Waterloo, Ohio climate: Climate normals at a NOAA weather station
Waterloo's normal year runs from 20°F January nights to 86°F July afternoons, with 45.7 inches of precipitation and 14 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 11.6°C, January lows of −6°C, July highs of 30°C, 1,161 mm of precipitation a year.
- NOAA stationWaterloo
- Station IDUSC00338810
- Location38.70°N 82.47°W
- Elevation625 ft (191 m)
On October 23, the normal high in Waterloo is 65°F and the normal low 37°F, and the chance of measurable rain or snow is 33%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Waterloo.
- Jan 41° 20°
- Feb 45° 22°
- Mar 54° 29°
- Apr 67° 38°
- May 75° 49°
- Jun 83° 58°
- Jul 86° 62°
- Aug 85° 60°
- Sep 79° 52°
- Oct 68° 40°
- Nov 55° 30°
- Dec 46° 25°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Waterloo each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 20°F. The most precipitation falls in July (5.57 in), the least in November (2.94 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 41°F | 20°F | 30.7°F | 3.28 | 5.0 | 13 | <1 | 26 | 9 h 40 min |
| February | 45°F | 22°F | 33.7°F | 3.15 | 3.9 | 13 | <1 | 24 | 10 h 40 min |
| March | 54°F | 29°F | 41.7°F | 4.19 | 2.2 | 13 | <1 | 20 | 11 h 50 min |
| April | 67°F | 38°F | 52.4°F | 3.69 | 0.1 | 13 | <1 | 9 | 13 h 10 min |
| May | 75°F | 49°F | 61.8°F | 4.45 | 0.0 | 15 | 1 | 1 | 14 h 20 min |
| June | 83°F | 58°F | 70.1°F | 4.05 | 0.0 | 13 | 5 | <1 | 14 h 50 min |
| July | 86°F | 62°F | 74.0°F | 5.57 | 0.0 | 12 | 10 | <1 | 14 h 40 min |
| August | 85°F | 60°F | 72.5°F | 3.67 | 0.0 | 11 | 7 | <1 | 13 h 40 min |
| September | 79°F | 52°F | 65.6°F | 3.88 | 0.0 | 10 | 4 | <1 | 12 h 30 min |
| October | 68°F | 40°F | 53.6°F | 3.10 | 0.0 | 10 | <1 | 7 | 11 h 20 min |
| November | 55°F | 30°F | 42.6°F | 2.94 | 0.4 | 10 | <1 | 20 | 10 h 10 min |
| December | 46°F | 25°F | 35.3°F | 3.72 | 2.0 | 13 | <1 | 24 | 9 h 30 min |
| Year (annual) | 65°F | 40°F | 52.8°F | 45.69 | 13.6 | 147 | 27 | 131 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 5°C | −6°C | −0.7°C | 83 mm | 13 cm |
| February | 7°C | −5°C | 0.9°C | 80 mm | 10 cm |
| March | 12°C | −2°C | 5.4°C | 106 mm | 6 cm |
| April | 19°C | 3°C | 11.3°C | 94 mm | 0 cm |
| May | 24°C | 9°C | 16.6°C | 113 mm | 0 cm |
| June | 28°C | 14°C | 21.2°C | 103 mm | 0 cm |
| July | 30°C | 17°C | 23.3°C | 141 mm | 0 cm |
| August | 30°C | 16°C | 22.5°C | 93 mm | 0 cm |
| September | 26°C | 11°C | 18.7°C | 99 mm | 0 cm |
| October | 20°C | 4°C | 12.0°C | 79 mm | 0 cm |
| November | 13°C | −1°C | 5.9°C | 75 mm | 1 cm |
| December | 8°C | −4°C | 1.8°C | 94 mm | 5 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00338810; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Waterloo?
Normal highs sit between 65°F and 85°F in April, May, June, September and October. Of those, October has the fewest days with rain (10).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00338810.
When is the last frost at Waterloo?
In Waterloo, the last spring frost (32°F) comes after April 30 in half of years and after May 16 in one year in ten; the first autumn frost comes before October 15 in half of years and before October 3 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 301 year in 10 after May 16; 9 in 10 after April 15
- First autumn frost, half of years before
- October 151 year in 10 before October 3; 9 in 10 before October 27
NOAA puts the median frost-free season at 167 days, and the season without a hard freeze (28°F) at 189 days.
A hard freeze (28°F) comes after April 18 in half of springs and before October 25 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Waterloo in zone 7a in ZIP code 45688, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 6b: the coldest night of a typical year reaches −4°F (20 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Ohio · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00338810; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Waterloo?
In a normal year in Waterloo, 27 days a year reach 90°F, 131 nights fall to 32°F or colder and 147 days bring measurable precipitation.
- Days at 90°F or more
- 27a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 131a normal year
- Days that stay below freezing
- 18high of 32°F or less
- Days with 0.01 inch of precipitation
- 147a normal year
- Days with 1 inch of snow or more
- 6a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00338810.
How sunny is it at Waterloo?
Over a year 72% of the sunlight that would reach the ground under clear skies gets through the clouds at Waterloo, 4.0 kWh per square metre a day. August is the sunniest month (80%) and December the cloudiest (59%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 60% | 1.9 |
| February | 60% | 2.6 |
| March | 65% | 3.7 |
| April | 71% | 5.0 |
| May | 72% | 5.5 |
| June | 78% | 6.2 |
| July | 77% | 5.9 |
| August | 80% | 5.5 |
| September | 78% | 4.5 |
| October | 72% | 3.3 |
| November | 70% | 2.3 |
| December | 59% | 1.6 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Waterloo record?
A normal year at Waterloo brings 5,275 heating degree days, 2% fewer than the median U.S. place (5,373), and 873 cooling degree days, 4% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,315 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,063 | 0 |
| February | 876 | 0 |
| March | 722 | 1 |
| April | 386 | 8 |
| May | 158 | 60 |
| June | 23 | 175 |
| July | 2 | 281 |
| August | 5 | 238 |
| September | 79 | 98 |
| October | 365 | 12 |
| November | 674 | 0 |
| December | 922 | 0 |
| Year (annual) | 5,275 | 873 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00338810. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Waterloo's climate compare?
Waterloo is warmer than 75 of the 99 places with their own NOAA record in Ohio, and wetter than 86. Across the 7,247 U.S. stations with normals, its annual mean of 52.8°F is warmer than 53%.
In the Köppen classification computed from these normals, Waterloo is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Waterloo share this climate record?
Oak Hill has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Oak Hill, OH1,404 people · 15 mi N
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Waterloo's climate
What is the coldest month at Waterloo?
January, with a normal high of 41°F and a normal low of 20°F. The warmest is July (86°F by day, 62°F at night).
Does it snow at Waterloo?
Yes: 14 inches in a normal year, falling on 11 days with 0.1 inch or more, the most in January (5.0 inches).
What is the rainiest month at Waterloo?
July, with 5.57 in of precipitation in a normal year; the driest is November with 2.94 in.
What plant hardiness zone is Waterloo in?
The USDA's 2023 map puts Waterloo in zone 7a in ZIP code 45688, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −4°F (20 years, 1991-2020): zone 6b.
How late can frost come at Waterloo?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 16. Waiting until May 16 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Ohio climateThe statewide normals and every place in the state
- Hogsett R.C. Byrd Dam, WV16 miles from this station, 53.8°F a year
- Gallipolis, OH18 miles from this station, 54.9°F a year
- Ashland, KY19 miles from this station, 53.8°F a year
- South Point, OH21 miles from this station, 55.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made