Mount Sinai, New York climate: Normal weather by month, frost dates and records
Mount Sinai's normal year runs from 26°F January nights to 83°F July afternoons, with 48.5 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.6°C, January lows of −3°C, July highs of 28°C, 1,232 mm of precipitation a year.
- NOAA stationMount Sinai
- Station IDUSC00305606
- Location40.93°N 73.02°W
- Elevation50 ft (15 m)
- From the centerunder 1 mile
- Population (census place)11,876
On October 14, the normal high in Mount Sinai is 65°F and the normal low 49°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Mount Sinai.
- Jan 41° 26°
- Feb 43° 28°
- Mar 50° 33°
- Apr 64° 43°
- May 72° 51°
- Jun 78° 61°
- Jul 83° 68°
- Aug 82° 67°
- Sep 75° 61°
- Oct 65° 49°
- Nov 56° 40°
- Dec 46° 32°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Mount Sinai each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 26°F. The most precipitation falls in March (4.65 in), the least in February (3.20 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 41°F | 26°F | 33.7°F | 3.71 | – | <1 | 22 | 9 h 30 min |
| February | 43°F | 28°F | 35.3°F | 3.20 | – | <1 | 19 | 10 h 40 min |
| March | 50°F | 33°F | 41.4°F | 4.65 | – | <1 | 15 | 11 h 50 min |
| April | 64°F | 43°F | 53.2°F | 4.42 | – | <1 | 3 | 13 h 20 min |
| May | 72°F | 51°F | 61.6°F | 3.89 | – | <1 | <1 | 14 h 30 min |
| June | 78°F | 61°F | 69.6°F | 3.93 | – | 1 | <1 | 15 h 10 min |
| July | 83°F | 68°F | 75.3°F | 3.88 | – | 5 | <1 | 14 h 50 min |
| August | 82°F | 67°F | 74.4°F | 4.02 | – | 2 | <1 | 13 h 50 min |
| September | 75°F | 61°F | 68.0°F | 4.30 | – | 1 | <1 | 12 h 30 min |
| October | 65°F | 49°F | 56.8°F | 4.24 | – | 1 | <1 | 11 h 10 min |
| November | 56°F | 40°F | 48.2°F | 3.70 | – | <1 | 6 | 10 h |
| December | 46°F | 32°F | 39.1°F | 4.56 | – | <1 | 14 | 9 h 20 min |
| Year (annual) | 63°F | 47°F | 54.7°F | 48.50 | – | 9 | 79 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 5°C | −3°C | 0.9°C | 94 mm |
| February | 6°C | −2°C | 1.8°C | 81 mm |
| March | 10°C | 0°C | 5.2°C | 118 mm |
| April | 18°C | 6°C | 11.8°C | 112 mm |
| May | 22°C | 11°C | 16.4°C | 99 mm |
| June | 26°C | 16°C | 20.9°C | 100 mm |
| July | 28°C | 20°C | 24.1°C | 99 mm |
| August | 28°C | 19°C | 23.6°C | 102 mm |
| September | 24°C | 16°C | 20.0°C | 109 mm |
| October | 18°C | 9°C | 13.8°C | 108 mm |
| November | 13°C | 5°C | 9.0°C | 94 mm |
| December | 8°C | 0°C | 3.9°C | 116 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Islip (11 miles away), gets 32 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00305606; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Mount Sinai?
Normal highs sit between 65°F and 85°F in May, June, July, August and September.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00305606.
When is the last frost in Mount Sinai?
In Mount Sinai, the last spring frost (32°F) comes after April 4 in half of years and after April 19 in one year in ten; the first autumn frost comes before November 7 in half of years and before October 20 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 41 year in 10 after April 19; 9 in 10 after March 23
- First autumn frost, half of years before
- November 71 year in 10 before October 20; 9 in 10 before November 24
NOAA puts the median frost-free season at 215 days, and the season without a hard freeze (28°F) at 241 days.
A hard freeze (28°F) comes after March 27 in half of springs and before November 22 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Mount Sinai in zone 7b in ZIP code 11766.
Frost dates for every NOAA station in New York · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00305606; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Mount Sinai?
In a normal year in Mount Sinai, 9 days a year reach 90°F and 79 nights fall to 32°F or colder.
- Days at 90°F or more
- 9a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 79a normal year
- Days that stay below freezing
- 14high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00305606.
How sunny is Mount Sinai?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Mount Sinai, 4.0 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (66%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 67% | 1.9 |
| February | 70% | 2.8 |
| March | 71% | 3.8 |
| April | 73% | 5.0 |
| May | 73% | 5.6 |
| June | 78% | 6.1 |
| July | 82% | 6.2 |
| August | 81% | 5.5 |
| September | 79% | 4.5 |
| October | 72% | 3.0 |
| November | 72% | 2.1 |
| December | 66% | 1.6 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Mount Sinai need?
A normal year in Mount Sinai brings 4,698 heating degree days, 13% fewer than the median U.S. place (5,373), and 982 cooling degree days, 8% more than the median (908). Six months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,534 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 972 | 0 |
| February | 830 | 0 |
| March | 731 | 0 |
| April | 360 | 7 |
| May | 143 | 36 |
| June | 24 | 164 |
| July | 0 | 319 |
| August | 1 | 292 |
| September | 50 | 139 |
| October | 278 | 24 |
| November | 507 | 1 |
| December | 803 | 0 |
| Year (annual) | 4,698 | 982 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00305606. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Mount Sinai's climate compare?
Mount Sinai is warmer than 127 of the other 130 places with their own NOAA record in New York, and wetter than 93. Across the 7,247 U.S. stations with normals, its annual mean of 54.7°F is warmer than 59%.
In the Köppen classification computed from these normals, Mount Sinai is Cfa: temperate, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Mount Sinai share this climate record?
10 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Coram, NY41,527 people · 4 mi S
- Selden, NY21,707 people · 4 mi S
- Rocky Point, NY13,931 people · 4 mi E
- Miller Place, NY11,743 people · 1 mi NE
- Middle Island, NY11,086 people · 5 mi SE
- Terryville, NY10,962 people · 2 mi SW
- Port Jefferson, NY8,189 people · 2 mi W
- Port Jefferson Station, NY7,605 people · 2 mi W
- Sound Beach, NY7,207 people · 3 mi NE
- Shoreham, NY524 people · 6 mi E
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Mount Sinai's climate
What is the coldest month in Mount Sinai?
January, with a normal high of 41°F and a normal low of 26°F. The warmest is July (83°F by day, 68°F at night).
Does it snow in Mount Sinai?
Yes. NOAA publishes no 1991-2020 snowfall normal for Mount Sinai's NOAA station; the nearest record that keeps one, Islip (11 miles away), records 32 inches of snow in a normal year.
What is the rainiest month in Mount Sinai?
March, with 4.65 in of precipitation in a normal year; the driest is February with 3.20 in.
What plant hardiness zone is Mount Sinai in?
The USDA's 2023 map puts Mount Sinai in zone 7b in ZIP code 11766.
How late can frost come in Mount Sinai?
In half of years the last 32°F night comes after April 4; in one year in ten it comes after April 19. Waiting until April 19 leaves about a one-in-ten chance of a later frost.
Nearby and next
- New York climateThe statewide normals and every place in the state
- Setauket, NY5 miles from this station, 53.4°F a year
- Upton Cooperative - Weather Office New York, NY9 miles from this station, 51.2°F a year
- Islip, NY11 miles from this station, 53.1°F a year
- Shirley, NY11 miles from this station, 52.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made