Safe to Plant

Karaj, Alborz Province, Iran

Planting calendar for Karaj

Worked out from 30 years of daily minimum temperatures for this location — not from a zone map, and not from the nearest big city. Move the dial to change how much frost risk you are willing to carry, and every date on the page re-times itself.

Last spring frost

1 May

Frost has finished by this date in 1 year in 2.

First autumn frost

27 October

Bring tender crops in before this date.

Frost-free season

179 days

Moderate season

The average last frost. Half of all years are later than this.

Sow this week in Karaj

Windows that are open today, 6 August. The ones marked in amber are closing within a fortnight.

Opening soon

The growing year in Karaj

307 crops, timed to the dates above

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Bay
Rye
Oca

Frost risk Start indoors Autumn sowing Sow direct Plant out Plant Harvest Today

Each bar is a window, not a deadline. Tap or hover a bar for its dates, or follow a crop name for the full timing and a harvest estimate. The blue wash is the measured weekly chance of frost across the whole record. There is also a printable one-page version of this calendar for the shed wall.

The climate behind these dates

Jan Mar Apr Jul Sep Oct Dec
Chance of at least one air frost during each week of the year, measured across the full record. The flat stretch in the middle is your frost-free season.
J
F
M
A
M
J
J
A
S
O
N
D

Mean monthly temperature across the record. Months shown in blue average at least one air frost.

Hardiness zone
6b
Typical winter low
-19.5°C (-3°F)
Growing degree days
1,158 base 10°C
Soil workable from
22 Apr
Soil warm from
5 Jun

Full frost table for Karaj →

Printable one-page calendar →

Questions about frost in Karaj

When is the last frost in Karaj?

The median last spring frost in Karaj falls on 1 May. In one year in ten frost continues as late as 17 May, so if you cannot protect tender plants, 17 May is the safer date to work to.

When is the first frost in Karaj?

The median first autumn frost in Karaj falls on 27 October, though in one year in ten it arrives by 9 October. Tender crops should be harvested before that earlier date.

How long is the growing season in Karaj?

About 179 frost-free days on a median year - moderate by world standards. Taking the cautious view at both ends, plan for roughly 145 dependable days.

What hardiness zone is Karaj in?

Karaj sits in USDA-equivalent zone 6b, based on a mean annual extreme minimum of -19.5°C (-3°F). Perennials rated to this zone or lower should survive an average winter here.

Can I trust these dates exactly?

They are statistics, not forecasts. They describe what happened across 30 years of records at this location and say nothing about this particular spring. Frost is also intensely local: a low-lying or exposed garden can run a week behind the figures on this page.