Rochester Lake Effect Snow

Q: How much snow does Rochester get in a year?

102.0 inches per season, per NOAA NCEI's official 1991-2020 climate normals for ROCHESTER GTR INTL AP, NY US. Lake effect gradients are extreme, so nearby towns can run far higher or lower than this single station.

Q: When is lake effect snow season in Rochester?

The months with a NOAA normal of at least 1 inch at ROCHESTER GTR INTL AP, NY US run November through April, peaking in January at 27.4 inches. The lake effect core is November through February: it starts when arctic air first crosses the still-warm lake and winds down as the water cools.

Q: Where do these snowfall numbers come from?

From NOAA NCEI's 1991-2020 U.S. Climate Normals for ROCHESTER GTR INTL AP, NY US, station USW00014768, read from NCEI's public data service. They are 30 year averages, not a forecast for this winter: individual lake effect seasons swing enormously around the normal.

Why Lake Ontario buries Rochester, what NOAA's 1991-2020 normals show, and every active NWS winter product, as issued.

Season normal: 102.0 inches at ROCHESTER GTR INTL AP, NY US

Seasonal snowfall normal

102 in

Snowiest month

January

The lake

Lake Ontario

Rochester snowfall, by the numbers

NOAA NCEI normals, 1991-2020

102.0 in

seasonal normal

ROCHESTER GTR INTL AP, NY US

27.4 in

in January alone

the peak month

Nov to Apr

months with 1 in or more

the season window

Lake Ontario

the engine

NY snowbelt

Every figure is NOAA NCEI’s official 1991-2020 climate normal for the named station, ROCHESTER GTR INTL AP, NY US (USW00014768). Lake effect gradients are sharp: a few miles can change a season total by feet.

The calendar

Month by month snowfall in Rochester

NOAA’s 1991-2020 monthly snowfall normals for ROCHESTER GTR INTL AP, NY US, laid out as a snow season from July to June. Lake effect climates load their totals into the cold months when the lake is still open water; watch how fast the bars rise in November and fall off late winter.

Jul

Aug

Sep

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Monthly snowfall normals (inches), ROCHESTER GTR INTL AP, NY US, NOAA NCEI 1991-2020 U.S. Climate Normals.

Satellite view of parallel lake effect snow bands streaming southeast off all five Great Lakes — Lake effect snow bands streaming off the Great Lakes, in a NOAA satellite view. Cold air crossing warm water organizes into these parallel cloud streets, and where one comes ashore it snows hard while the next town over sees sun. “Lake effect snow bands over the Great Lakes region” — NOAA — Public domain

The mechanism

Why Rochester gets lake effect snow

Rochester sits on Lake Ontario's south shore, where west-northwest winds bring lake effect off the water and synoptic storms stack on top. Because Ontario is deep enough that it almost never freezes, the machine can run all winter, which is a big part of why Rochester perennially ranks among the snowiest large cities in America.

The physics, in the National Weather Service’s own words: “Lake Effect snow occurs when cold air, often originating from Canada, moves across the open waters of the Great Lakes... The air rises, clouds form and grow into narrow band that produces 2 to 3 inches of snow per hour or more.” And on location: “Wind direction is a key component in determining which areas will receive lake effect snow. Heavy snow may be falling in one location, while the sun may be shining just a mile or two away in either direction.” (NWS, What is Lake Effect Snow?)

Satellite view of snow covered snowbelts downwind of Lake Erie and Lake Ontario with both lakes open — Lake Erie, Lake Ontario and their snowbelts from NASA's MODIS, January 13, 2017. The white land downwind of each lake is the belt itself: snow drawn on the map by fetch and wind direction. “Lake Erie, Lake Ontario, and the Finger Lakes” — Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC — Public domain

Live, as issued

Winter weather products covering NY right now

Every active National Weather Service winter product for New York, read live from api.weather.gov and reproduced exactly as issued. Zones are larger than the city, so confirm the listed areas include yours.

Checking api.weather.gov for active winter weather products…

Why the mixed product names: for the 2017-2018 winter the NWS consolidated its lake effect products into the general winter suite. The Lake Effect Snow Warning came back on October 1, 2019, but per Service Change Notice 19-63 its use is “optional at Regional discretion” and offices may still issue Winter Storm Warnings “with the lake effect component specified in the ‘What’ section”. The old Lake Effect Snow Watch and Advisory were never reinstated. So this page passes through every winter product for the area and tags the ones whose own NWS text names lake effect.

