Fort MacKay/Firebag Aerodrome
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort MacKay/Firebag Aerodrome clear sky chart from 2005-11-05 to 2017-09-22.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
34%
15318
7%
46604
4%
15290
37%
15290
15%
35011

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
25%
920
5%
2951
3%
920
28%
920
10%
2359
January16th to endNight
28%
960
10%
2880
6%
960
32%
960
13%
2251
February1st to 15thNight
37%
787
8%
2523
6%
783
40%
783
14%
1880
February16th to endNight
32%
632
9%
2052
7%
632
37%
632
14%
1556
March1st to 15thNight
32%
720
12%
2139
8%
720
36%
720
16%
1593
March16th to endNight
35%
759
12%
2103
6%
759
38%
759
18%
1565
April1st to 15thNight
34%
539
10%
1639
7%
539
37%
539
17%
1177
April16th to endNight
36%
537
9%
1518
5%
537
39%
537
21%
1084
May1st to 15thNight
43%
359
2%
1260
1%
359
43%
359
20%
818
May16th to endNight
46%
374
0%
1170
0%
374
46%
374
23%
763
June1st to 15thNight
43%
360
0%
906
0%
360
43%
360
23%
656
June16th to endNight
47%
360
0%
900
0%
360
47%
360
23%
668
July1st to 15thNight
54%
340
0%
850
0%
340
54%
340
27%
597
July16th to endNight
60%
376
0%
1196
0%
354
62%
354
25%
747
August1st to 15thNight
60%
360
2%
1253
2%
358
60%
358
26%
759
August16th to endNight
45%
571
8%
1694
7%
571
47%
571
20%
1187
September1st to 15thNight
46%
540
11%
1713
8%
540
49%
540
24%
1103
September16th to endNight
36%
681
11%
1899
7%
681
41%
681
20%
1389
October1st to 15thNight
28%
660
8%
1995
4%
660
31%
660
14%
1539
October16th to endNight
22%
808
6%
2392
2%
808
25%
808
11%
1918
November1st to 15thNight
23%
875
11%
2519
5%
875
28%
875
14%
1955
November16th to endNight
22%
900
5%
2860
2%
900
25%
900
8%
2366
December1st to 15thNight
27%
908
3%
2928
2%
908
28%
908
6%
2521
December16th to endNight
32%
992
8%
3264
4%
992
37%
992
11%
2560

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
12%10%47%6%46%5%5%7%29%
48324
Night
9%10%5%8%7%46%6%6%7%27%
46738
TransparencyDay
52%8%15%17%5%
47952
Night
54%8%15%16%4
46614
SeeingDay
18%9%27%26%14%3
6787
Night
14%8%31%29%13%2
15329

