Please sign in to post.
Posted by
780 posts

That's too much for me! I just double and add 30. If it's before 0, we are usually at home.

Posted by
16312 posts

I use an app.

My new smartphone displays the outside temperature in F regardless of where I am.

Posted by
4273 posts

Without reading the article, my easy way to remember is that 28C is 82F. This helps me to gage the weather. Above 28 it is hot. Below it is a little cooler.

Posted by
113 posts

For me, an easy additional reference point is body temperature: 37 degrees celsius is practically 100 degrees fahrenheit (too hot for me, if it relates to weather!!).

Posted by
2864 posts

Double it, subtract 10% (is there anything easier do in the head than double or than 10%?), and add 32.
Really simple, and if this is too much math then you didn't graduate high school.
Why was that article even written?

Posted by
1391 posts

This only works in this temp range, but 10C is 50F and 20C is roughly 70F. Obviously 0C is 32F

Posted by
4597 posts

The calculator app on my android phone has a conversion option for all metric to imperial measurements.

Posted by
5853 posts

The easiest way for me to do a quick mental conversion is that I have memorized 4 points:
0 C = 32 F (freezing)
10 C = 50 F
20 C = 68 F (room temperature)
30 C = 86 F (flip the 6 and 8 from room temp)

Posted by
5210 posts

Simply posted the link for the benefit of anyone would want to use the method of rough approximation detailed. It's very simple (similar to Laura's method), and requires no math, app, or anything - just a little memory. Everyone has their own method, and that's fine; whatever floats the boat. Personally, with seven and a half year of university training, I just do the math conversion in my head as it helps keep me mentally sharp in my so called doatage. No need for snarkiness.

Posted by
3101 posts

Multiply by 2, subtract 10%, add 32. Do it in your head. It's good to practice.

30 C - 60 F - 54 F - 86 F

40 C - 80 F - 72 F - 104 F

Posted by
2049 posts

I have to laugh because being a child of the 1970s and early 1980s, in elementary school we were taught about the metric system and Celsius conversion. Our teacher and the film we watched promised that by the advent of the 21st century, the metric system would be in use across America and we would have to know it. Of course, it never happened and non-use plus the advent of smartphones meant I've forgotten most of it.

It becomes really acute when trying recipes from outside the US and having to convert grams to cups/tsbs, etc. Thank goodness for my kitchen scale. But again, the US is behind. Maybe the US can try for the 22nd century to get in line with the world.

Posted by
19276 posts

To help the OP, I'm expanding on what Laura posted,

0° C = 32° F (freezing)
10° C = 50° F (cool day)
20° C = 68° F (room temperature)
30° C = 86° F (warm day)
40° C = 104° F (hot day).
For every °C above or below the above temperatures, you just add or subtract 1.8°F, i.e., 21°C is 69.8°F.

I would be willing to switch if we actually switched to a system that was optimized. The current SI system is not.

The meter was supposed to be 1 ten millionth of the distance from the No. Pole to the equator on the meridian that passes through Paris, the so-called "Rose line". But they missed the meter length by .22"(0.56 cm). So the meter now is just a rod of platinum-iridium in a temperature controlled room in Paris. It could just as easily been a foot long, or a yard long. Or, preferably, it should be 38.606 inches long, in which case g, or gravitational acceleration, would have been 10 m/sec².

Why would that be important? The weight of a 1 kg weight is mass x g (1 kg x 9.8m/sec²) or 9.8 Newtons (of force). Had the meter been 2% shorter, it would be easy to convert kg to Newtons, just multiply by 10, or move the decimal. Isn't that what's supposed to be so great about the metric system, that all measurements are just a multiple of ten apart?

[And yes, I know that g is not the same at every point on earth, but scientist now use the approximation of 9.8 to calculate the weight in Newtons. Rarely do they need to apply the actual value of gravitational acceleration at their location.]

Posted by
8056 posts

If it's before 0, we are usually at home.

Ha ha, mnannie! So true!

TC, thanks for the link! Very helpful!

Posted by
1742 posts

Thanks TC. That poem is perfect!

In Canada, we started converting to metric when I was in high school. We started with temperature. Since then, I basically do what mchpp does:

0=freezing
10=50
15=60
20=70
25=80
30=90
Above 30=way too friggin' hot.

It's not exact, but it's close enough for my purposes.

Like many Canadians of my vintage, I use C for ambient temperature, F for baking, inches and feet for measuring, pounds for weight, cups and tablespoons for cooking (although I can roughly convert some of those in my head), and kph for driving.

It makes no sense, I know.

Posted by
889 posts

The easy thing to do has been not to worry about conversion but to learn work & think in multiple systems.

The US has actually been a dual system since 1888, and according the the Uniform Packaging and labeling Regulation all packages of consumer products must be marked in metric units.

Posted by
3080 posts

Units Plus app (iPhone) for celsius, metric conversations and has currency conversions. Easier than doing arithmetic and don’t have to remember formulas.

Posted by
1742 posts

Tom_MN, we had temperatures with windchills in the -40s C a week ago. It was, indeed, unpleasant.

Now it's above freezing, and Monday is forecast to hit around +15C.

Posted by
5545 posts

British tabloids have a habit of sensationalism by using farenheit if the weather forecast is going to be hot and celsius when it's cold despite the UK being metric for decades, well, the majority metric. The majority of Brits weigh themselves in stones and pounds, measure their height in feet and inches and measure distances in miles unless it's athletics and then it's metres except marathons and cross country running. I just wish we'd commit 100% to metric.

Posted by
131 posts

There is a very entertaining YouTube video on this very subject. Search Nate Bargatze Saturday Night Live Skit Washington’s Dream October 28, 2023.

Posted by
19276 posts

I just wish we'd commit 100% to metric.

Including, of course, "metric" time, i.e., 10 hours/day, 100 minutes/hour, 100 seconds/minute.

As originally conceived, the "metric" system had time in units divisible by 10. Isn't that the whole idea of the metric system? But nobody liked it, so they continued to use the 24 hour, 60 minute, 60 second system.

Posted by
20301 posts

I spent 40 years talking in KIPs (K). Stiĺl does not excuse using Celcius or Centigrade or what ever they call it. By the way, there are at least 3 definitions for TON.

Posted by
19276 posts

Celcius or Centigrade or what ever they call it.

Just call it °C and be done with it.

I'm always amused when I go by a bank or somewhere that display the temperature. They might show 76°F and then change to 24.4°C. Do they really know the temperature to the nearest 0.1 °C? Can anyone really feel the difference between 24.3° and 24.4°C? (Or, for that matter, between 75°F and 76°F?)

Posted by
244 posts

I got curious why I have never had this problem and it turns out Fahrenheit is just the US and a few tiny dots on the world map, LOL. International weather sites show °C by default.

Posted by
1416 posts

Always amuses me how heated people can get about metric.

There were a LOT of objections about it being brought in here (UK) for groceries a few years ago but recent research has shown that people prefer it and have no desire to go back to pounds and ounces.

Posted by
628 posts

Celsius - Farenheit waypoints mean you can get a pretty close estimate without maths.

0 - 32
5 - 41
10 - 50
15 - 59
20 - 68
25 - 77
30 - 86
35 - 95
40 - 104

For every 5 you go up in Celsius, it's 9 in Farenheit (and obviously vice versa), so in winter, figure -5 is 23, -10 is 14, and -15 is 5. You shouldn't need even close to this many waypoints, and of course you can do the 10s (50, 68, 86) and still have a good idea.

Posted by
60 posts

I've cleaned this thread up a bit, as it was going off topic. Let's please stay on topic going forward. Thank you.