Harper, Texas climate: Normal weather by month, frost dates and records
Harper's normal year runs from 34°F January nights to 93°F August afternoons, with 28.3 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 18.2°C, January lows of 1°C, August highs of 34°C, 718 mm of precipitation a year.
- NOAA stationHarper (3 mi ENE)
- Station IDUSC00413954
- Location30.31°N 99.20°W
- Elevation2,110 ft (643 m)
- Population (census place)1,199
On October 23, the normal high in Harper is 76°F and the normal low 51°F, and the chance of measurable rain or snow is 19%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Harper.
- Jan 60° 34°
- Feb 64° 38°
- Mar 70° 45°
- Apr 77° 52°
- May 83° 61°
- Jun 89° 67°
- Jul 92° 69°
- Aug 93° 68°
- Sep 87° 62°
- Oct 79° 54°
- Nov 68° 44°
- Dec 61° 37°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Harper each month?
August is the warmest month, with normal highs of 93°F; January the coldest, with normal lows of 34°F. The most precipitation falls in May (4.15 in), the least in January (1.46 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 60°F | 34°F | 47.3°F | 1.46 | 5 | <1 | 12 | 10 h 20 min |
| February | 64°F | 38°F | 50.9°F | 1.66 | 5 | <1 | 8 | 11 h 10 min |
| March | 70°F | 45°F | 57.3°F | 2.58 | 7 | <1 | 4 | 12 h |
| April | 77°F | 52°F | 64.7°F | 2.10 | 5 | 2 | 1 | 12 h 50 min |
| May | 83°F | 61°F | 72.1°F | 4.15 | 7 | 5 | <1 | 13 h 40 min |
| June | 89°F | 67°F | 78.0°F | 2.80 | 6 | 15 | <1 | 14 h 10 min |
| July | 92°F | 69°F | 80.5°F | 1.74 | 4 | 25 | <1 | 14 h |
| August | 93°F | 68°F | 80.7°F | 2.14 | 4 | 27 | <1 | 13 h 20 min |
| September | 87°F | 62°F | 74.5°F | 3.18 | 6 | 11 | <1 | 12 h 20 min |
| October | 79°F | 54°F | 66.2°F | 2.72 | 6 | 1 | 1 | 11 h 30 min |
| November | 68°F | 44°F | 56.0°F | 2.14 | 5 | <1 | 4 | 10 h 40 min |
| December | 61°F | 37°F | 48.9°F | 1.61 | 5 | <1 | 11 | 10 h 10 min |
| Year (annual) | 77°F | 53°F | 64.7°F | 28.28 | 65 | 86 | 41 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 16°C | 1°C | 8.5°C | 37 mm |
| February | 18°C | 3°C | 10.5°C | 42 mm |
| March | 21°C | 7°C | 14.1°C | 66 mm |
| April | 25°C | 11°C | 18.2°C | 53 mm |
| May | 28°C | 16°C | 22.3°C | 105 mm |
| June | 32°C | 19°C | 25.6°C | 71 mm |
| July | 33°C | 21°C | 26.9°C | 44 mm |
| August | 34°C | 20°C | 27.1°C | 54 mm |
| September | 30°C | 17°C | 23.6°C | 81 mm |
| October | 26°C | 12°C | 19.0°C | 69 mm |
| November | 20°C | 7°C | 13.3°C | 54 mm |
| December | 16°C | 3°C | 9.4°C | 41 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00413954; 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.
When is the best weather to visit Harper?
Normal highs sit between 65°F and 85°F in March, April, May, October and November. Of those, April has the fewest days with rain (5).
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 USC00413954.
When is the last frost in Harper?
In Harper, the last spring frost (32°F) comes after March 15 in half of years and after April 12 in one year in ten; the first autumn frost comes before November 15 in half of years and before October 27 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
- March 151 year in 10 after April 12; 9 in 10 after February 24
- First autumn frost, half of years before
- November 151 year in 10 before October 27; 9 in 10 before December 6
NOAA puts the median frost-free season at 243 days, and the season without a hard freeze (28°F) at 270 days.
A hard freeze (28°F) comes after March 2 in half of springs and before November 29 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Harper in zone 8a in ZIP code 78631.
Frost dates for every NOAA station in Texas · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00413954; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 in Harper?
In a normal year in Harper, 86 days a year reach 90°F (4 of them 100°F or more), 41 nights fall to 32°F or colder and 65 days bring measurable precipitation.
- Days at 90°F or more
- 86a normal year
- Days at 100°F or more
- 4a normal year
- Nights at 32°F or colder
- 41a normal year
- Days that stay below freezing
- 2high of 32°F or less
- Days with 0.01 inch of precipitation
- 65a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00413954.
How sunny is Harper?
Over a year 81% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Harper, 5.0 kWh per square metre a day. August is the sunniest month (87%) and February the cloudiest (75%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 77% | 3.3 |
| February | 75% | 4.0 |
| March | 75% | 4.9 |
| April | 78% | 5.8 |
| May | 78% | 6.1 |
| June | 86% | 7.0 |
| July | 86% | 6.8 |
| August | 87% | 6.4 |
| September | 81% | 5.3 |
| October | 82% | 4.5 |
| November | 79% | 3.4 |
| December | 77% | 3.0 |
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 much heating and cooling does Harper need?
A normal year in Harper brings 2,208 heating degree days, 59% fewer than the median U.S. place (5,373), and 2,139 cooling degree days, 2.4 times the median (908). Three months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 5,899 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 551 | 1 |
| February | 400 | 5 |
| March | 259 | 21 |
| April | 93 | 84 |
| May | 18 | 237 |
| June | 0 | 390 |
| July | 0 | 479 |
| August | 0 | 486 |
| September | 5 | 290 |
| October | 85 | 122 |
| November | 293 | 22 |
| December | 502 | 2 |
| Year (annual) | 2,208 | 2,139 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00413954. 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.
Has Harper been warmer than normal lately?
2025 averaged 67.2°F, 2.5°F above the 1991-2020 normal of 64.7°F. 4 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 65.4°F | +0.7°F | 26.39 |
| 2022 | 66.2°F | +1.5°F | 17.12 |
| 2024 | 68.2°F | +3.5°F | 24.88 |
| 2025 | 67.2°F | +2.5°F | 33.12 |
Source: observed years: ACIS, station USC00413954. A year counts only with all twelve months complete.
How does Harper's climate compare?
Harper is warmer than 116 of the other 320 places with their own NOAA record in Texas, and wetter than 137. Across the 7,247 U.S. stations with normals, its annual mean of 64.7°F is warmer than 87%.
In the Köppen classification computed from these normals, Harper is Cfa: temperate, 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.
Questions about Harper's climate
What is the coldest month in Harper?
January, with a normal high of 60°F and a normal low of 34°F. The warmest is August (93°F by day, 68°F at night).
Does it snow in Harper?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month in Harper?
May, with 4.15 in of precipitation in a normal year; the driest is January with 1.46 in.
What plant hardiness zone is Harper in?
The USDA's 2023 map puts Harper in zone 8a in ZIP code 78631.
How late can frost come in Harper?
In half of years the last 32°F night comes after March 15; in one year in ten it comes after April 12. Waiting until April 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Texas climateThe statewide normals and every place in the state
- Kerrville, TX17 miles from this station, 64.6°F a year
- Fredericksburg, TX18 miles from this station, 65.5°F a year
- Hunt (10 mi W), TX25 miles from this station, 63.9°F a year
- Mason, TX30 miles from this station, 66.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made