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
7%15%6%12%8%47%7%7%6%16%
983
16th to endDay
412%6%10%9%5%8%7%8%5%22%
1344
February1st to 15thDay
49%49%7%6%10%8%6%7%25%
1340
16th to endDay
6%10%5%11%9%7%8%7%6%5%21%
1422
March1st to 15thDay
7%13%5%9%7%37%5%6%8%25%
1818
16th to endDay
7%11%5%7%6%36%5%5%7%32%
2120
April1st to 15thDay
10%11%48%7%45%6%5%6%29%
2308
16th to endDay
10%12%5%9%6%45%5%5%6%28%
2442
May1st to 15thDay
11%9%5%7%6%4445%6%34%
2691
16th to endDay
14%7%36%5%35%45%6%38%
2941
June1st to 15thDay
14%8%37%7%35%5%6%7%29%
3052
16th to endDay
17%8%36%6%35%5%6%7%28%
3060
July1st to 15thDay
14%6%26%6%46%5%7%8%31%
3060
16th to endDay
14%8%36%6%45%5%6%8%29%
2888
August1st to 15thDay
16%6%35%5%25%45%8%36%
2700
16th to endDay
20%7%26%5%35%5%5%7%29%
2507
September1st to 15thDay
17%9%35%5%3435%6%35%
2247
16th to endDay
15%10%47%5%35%45%7%30%
1871
October1st to 15thDay
13%15%5%8%6%3445%6%26%
1634
16th to endDay
14%16%6%8%6%33346%25%
1469
November1st to 15thDay
10%15%7%10%6%35%5%45%27%
1339
16th to endDay
9%12%6%13%11%5%7%5%46%18%
1099
December1st to 15thDay
7%12%7%12%11%7%9%6%46%12%
1029
16th to endDay
7%10%412%10%5%6%8%7%7%19%
960
January1st to 15thNight
7%10%6%11%9%5%8%8%6%6%19%
2951
16th to endNight
5%10%6%10%8%5%8%7%7%5%23%
2880
February1st to 15thNight
49%48%9%6%9%7%6%6%25%
2522
16th to endNight
310%5%12%11%5%8%5%6%6%23%
2052
March1st to 15thNight
7%13%7%9%7%35%5%6%7%26%
2139
16th to endNight
9%11%5%8%6%35%6%5%7%30%
2100
April1st to 15thNight
11%9%49%6%25%5%6%7%30%
1639
16th to endNight
8%11%5%8%6%45%45%6%33%
1518
May1st to 15thNight
12%9%5%6%5%3435%8%35%
1259
16th to endNight
12%7%25%435%6%7%6%38%
1170
June1st to 15thNight
14%7%36%6%246%8%8%31%
906
16th to endNight
16%6%247%45%6%6%8%31%
900
July1st to 15thNight
8%426%6%36%7%8%10%36%
900
16th to endNight
8%325%6%346%8%11%39%
1278
August1st to 15thNight
11%5%15%3346%7%9%41%
1260
16th to endNight
14%7%26%5%35%5%5%7%35%
1694
September1st to 15thNight
14%6%2443346%7%42%
1713
16th to endNight
17%7%25%5%35%5%7%7%32%
1899
October1st to 15thNight
16%14%48%5%35%445%27%
1995
16th to endNight
13%18%7%8%6%4435%5%22%
2392
November1st to 15thNight
10%12%6%12%7%3345%6%27%
2519
16th to endNight
9%10%6%12%12%46%6%6%5%19%
2860
December1st to 15thNight
7%13%6%10%12%7%9%8%5%7%12%
2928
16th to endNight
6%12%5%10%9%46%8%6%7%21%
3264

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
62%10%12%11%3
983
16th to endDay
59%8%12%15%3
1344
February1st to 15thDay
52%9%16%16%3
1340
16th to endDay
60%6%12%13%6%
1422
March1st to 15thDay
53%7%15%18%3
1818
16th to endDay
48%7%13%24%5%
2121
April1st to 15thDay
52%7%12%17%8%
2308
16th to endDay
54%6%9%20%9%
2442
May1st to 15thDay
49%5%11%22%10%
2691
16th to endDay
45%6%11%20%14%
2946
June1st to 15thDay
51%7%12%19%9%
3052
16th to endDay
52%8%13%16%7%
3060
July1st to 15thDay
46%10%17%18%5%
2881
16th to endDay
50%10%20%18%
2707
August1st to 15thDay
45%9%22%19%3
2682
16th to endDay
51%9%20%15%2
2507
September1st to 15thDay
48%9%21%17%3
2247
16th to endDay
51%8%18%18%3
1871
October1st to 15thDay
57%8%16%15%2
1634
16th to endDay
60%9%15%13%1
1469
November1st to 15thDay
59%7%14%16%2
1339
16th to endDay
65%10%13%7%2
1099
December1st to 15thDay
71%8%11%7%
1029
16th to endDay
59%10%14%13%2
960
January1st to 15thNight
60%10%15%11%2
2951
16th to endNight
58%8%14%12%5%
2880
February1st to 15thNight
54%8%16%15%4
2533
16th to endNight
58%6%15%13%5%
2052
March1st to 15thNight
54%7%13%20%3
2139
16th to endNight
51%7%13%21%5%
2103
April1st to 15thNight
50%7%15%15%9%1
1639
16th to endNight
49%6%10%20%12%2
1518
May1st to 15thNight
45%5%10%25%13%
1260
16th to endNight
42%7%12%16%20%
1170
June1st to 15thNight
46%8%12%23%9%
906
16th to endNight
46%10%16%18%7%
900
July1st to 15thNight
37%12%19%24%5%
850
16th to endNight
34%12%28%22%2
1196
August1st to 15thNight
36%8%27%23%4
1253
16th to endNight
44%10%20%21%3
1694
September1st to 15thNight
38%9%21%24%5%
1713
16th to endNight
48%8%17%18%5%
1899
October1st to 15thNight
57%7%15%15%3
1995
16th to endNight
63%6%17%11%1
2392
November1st to 15thNight
58%7%15%15%3
2519
16th to endNight
64%9%13%9%2
2860
December1st to 15thNight
69%10%11%7%1
2928
16th to endNight
57%10%14%15%1
3264

