Best days to pour concrete in San Francisco, CA this week
Here's the next 7 days for pouring concrete in San Francisco, checked hour by hour against the published thresholds. Below it: what San Francisco's 1991–2020 climate averages say about the months that usually work.
This week in San Francisco
Asking the sky…
Fairsky is not a substitute for official warnings. For warnings, go to weather.gov. Verdicts are guidance, not guarantees. Your product's label always wins.
When pouring concrete usually works in San Francisco
- On 1991–2020 averages, San Francisco's normal lows stay above 40°F (the cold-weather line in ACI 306) with highs of 85°F or cooler in every month of the year.
- No month in San Francisco's 1991–2020 averages has normal lows of 40°F or colder, so cold-weather concreting is the exception here, not the season.
- Of the mild months, July averages the fewest days with 0.10" or more of rain (0.0); a pour wants 24 rain-free hours.
| Month | Avg high | Avg low | Days ≥0.10" rain | Nights ≤32°F | Lows above 40°F, highs ≤85°F |
|---|---|---|---|---|---|
| January | 58° | 47° | 8.0 | 0.0 | Yes |
| February | 60° | 48° | 7.9 | 0.0 | Yes |
| March | 62° | 49° | 6.7 | 0.0 | Yes |
| April | 63° | 50° | 4.2 | 0.0 | Yes |
| May | 64° | 51° | 2.1 | 0.0 | Yes |
| June | 67° | 53° | 0.6 | 0.0 | Yes |
| July | 66° | 54° | 0.0 | 0.0 | Yes |
| August | 68° | 56° | 0.1 | 0.0 | Yes |
| September | 70° | 56° | 0.3 | 0.0 | Yes |
| October | 70° | 54° | 2.0 | 0.0 | Yes |
| November | 64° | 51° | 4.8 | 0.0 | Yes |
| December | 58° | 47° | 8.0 | 0.0 | Yes |
Station: San Francisco Dwtn (NOAA NCEI USW00023272), about 1 km from central San Francisco. “Rain days” count days with 0.10" or more of precipitation. “Lows above 40°F, highs ≤85°F” checks the monthly averages only; any given week can be warmer, colder or wetter.
The rules we check
- Needs 4 hours in a row of daylight.
- Air at least 40°F (32–39°F is borderline).
- No hotter than 85°F (86–90°F is borderline).
- Wind at or under 20 mph. (Fairsky default: no source gave a number)
- Rain chance at or below 20%. (Fairsky default: no source gave a number)
- No rain for 24 hours after you finish.
- Stays above 32°F for 48 hours after (below 40°F, plan on blankets).
Your product's label always wins. Labels differ by product; in the app you can enter your label's temperature range and rain-free hours, and the verdict uses them instead.
Sources: ACI 306R-16 cold-weather concreting (STRUCTURE magazine) · NIH technical bulletin: cold weather concreting · Euclid Chemical: preventing rapid evaporation · Quikrete 5000 data sheet
More home and yard jobs in San Francisco
- Stain a deckDeck and fence stain: 50–90°F, dry wood, 24 rain-free hours after.
- Paint a house exteriorExterior latex paint: 40°F and up, 5°F above the dew point, 4 dry hours after.
- Spray weedsWeed killer: 3–10 mph wind, 45–85°F, 4 rain-free hours after.
- Apply pre-emergentCrabgrass pre-emergent: before soil holds 55°F (about 200 GDD), then water it in.
- Plant grass seedCool-season grass seed: soil about 50–65°F, highs 60–80°F, no washout rain.
- Seal a drivewayAsphalt sealcoat: 55°F and rising, 50°F overnight, 36 rain-free hours.
- Cover plants for frostFrost watch: cover at 34°F, or 36°F on clear, calm nights; 28°F is a hard freeze.
The app covers 47 activities in all, from mowing to a round of golf: see every activity and its rules.
Pour concrete in nearby cities
- San Jose, CA42 miles away
- Stockton, CA63 miles away
- Sacramento, CA75 miles away
- Modesto, CA78 miles away
- Fresno, CA162 miles away
- Bakersfield, CA251 miles away
All pour concrete cities: Pour concrete, by city · Home and yard in California
Questions
What's the best month to pour concrete in San Francisco?
On 1991–2020 averages, July usually fits best in San Francisco. Any given week can still be wrong for it, which is what the live verdict above is for.
How is this verdict made?
We take the National Weather Service hourly forecast for San Francisco and check each hour against the thresholds listed above. The result is guidance, not a guarantee; your product's label always wins.
Is it too cold to pour concrete in San Francisco this week?
If the air is expected at or below 40°F in the first 48 hours, ACI calls it cold-weather concreting and the slab needs protection; below freezing, don't pour without a plan. The verdict above watches those nights.
Fairsky is not a substitute for official warnings. For warnings, go to weather.gov.
Live forecasts: National Weather Service / NOAA (public domain), fetched by your browser. Climate averages: NOAA NCEI U.S. Climate Normals, 1991–2020 (public domain). Activity thresholds: product data sheets, ACI and university extension guidance, linked on each page; your product’s label wins.