Weldon Spring, Missouri climate: Normal weather by month, frost dates and records
Weldon Spring's normal year runs from 21°F January nights to 88°F July afternoons, with 44.4 inches of precipitation and 14 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.9°C, January lows of −6°C, July highs of 31°C, 1,128 mm of precipitation a year.
- NOAA stationWeldon Spring NWS
- Station IDUSC00238805
- Location38.70°N 90.68°W
- Elevation610 ft (186 m)
- From the center2 miles
- Population5,304
On October 23, the normal high in Weldon Spring is 66°F and the normal low 43°F, and the chance of measurable rain or snow is 28%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Weldon Spring.
- Jan 39° 21°
- Feb 45° 24°
- Mar 55° 33°
- Apr 67° 44°
- May 76° 54°
- Jun 84° 63°
- Jul 88° 67°
- Aug 87° 65°
- Sep 80° 57°
- Oct 68° 46°
- Nov 55° 35°
- Dec 44° 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 Weldon Spring each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 21°F. The most precipitation falls in May (5.09 in), the least in February (2.43 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 39°F | 21°F | 30.3°F | 2.61 | 4.1 | 8 | <1 | 26 | 9 h 40 min |
| February | 45°F | 24°F | 34.6°F | 2.43 | 3.7 | 8 | <1 | 22 | 10 h 40 min |
| March | 55°F | 33°F | 44.2°F | 3.74 | 1.7 | 10 | <1 | 15 | 11 h 50 min |
| April | 67°F | 44°F | 55.4°F | 4.70 | 0.2 | 10 | <1 | 4 | 13 h 10 min |
| May | 76°F | 54°F | 65.0°F | 5.09 | 0.0 | 13 | 1 | <1 | 14 h 20 min |
| June | 84°F | 63°F | 73.5°F | 4.72 | 0.0 | 10 | 6 | <1 | 14 h 50 min |
| July | 88°F | 67°F | 77.4°F | 3.92 | 0.0 | 8 | 13 | <1 | 14 h 40 min |
| August | 87°F | 65°F | 76.0°F | 3.58 | 0.0 | 8 | 11 | <1 | 13 h 40 min |
| September | 80°F | 57°F | 68.4°F | 3.50 | 0.0 | 7 | 4 | <1 | 12 h 30 min |
| October | 68°F | 46°F | 56.9°F | 3.37 | 0.0 | 9 | <1 | 2 | 11 h 20 min |
| November | 55°F | 35°F | 45.2°F | 3.69 | 0.8 | 8 | <1 | 13 | 10 h 10 min |
| December | 44°F | 26°F | 35.0°F | 3.07 | 3.0 | 8 | <1 | 23 | 9 h 30 min |
| Year (annual) | 66°F | 45°F | 55.2°F | 44.42 | 13.5 | 107 | 36 | 105 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 4°C | −6°C | −0.9°C | 66 mm | 10 cm |
| February | 7°C | −4°C | 1.4°C | 62 mm | 9 cm |
| March | 13°C | 1°C | 6.8°C | 95 mm | 4 cm |
| April | 19°C | 7°C | 13.0°C | 119 mm | 1 cm |
| May | 24°C | 12°C | 18.3°C | 129 mm | 0 cm |
| June | 29°C | 17°C | 23.1°C | 120 mm | 0 cm |
| July | 31°C | 20°C | 25.2°C | 100 mm | 0 cm |
| August | 30°C | 19°C | 24.4°C | 91 mm | 0 cm |
| September | 27°C | 14°C | 20.2°C | 89 mm | 0 cm |
| October | 20°C | 8°C | 13.8°C | 86 mm | 0 cm |
| November | 13°C | 2°C | 7.3°C | 94 mm | 2 cm |
| December | 7°C | −3°C | 1.7°C | 78 mm | 8 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00238805; 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 Weldon Spring?
Normal highs sit between 65°F and 85°F in April, May, June, September and October. Of those, September has the fewest days with rain (7).
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 USC00238805.
When is the last frost in Weldon Spring?
In Weldon Spring, the last spring frost (32°F) comes after April 10 in half of years and after April 26 in one year in ten; the first autumn frost comes before October 26 in half of years and before October 12 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 101 year in 10 after April 26; 9 in 10 after March 26
- First autumn frost, half of years before
- October 261 year in 10 before October 12; 9 in 10 before November 8
NOAA puts the median frost-free season at 199 days, and the season without a hard freeze (28°F) at 221 days.
A hard freeze (28°F) comes after March 31 in half of springs and before November 5 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Weldon Spring in zone 6b in ZIP code 63304. By the map's own method, the average of each year's coldest night over 1991-2020, Weldon Spring's NOAA station is in zone 6b: the coldest night of a typical year reaches −1°F (22 complete years).
