F-roads 2021–2025: share of years open by 15 June, 1 July and 15 July

The short answer: of the fourteen highland road sections in Vegagerðin's opening table, two were open by 15 June in all five years from 2021 to 2025, both of them Kjölur. Six were open by 1 July in every year. Only by 15 July were all fourteen open in all five years. Sprengisandur, both Fjallabak South sections, Landmannalaugar–Eldgjá on Fjallabak North, Emstruleið, and the Skagafjörður and Eyjafjörður routes were open by 15 June in none of the five years. The Highlands ledger starts on 10 July, and the table says that is the right side of the line for every road it uses.

#The formula

For each road section and each cut-off date: share = (number of years 2021–2025 in which the published opening date is on or before the cut-off) ÷ 5. The opening dates are Vegagerðin's "Highland Roads: opening dates" table, read 1 November 2026, which gives one date per road per year. A road counted as open by a cut-off may have closed again after a snowfall; the table does not record that, and neither can this.

#The table

Two notes on the source. Its "average opening" column for Eldgjá–Skaftártunga reads 13 May, which cannot be the mean of the five dates shown (that is about 13 June); the dates themselves are used here, not the averages. And its "earliest" for Hveravellir–Blönduvirkjun reads 1 June while the 2025 cell reads 26 May; again the cell is used. The page's one sentence of explanation is the one that matters: "The state of snow cover is the most important factor on deciding when mountain roads can be opened to traffic."

#What 2023 did to the numbers

Every road's earliest date is 2023 or 2025. Take 2023 out and the "by 1 July" column loses a year on seven roads. The 2022 column, where nothing south of Kjölur opened before 23 June, is the year to plan against.

#What it does to the Highlands ledger

The ledger uses three roads in this table: F208 north from Sigalda on Day 2, Kjölur's two sections on Days 3 and 4. Its Askja day uses F905 and F910, which are not in this table (the ledger cites the older handbook for those). For the three table roads, the latest opening in the five years is 23 June (F208 north, 2022) and 14 June (Kjölur, 2024). So the earliest start date on which all three were open in every one of the five years is 22 June, giving Day 2 on 23 June and the Kjölur days after it. The ledger's default of 10 July is eighteen days later than that, and the reason is the Askja road, not these three.

What the table would do to a ledger that started on 15 June: Day 2 at Landmannalaugar on 16 June would have found F208 north open in four years and closed in 2022; a wet year like that puts the Day 2 night at Hvolsvöllur and the Landmannalaugar day on the end of the trip or off it. A ledger that added Sprengisandur as the way north could not start before 14 July if it wanted five-for-five on this table, and that is the honest reason the ledger joins the two halves by Route 1 instead.

A share of years is a planning number for choosing a start date; the road on the day is open or closed on umferdin.is, and the table has no column for that.

#Sources

• Vegagerðin, "Opening of mountain roads", Highland Roads opening dates 2021–2025, read 1 November 2026: https://www.vegagerdin.is/en/the-transportation-system/the-road-system/roads/opening-of-mountain-roads
• The Highlands by 4x4 ledger on this site (start date 2027-07-10): /journeys/iceland-highlands-4x4-5-days
• Road status on the day: https://umferdin.is