How the Snow Score works

What the score is

The Snow Score is a number from 0 to 100 that describes how snowy a period is likely to be at a Lapland destination. It is built from past winters, not from a weather forecast: for each destination we look at 1991/92 to 2025/26 of weather-station records and ask how often the same time of year was snowy.

The formula

Snow Score = 100 × (0.5 × snow on the ground + 0.2 × deep snow + 0.1 × fresh snowfall + 0.1 × cold days + 0.1 × dry days)

How each part counts towards the Snow Score
Part	Weight	Counts as
Snow on the ground	50%	A day with at least 1 cm of snow.
Deep snow	20%	A day with at least 20 cm of snow.
Fresh snowfall	10%	At least one day with new snow (about 2 mm of water or more, or a rise in snow depth of 2 cm or more).
Cold days	10%	A day when the highest temperature stays below 0 °C.
Dry days	10%	A day without measurable rain (0.5 mm or more counts as rain).

Each part is the share of days (or, for fresh snowfall, the chance) across past winters. Small samples are smoothed slightly, so no percentage is ever exactly 0 or 100. Probabilities are shown between 3% and 97%, because a sample of winters can never prove that something is certain.

Bands and wording

The score is grouped into bands: poor from 0, fair from 35, good from 55, great from 75, excellent from 90. The bands are provisional. Words such as “very likely” follow a fixed scale: 90% or more is very likely, 66% to 90% likely, 33% to 66% about as likely as not, 10% to 33% unlikely, and below 10% very unlikely.

Range and confidence

The likely range covers the middle 8 winters in 10. Confidence is high, medium or low depending on how much the winters differ from one another and how far ahead the estimate is. A low confidence means snow depth varies a lot from winter to winter, even when snow cover is almost certain.

Where the numbers are measured

Snow depth, temperature and rain come from weather stations that can be several kilometres from resorts and slopes, not from the slopes themselves. Observations come from the weather stations of the Finnish Meteorological Institute. Where a station's record is shorter than the full period, earlier winters come from nearby stations. SMHI stations in Sweden also supply snow depth for Kemi (21 of 35 winters).

A resort can be several kilometres from its station, and slopes can hold more or less snow than the station does.

Main weather station, its distance from the resort and the winters of snow depth it supplies, for each destination
Destination	Main station	Distance	Winters of snow depth from this station
Rovaniemi	Rovaniemi Airport	9 km	35 of 35
Levi	Kittilä Pakatti	16 km	16 of 35
Ylläs	Kolari Kattilamaa	22 km	29 of 35
Saariselkä	Inari Saariselkä	1 km	35 of 35
Pyhä-Luosto	Pelkosenniemi	21 km	29 of 35
Ruka-Kuusamo	Kuusamo Kiutaköngäs	24 km	35 of 35
Kemi	Tornio Kaakkuri	23 km	14 of 35
Inari	Inari Kaamanen	28 km	16 of 35

Winters with gaps in that month's snow record are left out of the month pages' figures.

Known limits

Winters are warming, so the past is a guide, not a promise. Temperatures in older winters are adjusted for the warming trend.
Kemi lies on the coast and usually has less snow than inland destinations.
Station equipment changed over the decades, which can affect old records.
These pages describe a typical month. They are not a forecast for specific dates.

Not yet published

We have not yet published a back-test of how well the score matched real winters, and we do not yet show how forecast-based estimates compare with what happened. Until we do, treat the bands and confidence levels as provisional.

Versions

Engine 0.2.0, climatology clim-2026.0, catalogue 2026-10-07.1.

Data and licences

Weather observations: Finnish Meteorological Institute open data (Ilmatieteen laitoksen avoin data), daily weather observations, retrieved daily, modified · CC BY 4.0
Data from MET Norway (Locationforecast), modified · CC BY 4.0
SMHI open data, modified · CC BY 4.0
Image: Fintraffic / digitraffic.fi, licence CC BY 4.0
Fonts: Young Serif and Schibsted Grotesk, used under the SIL Open Font License 1.1 (licence texts).