Helena, Oklahoma climate: Normal weather by month, frost dates and records
Helena's normal year runs from 23°F January nights to 95°F July afternoons, with 32.1 inches of precipitation and 13 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 14.9°C, January lows of −5°C, July highs of 35°C, 816 mm of precipitation a year.
- NOAA stationHelena (1 mi SSE)
- Station IDUSC00344019
- Location36.54°N 98.27°W
- Elevation1,350 ft (412 m)
- From the centerunder 1 mile
- Population1,533
On October 23, the normal high in Helena is 70°F and the normal low 44°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 Helena.
- Jan 47° 23°
- Feb 51° 27°
- Mar 61° 36°
- Apr 70° 44°
- May 80° 56°
- Jun 90° 66°
- Jul 95° 70°
- Aug 93° 69°
- Sep 85° 61°
- Oct 73° 48°
- Nov 59° 35°
- Dec 48° 26°
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 Helena each month?
July is the warmest month, with normal highs of 95°F; January the coldest, with normal lows of 23°F. The most precipitation falls in June (4.42 in), the least in January (1.04 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 47°F | 23°F | 35.1°F | 1.04 | 3.1 | 4 | <1 | 27 | 10 h |
| February | 51°F | 27°F | 38.7°F | 1.25 | 2.4 | 5 | <1 | 22 | 10 h 50 min |
| March | 61°F | 36°F | 48.2°F | 2.22 | 3.2 | 6 | <1 | 12 | 11 h 50 min |
| April | 70°F | 44°F | 57.2°F | 3.27 | 0.0 | 8 | 1 | 4 | 13 h 10 min |
| May | 80°F | 56°F | 67.6°F | 4.37 | 0.0 | 9 | 5 | <1 | 14 h 10 min |
| June | 90°F | 66°F | 77.8°F | 4.42 | 0.0 | 8 | 17 | <1 | 14 h 40 min |
| July | 95°F | 70°F | 82.7°F | 3.22 | 0.0 | 7 | 25 | <1 | 14 h 30 min |
| August | 93°F | 69°F | 80.9°F | 3.71 | 0.0 | 8 | 22 | <1 | 13 h 40 min |
| September | 85°F | 61°F | 73.0°F | 2.56 | 0.0 | 6 | 11 | <1 | 12 h 30 min |
| October | 73°F | 48°F | 60.1°F | 3.03 | 0.2 | 6 | 2 | 2 | 11 h 20 min |
| November | 59°F | 35°F | 47.1°F | 1.60 | 0.4 | 5 | <1 | 13 | 10 h 20 min |
| December | 48°F | 26°F | 37.1°F | 1.45 | 3.4 | 5 | <1 | 25 | 9 h 40 min |
| Year (annual) | 71°F | 47°F | 58.8°F | 32.14 | 12.7 | 76 | 81 | 105 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 8°C | −5°C | 1.7°C | 26 mm | 8 cm |
| February | 11°C | −3°C | 3.7°C | 32 mm | 6 cm |
| March | 16°C | 2°C | 9.0°C | 56 mm | 8 cm |
| April | 21°C | 7°C | 14.0°C | 83 mm | 0 cm |
| May | 26°C | 13°C | 19.8°C | 111 mm | 0 cm |
| June | 32°C | 19°C | 25.4°C | 112 mm | 0 cm |
| July | 35°C | 21°C | 28.2°C | 82 mm | 0 cm |
| August | 34°C | 20°C | 27.2°C | 94 mm | 0 cm |
| September | 30°C | 16°C | 22.8°C | 65 mm | 0 cm |
| October | 23°C | 9°C | 15.6°C | 77 mm | 1 cm |
| November | 15°C | 2°C | 8.4°C | 41 mm | 1 cm |
| December | 9°C | −3°C | 2.8°C | 37 mm | 9 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00344019; 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 Helena?
Normal highs sit between 65°F and 85°F in April, May and October. Of those, October has the fewest days with rain (6).
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 USC00344019.
When is the last frost in Helena?
In Helena, the last spring frost (32°F) comes after April 9 in half of years and after April 23 in one year in ten; the first autumn frost comes before October 31 in half of years and before October 18 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 91 year in 10 after April 23; 9 in 10 after March 25
- First autumn frost, half of years before
- October 311 year in 10 before October 18; 9 in 10 before November 13
NOAA puts the median frost-free season at 205 days, and the season without a hard freeze (28°F) at 225 days.
