Spring Equinox

Today is the Spring/March Equinox. Officially at 2:38am on Saturday March 20, 2021 in Kelowna, this is the start of spring according to the astronomical seasons.

So what exactly happened at 2:38am?

The sun shone directly on the equator, and today is when the length of night and day are nearly equal across the globe.

What is the difference between ASTRONOMICAL and METEOROLOGICAL seasons?

Meteorological seasons are based on the annual temperature cycle, and astronomical seasons are based on the position of Earth in relation to the sun.

Start of Meteorological Seasons:
Spring: March 1
Summer: June 1
Fall: September 1
Winter: December 1

Start of Astronomical Seasons (varies by year):
Spring Equinox: March 20 to 22
Summer Solstice: June 20 to 22
Fall Equinox: September 20 to 22
Winter Solstice: December 20 to 22

Cheers to longer and warmer days ahead for us here in the Northern Hemisphere! Who’s ready for more sun?

Daylight Saving Time

Welcome to the first Monday of Daylight Saving Time… and it may be our last depending on how this year plays out with what the BC government decides to do!

A few tidbits about DST:

-Here in Canada, each province gets to decide whether to use DST. Currently out of our 13 provinces/territories, 8 observe DST, 1 doesn't observe DST, and 4 provinces partially observe DST
-BC is one of the provinces that partially observe DST - most of BC does observe daylight saving time with the exception of parts of eastern BC
-DST starts on the second Sunday in March and clocks move back by one hour on the first Sunday in November

Sidenote: DST affects my job! Every time the clock changes, it also alters when meteorologists can look up new weather information. As updated weather charts usually come out at a certain time based on the non-changing Zulu time, it generally means that I have to wait an extra hour to access information during the DST months!

What exactly does 30% chance of a shower mean?

Let’s break it down!

Three weather ideas you have to understand are:
-Forecast area
-Forecast period
-Measurable precipitation

FORECAST AREA is the region that the forecast is for. For example, if I’m producing a Kelowna forecast, then the forecast will be for Kelowna, Lake Country, West Kelowna, and Peachland. This may vary for difference forecast sources - keep in mind that forecasts do differ depending on where you get your forecast! This is very important - different meteorologists and computers may not think the same way. (Even though if we did it would make our lives much easier…)

FORECAST PERIOD is usually a 10 to 24 hour time frame. Once again, this may vary for different forecast sources.

MEASURABLE PRECIPITATION is 0.2mm of rain, or 0.2cm of snow.

The chance of precipitation is the chance that measurable precipitation will fall on anywhere within the forecast area during the forecast period.

Let’s say today’s forecast for Kelowna is a 40% chance of precipitation.

This means from 5am Thursday to 5pm, there is a 4 out of 10 chance that anywhere between Peachland and Lake Country will get at least 0.2mm of rain, or 0.2cm of snow.

Personally, I often prefer using the terms slight, moderate or high when describing precipitation risk instead of using a percentage because forecast confidence can vary depending on the weather pattern!

There are times when it’s easier to predict the weather, and then there are times when I lose sleep at night because the pattern is too complex to know exactly where the rain or snow will fall!