WorkWindow

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.

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.
TaskTodayBest months hereFull 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 →

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.
TaskJanFebMarAprMayJunJulAugSepOctNovDec
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

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.

Full 10-day checks

California

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