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
35%33%40%15%3
60
16th to endDay
12%9%43%23%9%1
64
February1st to 15thDay
11%7%26%34%19%
63
16th to endDay
17%6%30%29%13%2
81
March1st to 15thDay
21%16%37%14%9%
207
16th to endDay
16%16%35%22%7%1
288
April1st to 15thDay
18%14%38%19%7%1
269
16th to endDay
18%13%30%26%9%2
369
May1st to 15thDay
16%10%23%26%18%3
468
16th to endDay
16%9%23%32%14%4
517
June1st to 15thDay
20%10%24%28%13%2
667
16th to endDay
20%6%23%29%15%3
675
July1st to 15thDay
15%6%26%30%17%3
645
16th to endDay
17%6%23%28%18%5%
535
August1st to 15thDay
16%5%14%29%23%10%
493
16th to endDay
18%12%33%24%10%1
353
September1st to 15thDay
26%10%26%22%10%3
315
16th to endDay
22%15%30%22%8%1
269
October1st to 15thDay
16%17%30%20%12%3
90
16th to endDay
29%6%25%29%7%3
96
November1st to 15thDay
17%10%51%15%5%
79
16th to endDay
16%8%33%25%13%3
60
December1st to 15thDay
8%8%35%26%16%5%
60
16th to endDay
7%12%20%39%15%4
64
January1st to 15thNight
10%11%36%27%12%1
925
16th to endNight
10%10%40%27%9%1
960
February1st to 15thNight
8%10%31%33%12%4
791
16th to endNight
7%8%34%36%11%1
632
March1st to 15thNight
13%9%35%28%11%1
720
16th to endNight
14%9%30%28%13%2
759
April1st to 15thNight
15%9%31%28%12%1
539
16th to endNight
13%7%33%31%12%1
537
May1st to 15thNight
13%10%23%33%17%1
360
16th to endNight
15%7%23%36%13%4
375
June1st to 15thNight
16%326%34%18%1
360
16th to endNight
18%320%32%21%3
360
July1st to 15thNight
9%222%38%23%2
340
16th to endNight
9%218%37%26%5%
376
August1st to 15thNight
11%116%33%32%4
360
16th to endNight
19%326%32%17%1
571
September1st to 15thNight
18%424%30%19%3
540
16th to endNight
20%7%29%31%10%
681
October1st to 15thNight
23%9%31%20%12%1
660
16th to endNight
24%10%30%24%9%1
808
November1st to 15thNight
15%9%37%23%11%1
875
16th to endNight
14%10%38%26%9%1
900
December1st to 15thNight
12%9%34%32%10%
908
16th to endNight
11%6%34%30%13%2
992
Page generated at 2017-09-23 04:43:47. Version ac04

Copyright 2017 A. Danko


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