The standard understanding of the seasons isn’t so clear. What does this mean for changing your Pour Moi Day Creams?
The Seasons are Split
Pour Moi is the world’s first climate smart skincare. It has been common knowledge in the beauty industry for decades that some skincare products work best in certain conditions. This is why you load up on heavy creams in the winter and opt for a lightweight moisturizer in the summer. With two different tracks of seasons—astronomical and meteorological—how do you know when to change your Pour Moi Day Cream? The seasons you know and love—fall, winter, spring, and summer—are the
astronomical classifications based on the Earth’s position as it revolves around the sun. It takes one year for the Earth to make a full revolution. Throughout this period, the Earth experiences two solstices and two equinoxes—this is how we get our astronomical seasons. The
meteorological seasons are distinguished by the annual temperature cycle that coincides with the Gregorian calendar (aka the most widely used calendar). These groupings divide the 12-month annual calendar into 3-month seasons. The concept of warmest season, coolest season, and two transitional seasons are recycled in the meteorological classifications, but they are divided between the correlating months instead of under an umbrella label.
Astronomical: Not as Scary as it Sounds
Flashback to your Freshman Geography class where your teacher used intimidating words like “solstice” and “equinox.” In this case, all you need to know is that a
solstice is when the sun reaches its highest or lowest point, and an
equinox is when the sun crosses the equator. These solar positions affect the length of the day—the two solstices indicate the longest and shortest days of the year, and the two equinoxes mark the days in which day and night are of equal time. Coincidentally, these solar events also set off the first day of the new season. To put these not-so-scary words into application, the astronomical seasons in the Northern Hemisphere are set off around the approximate dates:
- Fall Equinox: September 22
- Winter Solstice: December 22
- Spring Equinox: March 21
- Summer Solstice: June 21
Even though these are the classifications we’re comfortable with,
it’s nearly impossible to truly define the start and finish of the changing seasons. This is because Earth revolves around in the sun in an elliptical shape—not a perfect circle—so the season lengths vary between 89 and 93 days. Therefore, the astronomical seasons aren’t accurate enough for climatologists, so the meteorological seasons were created to improve accuracy of the changing seasons in relation to the climate.
[Keep reading: Sunscreen is Not an Ingredient—It's a Step] 
Meteorological: Get to Know the “Other” Four Seasons
The meteorological seasons were born out of need for a better indication of when seasons change. The official first day of summer this year is June 20, but you might start to feel the warmth and varying humidity before or after this date. So how do the seasons based on Earth’s position link to the seasons based on temperature trends? The two seem mutually exclusive, but the overlap is surprising. Grouping the seasons based on relative temperature patterns looks like this:
- Meteorological fall: September, October, and November
- Meteorological winter: December, January, and February
- Meteorological spring: March, April, and May
- Meteorological summer: June, July, and August
We told you about the overlap, but the meteorological seasons look strikingly similar to the astronomical seasons in the Northern Hemisphere. The meteorological seasons are approximately 90 days each and they’re aligned with the monthly calendar. Having less of a variation in season start and finish dates is beneficial for agricultural, economical, and various other purposes…
including your skincare routine.
What This Means for Changing Your Pour Moi Day Creams
The 2017 Summer Solstice in the Northern Hemisphere is scheduled for June 20, but this doesn’t mean you have to wait until this date to whip out your next Pour Moi Day Cream. The summer season is when the Pour Moi
Desert and
Tropical Day Creams become the most popular because temperatures generally rise and humidity fluctuates, so rotate your products as you notice the transition in weather instead of waiting for the official astronomical announcement for summer. Using Pour Moi doesn’t mean you’re becoming an astronomer, meteorologist, or climatologist—it means you’re ready to achieve healthy, glowing skin in a matter of seconds.
