January and February: the freezing line runs through the day
At Newark Airport the 1991-2020 normals set January's average at 32.8 degrees, between a 25.5 low and a 40 high, with 9.1 inches of snow. February's normals are 35.1 degrees on average and 10.1 inches of snowfall. A day that opens below freezing and closes above it melts the snowpack, drives water to the eaves and freezes it there again. Ice at the edge deserves a photograph from the ground. The University of Massachusetts says chipping it does more harm than good, so the hammer can stay in the shed.
The year at a glance
| Month | Average at Newark Airport | From the ground |
|---|---|---|
| January | 32.8 degrees, 9.1 inches of snow | Photograph ice at the eaves and watch the top-floor ceilings |
| February | 35.1 degrees, 10.1 inches of snow | Note the thaw days; leave the hammer in the shed |
| March | 42.5 degrees, 5.6 inches of snow | First binocular lap after winter |
| April | 53.3 degrees, 3.87 inches of precipitation | Attic hatch look after the first steady rain |
| July | 78.2 degrees, 4.66 inches of precipitation | Flat-roof drains, from a window |
| September | 69.2 degrees, 3.82 inches of precipitation | Photos after any storm; wires first |
| October | 57.5 degrees, 3.79 inches of precipitation | Gutters and downspouts after the leaves fall |
| December | 38 degrees, 5.4 inches of snow | Last ceiling check before the snow |
March and April: a first lap after winter
March averages 42.5 degrees and gets 4.13 inches of precipitation, with 5.6 inches of snow. April averages 53.3 degrees and 3.87 inches. The first dry afternoon suits a lap around the house with binoculars, looking for lifted edges, bare patches and flashing that has pulled away. The attic hatch and a flashlight come next. That is the order the asphalt roofing trade group lays out in its Sandy damage guidance: ground first, attic second.
July: heat, and the flat roof's drains
July at Newark Airport averages 78.2 degrees, with an 86.9 high and a 69.4 low, and 4.66 inches of precipitation. The Department of Energy says a reflective roof can stay more than 50 degrees cooler than a dark one. A flat roof tests its drains in July rain. Look from an upstairs window a day or two after a downpour. Water still there at 48 hours counts as ponding, by the asphalt roofing trade group's definition.
August and September: the storm months
Isaias reached New Jersey on 4 August 2020 with the strongest statewide winds since Sandy, and over a million customers lost electricity. Ida's remnants followed in 2021: Newark Airport measured 8.44 inches across the first two days of September. A normal September there brings 3.82 inches, and the record month reached 10.5. After a storm, treat any downed wire as live and dial 911 or the utility. NIOSH puts the ladder distance from overhead lines at ten feet or more.
October: leaves and gutters
October averages 57.5 degrees and 3.79 inches of precipitation, with 0.2 inches of snow in the normals. The leaves come down in the same weeks. After the first big drop, look from the ground at the gutters for sagging runs and spilled water on the siding. Rutgers recommends aiming downspout discharge at soil that can absorb it, away from the foundation.
December: the last look before snow
December averages 38 degrees, with a 44.8 high and a 31.2 low, plus 4.14 inches of precipitation and 5.4 inches of snow. Winter is close. A last look at the ceilings and the attic hatch catches a slow stain before the cold arrives. The Building America Solution Center puts air sealing first for ice dams, with insulation and ventilation after it, and a roofer can read an attic with that order in mind.
Which month are you in?
Whatever the month, two moves apply: photograph, then compare. For winter ice, read about ice dam damage. For a spring look-over, see roof inspection. Your move: call (862) 418-5296 and give a short account of what the roof is up to this month.