Mountain Lakes, NJ climate
Mountain Lakes has chilly winters and warm summers, with plenty of rain. A typical July afternoon reaches 85°, a January night drops to 20°, and about 28 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Mountain Lakes feels like
Winter
Spring
Summer
Fall
Mountain Lakes weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 38° | 20° | 3.6" | 9.6" | 11 | 20° – 36° |
| February | 41° | 22° | 2.7" | 7.7" | 9 | 19° – 37° |
| March | 49° | 29° | 4.0" | 5.3" | 11 | 32° – 48° |
| April | 61° | 38° | 4.0" | 1.4" | 10 | 46° – 54° |
| May | 72° | 48° | 4.0" | 0 | 11 | 56° – 65° |
| June | 80° | 57° | 4.7" | 0 | 11 | 66° – 71° |
| July | 85° | 62° | 4.6" | 0 | 9 | 69° – 77° |
| August | 83° | 61° | 4.4" | 0 | 9 | 68° – 75° |
| September | 76° | 54° | 4.4" | 0 | 8 | 62° – 69° |
| October | 64° | 42° | 4.5" | 0 | 8 | 49° – 60° |
| November | 53° | 33° | 3.6" | 0.2" | 8 | 38° – 48° |
| December | 42° | 26° | 4.3" | 3.9" | 11 | 27° – 45° |
| Year | 62° | 41° | 48.9" | 28.1" | 115 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Mountain Lakes
Mountain Lakes gets 49 inches of rain and melted snow a year. June is the wettest month and February the driest. Rain or snow falls on about 115 days a year.
About 189 frost-free days a year
In half of years the last 32° night comes by April 17 and the first one by October 23. That leaves about 189 frost-free days for gardens, longer than 63% of U.S. towns.
Heating and cooling a home in Mountain Lakes
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Mountain Lakes, 87% of that work is heating and 13% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Mountain Lakes and its neighbors
Mountain Lakes borders 3 towns with climate data. January nights across them vary by 0.7°. Boonton has the coldest January nights (20°) and Parsippany-Troy Hills the hottest July afternoons (86°). Mountain Lakes’s January low is 20° and its July high 85°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Mountain Lakes compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Mountain Lakes averaged 2.0° warmer than the 1900s. The biggest change is in December (+3.5°). The shift is larger than in 94% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Mountain Lakes’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 19° to 37°. June is the most reliable, staying within 6°.
Common questions about Mountain Lakes’s climate
What is the coldest month in Mountain Lakes?
January, with a typical high of 38° and a low of 20°.
What is the hottest month in Mountain Lakes?
July, with a typical high of 85° and a low of 62°. About 16 days a year reach 90°.
How much snow does Mountain Lakes get?
About 28 inches in a normal winter, most of it in January.
When is the first frost in Mountain Lakes?
In half of years the first 32° night comes by October 23, and the last spring frost by April 17.
What is the rainiest month in Mountain Lakes?
June, with 4.7 inches of rain and melted snow. The year totals 49 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Mountain Lakes itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Oak Ridge Rsvr, NJ (11 mi, snow) and Boonton 1 Se, NJ (2 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.