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Outdoor Project Weather in Ontario, CA

This page runs Ontario's forecast against all six task rulesets at once. Verdicts load live above; the month-by-month matrix below — built from NOAA 1991–2020 normals — shows when each job's season opens. Lawn Seeding gets the most calendar here: 250 workable days a year.

Six tasks · one forecast · California

MayBest overall month
Lawn SeedingFriendliest task
1,363 task-daysWorkable task-days/yr
6Tasks tracked
Average of all six tasks

Today at a glance

Verdicts load live from the 10-day forecast; without JavaScript this column stays blank and the year-round matrix below still answers the planning question.
Task	Today	Best months here	Full 10-day check
Deck Staining	—	May, Oct, Apr	Stain a Deck in Ontario →
Exterior Painting	—	May, Oct, Apr	Paint Outside in Ontario →
Driveway Sealing	—	May, Oct, Jun	Seal a Driveway in Ontario →
Concrete Pouring	—	May, Oct, Apr	Pour Concrete in Ontario →
Roof Coating	—	May, Oct, Apr	Coat a Roof in Ontario →
Lawn Seeding	—	Jan, Mar, May	Seed a Lawn in Ontario →

Keep the tour going — compare this calendar with Oceanside, CA behind you or Orange, CA up next.

Project weather, month by month

Workable days per month by task, from NOAA 1991–2020 normals for ONTARIO INTL AP, CA US. Darker = more workable days.
Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Deck Staining	26	23	25	27	29	26	0	0	10	29	26	26
Exterior Painting	26	23	25	27	29	26	0	0	10	29	26	26
Driveway Sealing	0	0	0	20	29	26	0	0	10	29	11	0
Concrete Pouring	26	23	25	27	29	26	0	0	10	29	26	26
Roof Coating	26	23	25	27	29	26	0	0	10	29	26	26
Lawn Seeding	31	29	31	30	31	11	0	0	0	26	30	31

Which task gets the most weather in Ontario?

Lawn Seeding250days/yr
Deck Staining247days/yr
Exterior Painting247days/yr
Concrete Pouring247days/yr
Roof Coating247days/yr
Driveway Sealing125days/yr

Season edges differ by task — that's the point of checking six at once. In Ontario the earliest opener starts around April and the last holdout closes after June. A week that fails the paint rules on humidity can still pass seeding, and a frost that ends concrete season leaves sealing untouched until nights slip under 50°F.

If you only open one full check, make it lawn seeding — Ontario's longest season at 250 workable days.

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Full 10-day checks

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Climatology: NOAA 1991–2020 normals via ONTARIO INTL AP, CA US (3.1 km from Ontario center); live outlook by Open-Meteo.