A hard freeze (28°F) comes after March 31 in half of springs and before November 8 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Helena in zone 7a in ZIP code 73741, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Helena's NOAA station is in zone 7a: the coldest night of a typical year reaches 2°F (30 complete years).
Frost dates for every NOAA station in Oklahoma · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00344019; 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 in Helena?
In a normal year in Helena, 81 days a year reach 90°F (19 of them 100°F or more), 105 nights fall to 32°F or colder and 76 days bring measurable precipitation.
- Days at 90°F or more
- 81a normal year
- Days at 100°F or more
- 19a normal year
- Nights at 32°F or colder
- 105a normal year
- Days that stay below freezing
- 13high of 32°F or less
- Days with 0.01 inch of precipitation
- 76a normal year
- Days with 1 inch of snow or more
- 5a normal year
The highest temperature in this station's record (since 1906) is 113°F, on June 25, 1911; the lowest is −21°F, on February 10, 2011.
The wettest calendar year on that record is 2008, with 42.73 in; the snowiest season is 1987–88, with 55.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00344019; records: ACIS (NOAA Regional Climate Centers), station USC00344019. Records use complete months only; a month missing more than three days is left out.
How sunny is Helena?
Over a year 82% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Helena, 4.8 kWh per square metre a day. July is the sunniest month (88%) and February the cloudiest (75%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 79% | 2.8 |
| February | 75% | 3.5 |
| March | 77% | 4.6 |
| April | 78% | 5.7 |
| May | 79% | 6.3 |
| June | 86% | 7.1 |
| July | 88% | 7.0 |
| August | 86% | 6.2 |
| September | 85% | 5.2 |
| October | 81% | 4.0 |
| November | 81% | 3.0 |
| December | 76% | 2.4 |
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 Helena need?
A normal year in Helena brings 4,162 heating degree days, 23% fewer than the median U.S. place (5,373), and 1,932 cooling degree days, 2.1 times the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,848 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 928 | 0 |
| February | 735 | 0 |
| March | 524 | 4 |
| April | 261 | 27 |
| May | 71 | 152 |
| June | 3 | 385 |
| July | 0 | 547 |
| August | 0 | 495 |
| September | 25 | 263 |
| October | 207 | 55 |
| November | 541 | 3 |
| December | 866 | 0 |
| Year (annual) | 4,162 | 1,932 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00344019. 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 Helena been warmer than normal lately?
2025 averaged 59.6°F, 0.8°F above the 1991-2020 normal of 58.8°F. 4 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 59.4°F | +0.6°F | 21.81 | 12.0 |
| 2022 | 58.9°F | +0.1°F | 26.61 | 22.5 |
| 2024 | 62.2°F | +3.4°F | 29.17 | 2.0 |
| 2025 | 59.6°F | +0.8°F | 34.99 | 8.6 |
Over 58 complete years from 1963 to 2025, the station's annual mean temperature rose at a fitted 1.9°F per century (+0.11°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00344019; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Helena's climate compare?
Helena is warmer than 24 of the other 133 places with their own NOAA record in Oklahoma, and wetter than 34. Across the 7,247 U.S. stations with normals, its annual mean of 58.8°F is warmer than 71%.
In the Köppen classification computed from these normals, Helena 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.
Which places near Helena share this climate record?
3 places have no NOAA station with 1991-2020 normals of their 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.
- Carmen, OK359 people · 11 mi W
- Goltry, OK252 people · 6 mi E
- Aline, OK171 people · 10 mi W
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 Helena's climate
What is the coldest month in Helena?
January, with a normal high of 47°F and a normal low of 23°F. The warmest is July (95°F by day, 70°F at night).
Does it snow in Helena?
Yes: 13 inches in a normal year, falling on 6 days with 0.1 inch or more, the most in December (3.4 inches).
What is the rainiest month in Helena?
June, with 4.42 in of precipitation in a normal year; the driest is January with 1.04 in.
What plant hardiness zone is Helena in?
The USDA's 2023 map puts Helena in zone 7a in ZIP code 73741, the nearest ZIP area. By the same method at Helena's NOAA station, the coldest night of a typical year reaches 2°F (30 years, 1991-2020): zone 7a.
How late can frost come in Helena?
In half of years the last 32°F night comes after April 9; in one year in ten it comes after April 23. Waiting until April 23 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Oklahoma climateThe statewide normals and every place in the state
- Lahoma, OK14 miles from this station, 59.2°F a year
- Cherokee, OK16 miles from this station, 59.1°F a year
- Great Salt Plains Dam, OK16 miles from this station, 59.2°F a year
- Fairview, OK23 miles from this station, 59.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made