The metric system is easy to embrace if you don't try to convert the numbers into a different standard. It really isn't necessary but we do it for the sake of familiarity and comparison.
Metric weights and measures were adopted because doing math with these values is easier as the system is based on multiples of 10, a fact which the average person can safely disregard.
We just need to remember a few key metric system values and accept these as the basis of comparison to other metric weights and measures.
Metric Temperature:
0 = 32 degrees F. Ice is made at and below this temperature. It is freezing outside, literally.
20 = 68 degrees F. Spring like temperatures. A light jacket or sweater might be necessary for some. For others, the temp at which you may legally wear shorts.
26 = 79 degrees F. You may go to the beach if you wish.
30 = 86 Degrees F. It is hot and any temp above 30 C is even hotter.
Remember these four temperature points in Celsius and you can make a judgement about the weather temperature in F without having to actually do the math to figure out the exact temperature in F most of the time.
100 C - boiling or 212 F. If the pool is 100 C, don't jump in.
Baking is a pain in the a$$ as the temp in the recipe is always in a different scale than your oven. Just ask Alexa to convert the temperature for you if you need to.
Weight:
Even fewer numbers to remember here.
454 grams = 1 lb
1000 grams (g) = 1 kilogram or about 2.2 lbs
1000 kilograms (kg) = 1 metric ton or about 2200 lbs.
That's all you need to know when it comes to weight. Except for your body weight but none of us really wants to track that so just try to keep it under 1000 Kg or around whatever metric weight makes you feel good. No need to know exactly how many pounds that is...ever.
If you need 1/2 lb of nuts for a recipe, you can easily figure out that you need about 225 grams of nuts.
Liquid:
250 milliliters (ml) = 1 cup or 8 fluid ounces
1000 ml = 1 liter aka a decent amount of beer (average small beer bottle contains 330 ml)
3.95 liters = 1 US gallon
That's all you need to know about metric liquid measures.
Distance:
15 millimeters of rain is a lot of rain. More than 15 mm of rain is even more rain, or snow, or hail etc.
30 centimeters or 300 mm = 1 foot 1 inch.
1000 cm or 3000 mm = 1 meter or 3 feet 3 inches.
1 kilometer = .6 of a mile
2 Km = a little over 1 mile
Speed:
40 km/h = the speed in residential, school and hospital zones
50 km/h = the speed on most roads in built up areas
100 km/h = the speed on most highways = 62 mph
120 km/h = as fast as most people ever need to go in a vehicle (Frank12 excepted)
55 mph = 88 km/h for our American friends as a point of reference they are familiar with.
Congratulations having memorized the above metric numbers over the next few days you have just mastered the metric system without having to convert every metric number into a different number. Just accept that when it is 30 C outside, it's time to go to the beach or your favorite air conditioned bar and consume 1 liter of beer, perhaps 250 ml of Rum (don't drive) and when hungry, enjoy your 113 g hamburger with all the fixings. If you are driving to the beach, and driving faster than 60 km/h you may want to roll the windows up a bit.
If you are shopping for ground hamburger meat you will be astonished how incredibly difficult it is to find exactly 454 g of packaged hamburger. Apparently buying exactly 454 g of meat is frowned upon even though most recipes call for a multiple of this weight.
If you just accept that below 20 C is cold, below 0C is freezing and above 30 C is hot, does it really matter exactly how hot it is in F? No, hot is hot and saying it's 32 C others know it's a little hotter than just plain hot.