St. Louis, Missouri Weather
Thunder quiets the land. Day 93 of summer. Read this microseason across nine climate regions →
St. Louis weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 1:53 AM CDT · Open-Meteo
- TodaySep 21Heavy Rain83%2.3″74°65°—
- TuesdaySep 22Overcast——66°61°-8°
- WednesdaySep 23Overcast——77°61°+11°
- ThursdaySep 24Overcast——80°60°+3°
- FridaySep 25Overcast——81°64°+1°
- SaturdaySep 26Overcast——71°65°-10°
- SundaySep 27Overcast10%—82°63°+11°
Air quality now AQI 47 · Good
AQI 47 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM scrubbed by 5 hours of recent rain — PM2.5 down to 5.6 µg/m³, PM10 to 5.8 µg/m³.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
PM × Wind × Precip
PM scrubbed by 5 hours of recent rain — PM2.5 down to 5.6 µg/m³, PM10 to 5.8 µg/m³.
- PM2.5/PM10
- 0.97
- Wind
- light
- Recent rain
- 5h in last 6h
- Pattern
- washed out
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
September dries up ditches or breaks down bridges.
- Moonrise
- 4:30 PM
- Moonset
- 1:26 AM
- In sign
- ♑︎ Capricorn
Thunder quiets the land
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
St. Louis at a glance
- Today vs. normal: Today averages 70°F (high 74°F, low 65°F), about the 70°F normal for Sep 21
- Last frost: April 1 (1991–2020 median, NOAA station 2 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant garlic (overwinter); harvest tomatoes, peppers, beans, summer squash, winter squash
15-Day Forecast — St. Louis
- Mon74°65°83%
- Tue66°61°5%
- Wed77°61°0%
- Thu80°60°0%
- Fri81°64°1%
- Sat71°65°7%
- Sun82°63°10%
- Mon82°61°10%
- Tue76°63°29%
- Wed82°64°21%
- Thu79°59°9%
- Fri83°60°6%
- Sat82°68°10%
- Sun96°74°7%
- Mon88°75°19%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near St. Louis
Interactive wind and temperature map centered on St. Louis — it loads in your browser. Open the full weather map.
Right now in the garden
Fall planting + final harvests
As of September 21, the season's first frost (typically November 4) is approaching. Pick what frost-tender plants still carry before the next cold front. This city's planting calendar for September: plant garlic (overwinter); harvest tomatoes, peppers, beans, summer squash, and winter squash.
SPC Convective Outlook
Storm Prediction Center — St. Louis
SPC includes St. Louis in the general thunderstorm area today — no severe risk, but storms are possible.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWNONENo severe risk
- DAY 3NONENo severe risk
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook.
Sun & seasons in St. Louis
St. Louis sits in St. Louis County, where the year’s longest day runs 14h 52m of daylight and its shortest just 9h 28m — a swing of +5h 24m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
St. Louis is the state’s largest city. The nearest town St. Louis tracks is O'Fallon, roughly 27 miles to the WNW.
Air quality in St. Louis
Air quality in St. Louis’s county has held roughly steady since 2020; its cleanest year on record was 2020 (median AQI 54). See the full air-quality history for St. Louis.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| March | lettuce, peas, spinach, radishes | — |
| April | lettuce, peas, spinach, radishes | lettuce, spinach, radishes |
| May | tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, spinach, beans, summer squash, garlic |
| July | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, garlic |
| August | beans, squash, fall brassicas, carrots | tomatoes, peppers, beans, summer squash, winter squash |
| September | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash |
| October | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash, fall brassicas, carrots |
| November | — | fall brassicas, carrots |
A year in weather
July is St. Louis's warmest stretch (~81°F) and January its coldest (~31°F); precipitation crests in May at 4.4 inches and ebbs in January to 2.1 inches.
| Month | Mean temp | Precip |
|---|---|---|
| January | 31° | 2.1″ |
| February | 35° | 2.3″ |
| March | 45° | 4.0″ |
| April | 57° | 4.3″ |
| May | 66° | 4.4″ |
| June | 75° | 4.2″ |
| July | 81° | 2.7″ |
| August | 80° | 2.9″ |
| September | 72° | 2.6″ |
| October | 60° | 2.8″ |
| November | 45° | 3.6″ |
| December | 34° | 3.0″ |
Regional context
Similar climates Wellston, MO, Hillsdale, MO, Uplands Park, MO
St. Louis's climate, from modelled 1991-2020 normals (EC_Earth3P_HR model via Open-Meteo), pairs 31°F Januarys with 81°F Julys — a 50°F swing. About 39.1 inches of precipitation falls each year.
St. Louis's precipitation spreads evenly across the seasons: May peaks at 4.4 inches, while January holds 2.1 inches — no season dominates St. Louis's rain calendar. That even rhythm groups St. Louis with places like Wellston, MO, Hillsdale, MO and Uplands Park, MO.
By April 1 the frosts ease in St. Louis, opening the season for peas, lettuce, spinach, and radishes. In St. Louis, warm-season transplants — tomatoes, peppers, basil — wait two weeks past St. Louis's frost date. It shuts near November 4, when freezes return to St. Louis and tender plants need cover. In about half of years, St. Louis's last freeze comes after April 1.
Similar climates: Wellston, MO, Hillsdale, MO, Uplands Park, MO, Pine Lawn, MO, Velda Village Hills, MO.
Frequently asked
- When does it freeze in St. Louis?
- St. Louis's last spring frost lands near April 1, and in St. Louis the first fall frost follows around November 4.
- What is the rainy season in St. Louis?
- St. Louis sees its heaviest rain in May (around 4.4 inches), part of roughly 39 inches a year.
- What is the warmest month in St. Louis?
- St. Louis peaks in July, when the mean runs near 81°F.
- What is the coldest month in St. Louis?
- January is St. Louis's coldest month, averaging about 31°F.
- When can I start a vegetable garden in St. Louis?
- Hardy spring crops go in near April 1 in St. Louis; tender peppers and squash wait 10–14 days.
- What hardiness zone is St. Louis?
- Because St. Louis bottoms near 31°F in January, that winter low sets St. Louis's USDA zone — verify by ZIP.
- What is the 10-day forecast for St. Louis?
- St. Louis's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in St. Louis?
- See this week's day-by-day rain chances for St. Louis in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in St. Louis?
- Current conditions for St. Louis and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the St. Louis forecast updated?
- The St. Louis forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in St. Louis?
- Today's sunrise and sunset times for St. Louis are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for St. Louis?
- The next few days in St. Louis's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
St. Louis sits at 38.6°N; its climate zone is humid subtropical (Köppen approximation).
ZIP codes in St. Louis
- 63101
- 63102
- 63103
- 63104
- 63106
- 63107
- 63108
- 63109
- 63110
- 63111
- 63112
- 63113
- 63115
- 63116
- 63118
- 63120
- 63137
- 63139
- 63143
- 63147
- 63150
- 63155
- 63156
- 63157
- 63158
- 63160
- 63163
- 63164
- 63166
- 63169
- 63177
- 63178
- 63179
- 63180
- 63188
- 63197