Preliminary findings on number of VFR days in CYXX

[tony28898]

Hello,

This is my first post on this forum so if there is any inaccuracy please be easy on me. Advice and recommendations are always appreciated.

I hope to start getting my PPL in airports around CYXX. From my observation and research the weather in the lower mainland in winter is terrible which makes flight training difficult. To find out the best time for flight training in which consistent flying is possible (to save money), I decided to find out the VFR hours throughout the year through the METAR report in the last year. I come from a computer background and the chart below is made with the help of AI (ChatGPT/Claude), total work time is around 4 hours.

As a person who is new to aviation, the VFR hour definition below is based on what I can find on the internet and the VFR minimum. Please let me know what other considerations should be factored in to make the result more accurate.
1. Daytime
2. Visibility >= 3SM
3. Cloud base (BKN/OVC) >= 3000ft --- I just made the number up based on VFR minimum + 2000 ft. Any input is appreciated.

Data referenced :
1. Hourly METAR of CYXX in the previous year, 24*365 = 8760 entries
2. Daylight hour data of CYXX in the previous year.

Methodology:
1. Determine the cloud base based on the data in METAR
2. Combine the daylight data to filter out the non-daytime hours.
3. Extract visibility
4. Clear out some abnormal data.

Results:
The results are listed below. Each square represents one day in the month, with the leftmost square representing the first day of the month, and the rightmost square representing the last day of the month. The greener the square it is, the more flyable hours that day has. White square represent 0 flying hours available or the day doesn't exist. Refer to the legend on the right.


As I want to do my training part-time after 3 PM, I made another chart to represent the hours flyable on or after 3 PM.


Findings :
1. Obviously the number of flying days in summer is significantly more than those in winter because of the amount of daytime hours and weather.
2. Most of the days in summer are flyable, with up to 15 flyable hours in July!
3. To fly after 3 PM, the best start date is probably in April.

Limitation:
1. As a person who hasn't flown before, the definition of VFR hour is solely based on the VFR requirements. Please let me know what are the factors to be considered.
2. I also somehow find that the number of VFR hours in winter is more than I expected. This may be caused by factors that are not in the VFR criteria.
3. The result is based on METAR which is posted every xx:00. Weather can deteriorate right after the METAR is posted hence making the hour not flyable.
4. Certain limitations exist on the hours of sunrise and sunset. If the sunrise time is 6:01, the METAR posted at 6:00 will be disregarded. Same case with sunset time. I choose to disregard this because the extra hour from the sunset hour somehow offsets the error in the sunrise hour.

The chart above is produced on an experiment and is to help to determine the training schedule for myself. If there's anything you find inaccurate please do leave a comment below.

Any input is appreciated, especially on the factors that determine when can / cannot fly

[Gowyn]

Interesting and analytical approach, I commend you.

First thing I would do is contact the school you plan to use and ask for their wx minima.

VMC is just a minima and there's a big difference between 3nm vis and 15nm.

i.e. my school it ranges between 15nm vis, 3000' AGL and 5nm vis, 1500AGL, plus max wind and x-winds.

That being said all this extra data will probably give you a similar "shape" chart just less "green" if you know what I mean.

The best thing you can do though is when you do start "part time," keep going, fly as much as you can. Nothing worse than having to repeat items because you only fly once a week or worse still once a month...and get rusty.

Have fun!!!

[Big Pistons Forever]

Number of good VFR days in Abby from Nov to March ? That would be both of them.

Seriously though, I second the above post. The reality is that the lower mainland has pretty consistent low clouds and rain in the winter, so it is a struggle to train manoeuvres that require good ceilings and visibility.

Being flexible on time really helps so you can jump on good weather days, rather than having a rigid schedule. When I was instructing I always followed the weather on the bad weather days. A lot of times all the flights would be canceled in the morning but you would get a break in the weather in the late afternoon. In those cases I would phone the keener students and try to get a flight in. A lot of days we would be the only flight school airplane flying and got in a good lesson

[tony28898]

Interesting and analytical approach, I commend you.

First thing I would do is contact the school you plan to use and ask for their wx minima.

VMC is just a minima and there's a big difference between 3nm vis and 15nm.

i.e. my school it ranges between 15nm vis, 3000' AGL and 5nm vis, 1500AGL, plus max wind and x-winds.

That being said all this extra data will probably give you a similar "shape" chart just less "green" if you know what I mean.

The best thing you can do though is when you do start "part time," keep going, fly as much as you can. Nothing worse than having to repeat items because you only fly once a week or worse still once a month...and get rusty.

Have fun!!!

Thanks for the reply.
That's a good recommendation - I'll go check with the school about their wx minimas and refine the chart. I'll try running the script based on the minimas you provided tonight and see how it goes. Quite sure the whole NOV-MAR period will mostly be red I'll post the result here when I got home.

And yes, I'm aware that going part time is probably going to cost me more as I'll probably drop everything I learn between lessons if I'm not flying frequent enough. That is the main reason I'm doing the analysis to make sure I start at a time I can fly consistently I'm planning to fly 3 times a week. Myy work schedule is relatively flexible, they allow me to start working early in the morning and end early so I can have time to do some flying in the afternoon.

[tony28898]

Number of good VFR days in Abby from Nov to March ? That would be both of them.

Seriously though, I second the above post. The reality is that the lower mainland has pretty consistent low clouds and rain in the winter, so it is a struggle to train manoeuvres that require good ceilings and visibility.

Being flexible on time really helps so you can jump on good weather days, rather than having a rigid schedule. When I was instructing I always followed the weather on the bad weather days. A lot of times all the flights would be canceled in the morning but you would get a break in the weather in the late afternoon. In those cases I would phone the keener students and try to get a flight in. A lot of days we would be the only flight school airplane flying and got in a good lesson

I see. My plan is to do flying in the WFH days which im allowed to work basically everywhere, including at the airport
I'm allowed to choose WFH days in the beginning of the week, so I guess I'll choose the WFH days based on the weather forcast. If the weather doesn't work out in the morning I think I can just show up in the office and switch it to another day in the week.

Usually, how much notice are they giving before they cancel the flight? Do they tell you you can't get on the plane when you get there, or they'll tell you a few hours in advance ?

[digits_]

Wind speed might be another factor that could throw a wrench in your lesson plan. Not as problematic as the ceiling or visibility, but as a rough estimate I'd say you'd lose another 10-15% of your flying days. Often there's a work around (turning a planned solo lesson into a dual lesson), but sometimes it's just better to cancel and wait for better weather.

I like the chart and analysis though! Would it be easy to modify the algorithm for other airports? Or to add more years to the data to give a more reliable picture?