How much rain falls around Kosiv: 30 years of downpours and what they mean for a plot

Rainfall around Kosiv is the thing sellers of mountain plots rarely mention, yet rain, more than snow, is what washes out the track to a plot, cuts gullies into a slope and floods a fresh excavation. We pulled 30 years of daily rainfall (1995-2024) for the three areas where our buyers look for land, then checked the model against a real weather station.

The figures come from the ERA5 reanalysis through Open-Meteo. ERA5 splits the map into cells of about 28 by 19 km, so Kosmach and Verkhovyna share one cell and Kosiv sits in the next one east. Treat the numbers as a way to compare places and months, not as a forecast for a particular field. Further down we show where the model goes wrong.

Which months bring the most rain to Kosiv and the hills?

June and July do. Kosiv averages 143 mm in June and 138 mm in July, three times January. With August added, the three summer months bring close to two fifths of the year's total, and they also hold most of the days when 20 mm or more falls in 24 hours.

Over the 30 years the Kosiv cell logged 169 days with at least 20 mm, five or six a year. Ninety-nine of them fell in June, July or August and another 36 in May or September. Between November and March a day like that turns up once every few years.

How much wetter the hills are than the lowland

A typical year gives Kosiv about 990 mm and the Kosmach, Verkhovyna and Vorokhta cells about 1,100 mm. The Chernivtsi cell down on the plain gets 664 mm. Even the driest of the thirty years left 718 mm on Kosiv, more than Chernivtsi sees in an ordinary one.

Read the last column like this: in a normal year the heaviest day in Kosiv drops about 42 mm. One millimetre on one square metre is one litre. A 100 m² roof therefore has to shed about 4,200 litres on that day, and a 1,000 m² plot takes roughly 42 cubic metres of water, all of it heading downhill.

July 2008, the heaviest rain in 30 years

The wettest spell in the whole record is 23-27 July 2008: 213 mm in five days over the Kosiv cell, one and a half times the July average. Radio Svoboda reported at the time that the storm began on 23 July and that by the 25th a bridge in Kosiv had been destroyed and Kolomyia was under water.

This time the model and the gauge disagree the other way: the model put more rain on Chernivtsi than the gauge caught. The model will not give you an exact figure for one village, but it gets the order of events right. Next in size over Kosiv were the five-day spells of August 2002, June 2010 and June 1998, each around 110-125 mm. Over Kosmach and Verkhovyna one of the biggest was 19-23 June 2020, at 106 mm.

For a buyer, this means a 100 mm-plus storm over a few days comes round every few years here, not once a century, and a house and its access road have to come through it without repairs. If the plot runs down to a stream, read first about the riparian buffer strip and where building is not allowed on such land.

Walking a plot to see where the water goes

Go in June or July, after two or three wet days. A dry plot in September looks equally tidy whether it washes out every summer or never does.

1. 1Stand on the top boundary and look uphillEverything above you sheds water onto you: the neighbour's vegetable patch, the road, a cleared stretch of forest. Find out where the ditch of the road above leads and whether a pipe takes water under that road.
2. 2Walk the plot from top to bottomGullies, washed-out patches, fans of sand and fine stone, lines of silt across the grass all trace the path water took in the last storm. A fresh gully after rain tells you more than anything the seller says.
3. 3Look for the wet spotsSedge, moss and grass that stays green when everything round it has dried out mark ground where water sits or comes up. That patch is not the place for the house.
4. 4Check the neighbours' foundationsDamp marks on a plinth, cracks, and retaining walls that do not appear on any plan show what the people next door have already had to fight.
5. 5Ask the seller for a video after a stormIf you cannot come in summer, ask for footage of the plot and the track to it the day after heavy rain.

Plots we currently have are in the listing of land for sale in the Carpathians, and you can call us to arrange a viewing in a wet week.

The track to the plot

An unpaved track on a slope turns into a stream bed when it has no ditch alongside. After a July downpour it can be cut so badly that an ordinary car cannot get up for weeks. Ask who tops it up with gravel and whether it has culverts. If the community does not look after it, the gravel after every storm will be your bill.

The slope above the future house

On a steep slope a 40 mm day does not soak in, it runs over the surface. That is why the cut-off ditch above the house, the drain round the footings and the roof gutters are designed together with the house. A designer sizes them for your slope and roof area. We have written separately about why foundations on a slope are the most expensive part of a mountain house.

When to schedule the groundworks

Dig in late August, September or October. In 30 years the Kosiv cell had 41 days of 20 mm-plus in June and only 9 in October. An open excavation on a slope becomes a pond after one of those days, and a washed-out foundation trench costs extra days and money.

1. Agree with the builder that excavation and footings start after mid-August, not in June.
2. Cut a temporary ditch to lead water away from the excavation before any topsoil comes off.
3. Lay crushed stone on the access before the first concrete lorry arrives.
4. Ask your insurer whether the policy covers heavy rain and flooding, since many contracts treat it as a separate risk. We went through how to read those exclusions in the article on insuring a house in the Carpathians.

What turnkey building involves is on our construction page.