Missouri weather and outdoor projects
Missouri has a continental climate with hot, humid summers and cold winters, and spring is stormy and often very wet. St. Louis and Kansas City both see summer highs in the 90s and winter nights well below freezing. The Ozarks in the south are a bit milder.
September and October are often the best months for exterior projects, with warm days and lower humidity. Spring can work between rain events, but watch for multi-day wet spells. Freeze-thaw cycles through winter make proper curing and sealing important for concrete driveways and steps.
Frost dates in Missouri
In St. Louis, the median last spring freeze (32°F) is around April 2 and the median first fall freeze is around November 4, a frost-free season of about 215 days.
In Kansas City, the median last spring freeze (32°F) is around April 13 and the median first fall freeze is around October 24, a frost-free season of about 193 days.
How Missouri compares with other states
St. Louis is tied for the 14th-shortest deck staining season of the 50 state main stations (4 good months). St. Louis is tied for the 17th-most days at 90°F or hotter of the 50 state main stations (47 a year). St. Louis is tied for the 18th-least humid summer afternoons of the 47 state main stations (49% humidity at 3 PM, June–August).
| Measure (St. Louis) | Value | Rank, highest first |
|---|---|---|
| Deck staining season | 4 good months | 20th of 50 |
| Frost-free season | 215 days | 22nd of 50 |
| Freezing nights | 85 a year | 28th of 50 |
| Rainy days | 71 a year with 0.1 in or more | 29th of 50 |
| Days at 90°F or hotter | 47 a year | 17th of 50 |
| Summer afternoons | 49% humidity at 3 PM, June–August | 28th of 47 |
Best time to stain a deck in Missouri
In St. Louis, the most reliable months are May–June and September–October. April and July–August can also work on the right days (average highs Apr 68°F, Jul 90°F, Aug 88°F). December–February is too cold, with average highs around 44°F. In March and November, nights average about 37°F, too cold for the coating to dry and cure overnight. In April, nights average about 47°F, so finish early on mild days and check the overnight low. July–August is hot, with highs near 89°F, so start early and keep out of full afternoon sun.
In Kansas City, the most reliable months are May–June and September. April, July–August and October can also work on the right days. November–February is too cold, with average highs around 44°F. In March, nights average about 34°F, too cold for the coating to dry and cure overnight. In April and October, nights average about 45°F, so finish early on mild days and check the overnight low. July–August is hot, with highs near 88°F, so start early and keep out of full afternoon sun.
Best time to paint outside in Missouri
In St. Louis, the most reliable months are April–June and September–October. March, July–August and November can also work on the right days. December–February is too cold, with average highs around 44°F. March and November are cool, with highs around 56°F, so choose the warmest afternoons. July–August is hot, with highs near 89°F, so start early and keep out of full afternoon sun.
In Kansas City, the most reliable months are May–June and September–October. March–April, July–August and November can also work on the right days. December–February is too cold, with average highs around 41°F. March and November are cool, with highs around 54°F, so choose the warmest afternoons. In April, nights average about 44°F, so finish early on mild days and check the overnight low. July–August is hot, with highs near 88°F, so start early and keep out of full afternoon sun.
Best time to pour concrete in Missouri
In St. Louis, the most reliable months are April–October. November–March averages about 17 nights a month at or below 32°F, so fresh concrete needs blankets or heated enclosures.
In Kansas City, the most reliable months are May–September. April and October can also work on the right days (average highs Apr 66°F, Oct 67°F). November–March averages about 20 nights a month at or below 32°F, so fresh concrete needs blankets or heated enclosures. April and October bring about 3 freezing nights a month, so pick a mild spell and keep curing blankets on hand.
Best time to seal a driveway in Missouri
In St. Louis, the most reliable months are May–September. April and October can also work on the right days (average highs Apr 68°F, Oct 69°F). November–March is too cold, with average highs around 49°F. In April and October, nights average about 48°F, so finish early on mild days and check the overnight low.
In Kansas City, the most reliable months are May–September. April and October can also work on the right days (average highs Apr 66°F, Oct 67°F). November–March is too cold, with average highs around 47°F. April and October are cool, with highs around 66°F, so choose the warmest afternoons.