Frost dates for every NOAA station in Missouri · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00238805; 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 Weldon Spring?
In a normal year in Weldon Spring, 36 days a year reach 90°F (1 of them 100°F or more), 105 nights fall to 32°F or colder and 107 days bring measurable precipitation.
- Days at 90°F or more
- 36a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 105a normal year
- Days that stay below freezing
- 22high of 32°F or less
- Days with 0.01 inch of precipitation
- 107a normal year
- Days with 1 inch of snow or more
- 5a normal year
The highest temperature in this station's record (since 1957) is 109°F, on August 18, 2000; the lowest is −23°F, on January 17, 1977.
The wettest calendar year on that record is 2008, with 62.75 in; the snowiest season is 1959–60, with 39.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00238805; records: ACIS (NOAA Regional Climate Centers), station USC00238805. Records use complete months only; a month missing more than three days is left out.
How sunny is Weldon Spring?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Weldon Spring, 4.2 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (66%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 67% | 2.1 |
| February | 66% | 2.8 |
| March | 67% | 3.8 |
| April | 73% | 5.0 |
| May | 74% | 5.6 |
| June | 81% | 6.4 |
| July | 82% | 6.3 |
| August | 81% | 5.6 |
| September | 81% | 4.8 |
| October | 76% | 3.4 |
| November | 72% | 2.4 |
| December | 66% | 1.8 |
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 Weldon Spring need?
A normal year in Weldon Spring brings 4,866 heating degree days, 9% fewer than the median U.S. place (5,373), and 1,312 cooling degree days, 45% more than the median (908). Six months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,025 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,077 | 0 |
| February | 851 | 0 |
| March | 647 | 4 |
| April | 312 | 24 |
| May | 102 | 101 |
| June | 10 | 264 |
| July | 0 | 385 |
| August | 2 | 344 |
| September | 53 | 155 |
| October | 281 | 32 |
| November | 599 | 3 |
| December | 931 | 0 |
| Year (annual) | 4,866 | 1,312 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00238805. 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 Weldon Spring been warmer than normal lately?
2024 averaged 57.8°F, 2.6°F above the 1991-2020 normal of 55.2°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 56.4°F | +1.2°F | 39.68 | 14.3 |
| 2022 | 55.2°F | at normal | 45.73 | 16.0 |
| 2023 | 57.6°F | +2.4°F | 32.13 | 2.0 |
| 2024 | 57.8°F | +2.6°F | 51.52 | 13.7 |
Over 32 complete years from 1958 to 2024, the station's annual mean temperature rose at a fitted 3.7°F per century (+0.21°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00238805; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Weldon Spring's climate compare?
Weldon Spring is warmer than 64 of the other 133 places with their own NOAA record in Missouri, and wetter than 69. Across the 7,247 U.S. stations with normals, its annual mean of 55.2°F is warmer than 61%.
In the Köppen classification computed from these normals, Weldon Spring 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 Weldon Spring share this climate record?
8 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.
- O'Fallon, MOalso near: St. Peters (7 mi, 55.3°F a year); St Louis Spirit of St. Louis Airport (10 mi, 56.1°F a year)95,355 people · 6 mi N
- Wentzville, MO48,646 people · 13 mi NW
- Lake St. Louis, MO19,160 people · 8 mi NW
- Dardenne Prairie, MO14,407 people · 3 mi NW
- New Melle, MO547 people · 11 mi W
- Josephville, MO517 people · 11 mi NW
- Weldon Spring Heights, MO92 people · 0 mi N
- Defiance, MO80 people · 7 mi SW
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 Weldon Spring's climate
What is the coldest month in Weldon Spring?
January, with a normal high of 39°F and a normal low of 21°F. The warmest is July (88°F by day, 67°F at night).
Does it snow in Weldon Spring?
Yes: 14 inches in a normal year, falling on 12 days with 0.1 inch or more, the most in January (4.1 inches).
What is the rainiest month in Weldon Spring?
May, with 5.09 in of precipitation in a normal year; the driest is February with 2.43 in.
What plant hardiness zone is Weldon Spring in?
The USDA's 2023 map puts Weldon Spring in zone 6b in ZIP code 63304. By the same method at Weldon Spring's NOAA station, the coldest night of a typical year reaches −1°F (22 years, 1991-2020): zone 6b.
How late can frost come in Weldon Spring?
In half of years the last 32°F night comes after April 10; in one year in ten it comes after April 26. Waiting until April 26 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Missouri climateThe statewide normals and every place in the state
- St Louis Spirit of St. Louis Airport, MO3 miles from this station, 56.1°F a year
- St. Peters, MO7 miles from this station, 55.3°F a year
- St. Louis, MO17 miles from this station, 57.4°F a year
- Washington, MO19 miles from this station, 54.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made