Whiteout and travel decisions belong with the National Weather Service (weather.gov winter safety) and the New York 511 system (511 road conditions). NWS products above are reproduced as issued.

The season

When lake effect season runs, and what ends it

Lake effect season opens with the first arctic outbreaks over still-warm water, usually November, and the early-season events are often the most violent because the lake is warmest. What closes the season depends on the lake: shallow Lake Erie usually freezes and shuts its machine off, while deep Lake Ontario and Lake Superior stay mostly open and can produce all winter.

Lake Erie

80%

average annual maximum ice cover; 34 of 53 winters peaked at 90% or more. The shallowest Great Lake freezes, and its snow machine stops.

Lake Ontario

29%

average annual maximum ice cover; only 7 of 53 winters even reached 50%. The deep lake stays open, and its belt keeps running.

Our averages, computed from NOAA GLERL’s daily Great Lakes ice cover record (GLICD), ice years 1973 to 2025: for each winter we take the season’s peak daily lake-averaged ice cover, then average those peaks.

A dark wall of lake effect snow advancing across Lake Erie toward the Buffalo waterfront — The wall of snow: the leading edge of the November 2014 lake effect band advancing on Buffalo, from the NOAA Photo Library. NWS Buffalo wrote that the band edge was so sharp "many described it as a wall of snow"; every Great Lakes belt town knows a smaller version of this sky. “Snowfall descending on the Buffalo Southtowns” — NOAA Photo Library, NWS Collection — Public domain

Common questions

Rochester lake effect snow FAQ

Why does Rochester get so much snow?

How much snow does Rochester get in a year?

When is lake effect snow season in Rochester?

Is there a lake effect snow warning in Rochester right now?

The live panel on this page lists every active NWS winter product for the state, straight from api.weather.gov: Lake Effect Snow Warning, Winter Storm Warning and Watch, Winter Weather Advisory, Blizzard Warning, and Snow Squall Warning. Since the NWS product consolidation, a lake effect event may be covered under a generic winter product name, so all of them are shown and the ones whose NWS text names lake effect are tagged.

What is lake effect snow?

In the NWS's words: "Lake Effect snow occurs when cold air, often originating from Canada, moves across the open waters of the Great Lakes. As the cold air passes over the unfrozen and relatively warm waters of the Great Lakes, warmth and moisture are transferred into the lowest portion of the atmosphere. The air rises, clouds form and grow into narrow band that produces 2 to 3 inches of snow per hour or more." For Rochester, the water in question is Lake Ontario.

Where do these snowfall numbers come from?

What is the snowiest city in America?

Among large US cities the perennial contenders are Syracuse, Rochester, Buffalo and Erie. In NOAA's 1991-2020 normals used on these pages (our comparison of NCEI station figures), Syracuse's airport leads at 127.8 inches, ahead of Rochester (102.0), Erie (104.3) and Buffalo (95.4). Season by season bragging rights are tracked by the Golden Snow Globe, a privately run contest for cities over 100,000 population, and its New York sibling the Golden Snowball; both are fan projects built on NWS totals, not official NOAA rankings.

City of Buffalo boundary sign at night in wind driven lake effect snow — The city line at night during the November 2014 storm, photographed by Anthony Quintano. Inside a band, rates of 3 to 6 inches per hour with wind are what a Lake Effect Snow Warning is written for. “Historic Lake Effect Snow Hits Buffalo New York Area” by Anthony Quintano, CC BY 2.0

Elsewhere in the belts

Other snowbelt cities

New York lake effect snowThe statewide belt map this city sits inside, with records and the season shape.New York winter forecastNOAA's seasonal outlook for the whole winter, read for this state.Lake effect snow, nationwideEvery belt, the mechanism, and the Erie versus Ontario ice story.

Snowfall figures are NOAA NCEI 1991-2020 U.S. Climate Normals for ROCHESTER GTR INTL AP, NY US (public domain), refreshed with each new normals release. Alerts read live from api.weather.gov and reproduced as issued. Ice statistics computed by us from NOAA GLERL daily records and labeled as our arithmetic. No safety advice of ours appears on this page.
Hero image: “Winter Storm Knife - Town Line, NY” by Anthony Quintano, CC BY 2.0