 24°. About 92 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 24°.
How much snow does Garrison get?
About 19 inches in a normal winter at Baltimore Wash International Airport, most of it in February, with snow on the ground about 13 days a year.
How hot does it get in Garrison?
July, with a typical high of 87° and a low of 66°. About 18 days a year reach 90° (Cylburn, MD).
When is the first and last frost in Garrison?
In half of years the last spring frost (32°) comes by April 2 and the first fall frost by November 7, about 220 frost-free days, at Cylburn, MD.
What growing zone is Garrison in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 5°.
What is the best time of year to visit Garrison?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, June, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Garrison getting warmer?
Yes: 1991–2020 averaged 1.9° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 86% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Garrison.
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.