Cincinnati Weather and the Best Exterior Cleaning Times
Weather decides when windows can be cleaned, when gutters overflow, and when algae grows. This page uses the official 1991-2020 climate normals for the Cincinnati area.
Data: NOAA 1991-2020 climate normals, Cincinnati/Northern Kentucky International Airport. Checked October 2026.
Key numbers
| Month | Precipitation (in) | Average temperature (F) |
|---|---|---|
| January | 3.30 | 31.4 |
| February | 3.17 | 34.7 |
| March | 4.16 | 43.6 |
| April | 4.53 | 54.6 |
| May | 4.67 | 64.1 |
| June | 4.75 | 72.3 |
| July | 3.83 | 75.9 |
| August | 3.43 | 74.9 |
| September | 3.11 | 68.1 |
| October | 3.35 | 56.2 |
| November | 3.23 | 44.4 |
| December | 3.73 | 35.6 |
Roughly one day in four reaches freezing
The Cincinnati/Northern Kentucky airport records about 100 days a year with a low at or below 32 F, around 27% of the year. On those mornings, cleaning solution can freeze on glass and surfaces, and exterior washing has to wait. Average temperatures from December through February run from about 31 to 36 F, which is why winter is the season for interior work.
March (43.6 F) and November (44.4 F) have average temperatures in the 40s, which is where exterior work becomes practical again in spring and winds down in fall.
A wet spring and early summer
Precipitation peaks from April through June, at 4.5 to 4.75 inches a month. Mild, damp weather feeds algae and mildew on shaded siding, decks and roofs, and heavy rain fills gutters with seeds and debris.
About 11 days a year bring an inch or more of rain. Those are the days when clogged gutters overflow and stain siding or pool water against a foundation, so gutter cleaning before spring and after leaf fall is a sensible rhythm.
Summer heat dries cleaning solution fast
Cincinnati averages 22 days a year at 90 F or hotter, plus a July average near 76 F. In the heat of direct sun, window cleaning solution dries before it can be wiped, leaving streaks. Working in shade or early in the day avoids it.
Sprinklers matter here too. Any water that dries on glass leaves behind its dissolved minerals, so keeping spray off windows prevents spots.
A practical schedule
Interior glass: March or April, with an optional winter touch-up. Exterior glass, frames and screens: mid-spring after pollen and seed fall, and again after the leaves drop in fall. Gutters: late spring and late fall. Soft washing siding and decks: late spring or early fall, when temperatures are mild and surfaces dry quickly.
The takeaway
Use spring and fall for exterior glass, siding and gutters, and keep winter for interior work.
Sources
See our services in Cincinnati, OH or window cleaning in cincinnati.