Best time to fertilize or treat a lawn in Missouri
In St. Louis, the most reliable months are April–June and September–October. March, July–August and November can also work on the right days. December–February is too cold, with average highs around 44°F. March and November are cool, with highs around 56°F, so choose the warmest afternoons. July–August is hot, with highs near 89°F, so start early and keep out of full afternoon sun.
In Kansas City, the most reliable months are April–June and September–October. March, July–August and November can also work on the right days. December–February is too cold, with average highs around 41°F. March and November are cool, with highs around 54°F, so choose the warmest afternoons. July–August is hot, with highs near 88°F, so start early and keep out of full afternoon sun.
How the weather differs across Missouri
| Place | Hottest month avg high | Coldest month avg low | Rain per year | Last spring freeze | First fall freeze |
|---|---|---|---|---|---|
| St. Louis | 90°F | 24°F | 42 in | April 2 | November 4 |
| Kansas City | 88°F | 20°F | 39 in | April 13 | October 24 |
Of the places above, St. Louis has the most good months for staining, painting and concrete combined (16 job-months), and Kansas City has the fewest (12).
Monthly weather in St. Louis
| Month | Avg high | Avg low | Wet days* | Rain | 3 PM humidity | Freezing nights |
|---|---|---|---|---|---|---|
| January | 40°F | 24°F | 5 | 2.6 in | 57% | 24 |
| February | 46°F | 28°F | 5 | 2.2 in | 51% | 19 |
| March | 57°F | 37°F | 7 | 3.5 in | 46% | 10 |
| April | 68°F | 47°F | 8 | 4.7 in | 45% | 1 |
| May | 77°F | 58°F | 8 | 4.8 in | 49% | 0 |
| June | 86°F | 67°F | 7 | 4.5 in | 49% | 0 |
| July | 90°F | 71°F | 6 | 3.9 in | 49% | 0 |
| August | 88°F | 69°F | 5 | 3.4 in | 49% | 0 |
| September | 81°F | 61°F | 5 | 3.0 in | 47% | 0 |
| October | 69°F | 49°F | 6 | 3.1 in | 46% | 1 |
| November | 56°F | 37°F | 5 | 3.4 in | 50% | 9 |
| December | 45°F | 29°F | 5 | 2.5 in | 57% | 20 |
*Days with 0.1 inch of rain or more; column notes.
Monthly weather in Kansas City
| Month | Avg high | Avg low | Wet days* | Rain | 3 PM humidity | Freezing nights |
|---|---|---|---|---|---|---|
| January | 38°F | 20°F | 3 | 1.2 in | 56% | 27 |
| February | 44°F | 24°F | 3 | 1.5 in | 51% | 22 |
| March | 55°F | 34°F | 5 | 2.4 in | 46% | 14 |
| April | 66°F | 44°F | 7 | 4.0 in | 47% | 3 |
| May | 75°F | 54°F | 8 | 5.3 in | 53% | 0 |
| June | 84°F | 64°F | 7 | 5.3 in | 55% | 0 |
| July | 88°F | 68°F | 6 | 4.6 in | 54% | 0 |
| August | 87°F | 66°F | 6 | 4.2 in | 53% | 0 |
| September | 79°F | 58°F | 6 | 4.0 in | 52% | 0 |
| October | 67°F | 46°F | 5 | 3.3 in | 48% | 2 |
| November | 54°F | 34°F | 4 | 2.0 in | 51% | 13 |
| December | 42°F | 24°F | 3 | 1.6 in | 57% | 25 |
Source: NOAA NCEI U.S. Climate Normals 1991–2020 for ST LOUIS LAMBERT INTL AP, KANSAS CITY INTL AP. See how the ratings work and how late in fall you can stain, paint or seal.
Frequently asked questions
When is the best time to stain a deck in Missouri?
In St. Louis, May–June and September–October. In Kansas City, May–June and September.
When is the last frost in Missouri?
St. Louis: around April 2; Kansas City: around April 13.
Can you pour concrete in winter in Missouri?
Yes, with cold-weather practices: St. Louis averages about 63 freezing nights from December to February, so fresh concrete needs insulated blankets, a heated enclosure or an accelerated mix, and must not freeze in the first 48 hours. Many homeowners wait for spring.
What months are best for sealing a driveway in Missouri?
In St. Louis, May–September. In Kansas City, May–September.