Temperature Blanket Planner
Set your own temperature bands and colours, and see what a year actually looks like before you buy the yarn. The planner counts the days for any year, leap years included, and turns your gauge into a finished length, a stitch count and a yarn estimate. It does not invent a single temperature.
Bands are the design decision
A temperature blanket maps each day's reading to a band, and each band to a colour. How you cut the bands decides what the finished blanket looks like far more than the palette does.
Match the bands to your climate rather than copying someone else's. A year that never drops below 50°F leaves three of those six unused, and the blanket loses the variation that makes it worth making. Look at the year's actual range first, then divide it.
Row gauge decides the length, and it will surprise you
The calendar has already fixed the row count, so the only thing left to control the length is row gauge. This catches people out constantly.
If the length alarms you, there are three fixes: work a taller stitch, put two days in one row, or switch to squares and assemble a grid instead of a strip. The planner recalculates for all of them.
What a year looks like
The shape is the point: cold at both ends, warm through the middle, and the speed of the transitions is your spring and autumn. A year in a mild maritime climate looks quite different from a continental one, which is why the bands are yours to set.
Where the temperatures come from
For a year in progress you record each day as it happens. For a past year you need a historical record, and there the source matters.
The source worth knowing about is the Open-Meteo historical weather archive: it covers 1940 onwards, is free for non-commercial use, needs no account, and gives daily highs, lows and means for a location and date range. Pull your year from there and map it against the bands you set above.
This planner does not fetch it for you. It makes no network request of any kind — everything is worked out in your browser from what you type, and nothing about your location or your year leaves the page. That is deliberate: a weather lookup would mean sending your location to a third party from a page that currently sends nothing, which is a trade worth making knowingly rather than by default.
Two things this page will not do. It will not scrape weather pages that do not offer an interface for it, and it will not invent a reading. If the archive has no data for a day, that day is reported as missing and left uncoloured — a gap you can fill from your own records or leave as part of the blanket's history. A planner that quietly guesses at February the 3rd is worse than one that admits it does not know.
Rows, double rows or squares
| Layout | What a day becomes | Suits | Watch out for |
|---|---|---|---|
| One row a day | A single row across the full width | The classic strip; simplest to keep up with | Length — a dense stitch gives a very long blanket |
| Two rows a day | Two rows, same colour | Making a fine gauge reach a usable length | Doubles the yarn as well as the length |
| One square a day | A small motif joined into a grid | Portability, and any shape you like | 365 joins, and the grid rarely divides evenly |
Two worked examples
A 2026 strip in worsted. 2026 is not a leap year, so 365 rows. At 16 rows per 4 in — 4 rows per inch — that is 91.3 in long, and at 40 in wide with 14 sts per 4 in it is 140 stitches across. The area gives roughly 1,595 yards on the same model the blanket calculator documents.
The same plan in 2028. 2028 is a leap year, so 366 rows and one extra day of whichever colour the 29th of February turns out to be. At two rows a day it becomes 732 rows and 183 in — over fifteen feet, which is the point at which most people switch to squares.
Where temperature blankets go wrong
Not checking the length before starting. By row 200 it is too late. Work the gauge first.
Bands copied from a different climate. If half your bands never appear, the blanket is a solid rectangle with a stripe in it.
Buying all the yarn on day one. You cannot know the day counts for a year that has not happened. Buy the cold and mild colours first and top up — or plan a past year, where the counts are already known.
Switching between high and low midway. The record stops meaning anything. Pick one reading and keep it.
Frequently asked questions
How many rows is a temperature blanket?
One per day, so 365 in a normal year and 366 in a leap year. The planner works the leap year out from the year you enter rather than assuming 365. Two rows a day doubles the length without adding colours, and working squares instead of rows changes the shape entirely.
How long will my temperature blanket be?
Row gauge alone decides it, because the calendar has already fixed the row count. At 365 rows a gauge of 8 rows per 4 inches gives about 182 inches, 16 rows per 4 inches gives about 91, and 24 rows per 4 inches gives about 61. Check this before you start — an over-long blanket is the most common way the project goes wrong.
What temperature ranges should I use?
Ones that suit your climate. Six evenly spaced bands is a common starting point, not a rule: if your year never drops below 50°F, three of those bands never get used and the blanket loses its variation. Look at the year's actual range first, then divide it.
Where do I get the temperature data?
For a year in progress, record it daily. For a past year, Open-Meteo's historical weather archive covers 1940 onwards, is free for non-commercial use and needs no account. This planner does not fetch it for you and makes no network request at all — it plans the bands, colours, size and yarn, and you bring the temperatures.
Should I use the high, the low or the average?
Whichever you prefer, as long as you stay consistent for the whole year. Daily highs give a warmer, more varied blanket; lows give a cooler one; the mean smooths both. The planner takes all three and applies your choice to every day.
Can I make a temperature blanket for a past year?
Yes, and it is often easier than tracking live, because the whole year is available at once. Bring the records for the year and the planner does the rest. The planner treats any year the same way and there are no separate pages per year.
Sources & further reading
- Open-Meteo historical weather archive — the historical source to pull your year from. Free for non-commercial use, no account needed.
- Crochet gauge guide — measuring the row gauge the length depends on.
- Project planning guide — running a project that lasts a year.
- Temperature blanket guide — choosing the year, the reading and the bands, worked through on a real year of daily temperatures.
The arithmetic here is calendar counting and gauge multiplication. Leap years follow the Gregorian rule — divisible by 4, except centuries not divisible by 400 — so 2000 counts and 2100 will not. Yarn estimates use the same yards-per-square-inch model the blanket size calculator documents, so the two pages agree. Temperature bands, palettes and layout are design choices, not standards, and no body publishes any.
Related tools
- Blanket size calculator — the size and yarn model this page borrows.
- Stripe pattern generator — for a stripe sequence you design rather than one the weather dictates.
- Yarn yardage calculator — yardage from your own swatch.
- Gauge swatch calculator — check the row gauge before you commit to a year.