Campbell Valley Regional Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Campbell Valley Regional Park clear sky chart from 2005-11-05 to 2019-06-10.

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
39%
16731
9%
53787
8%
16703
41%
16703
14%
40368

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
27%
900
8%
3136
7%
896
29%
896
9%
2552
January16th to endNight
28%
910
7%
3175
7%
910
30%
910
9%
2567
February1st to 15thNight
23%
820
7%
2678
4%
820
28%
820
8%
2210
February16th to endNight
30%
736
13%
2369
8%
736
37%
736
13%
1806
March1st to 15thNight
28%
840
7%
2413
5%
840
29%
840
11%
1975
March16th to endNight
30%
896
6%
2412
3%
896
31%
896
11%
2032
April1st to 15thNight
31%
839
6%
2099
3%
839
32%
839
12%
1753
April16th to endNight
36%
590
8%
1838
7%
590
37%
590
12%
1449
May1st to 15thNight
55%
419
12%
1679
20%
419
56%
419
18%
1087
May16th to endNight
58%
438
5%
1739
10%
438
59%
438
16%
1166
June1st to 15thNight
49%
408
3%
1428
3%
408
49%
408
15%
1045
June16th to endNight
56%
390
5%
1365
3%
390
56%
390
17%
941
July1st to 15thNight
69%
370
11%
1295
12%
370
70%
370
33%
711
July16th to endNight
79%
408
16%
1469
24%
386
81%
386
42%
679
August1st to 15thNight
77%
452
18%
1596
24%
450
78%
450
40%
768
August16th to endNight
71%
673
19%
1915
17%
673
71%
673
38%
1110
September1st to 15thNight
71%
780
19%
1950
12%
780
72%
780
40%
1200
September16th to endNight
49%
776
16%
2138
13%
776
49%
776
21%
1541
October1st to 15thNight
47%
780
12%
2340
11%
780
49%
780
20%
1648
October16th to endNight
35%
832
8%
2594
8%
832
37%
832
13%
2011
November1st to 15thNight
22%
820
5%
2870
4%
820
25%
820
6%
2444
November16th to endNight
22%
840
5%
2940
4%
840
24%
840
7%
2449
December1st to 15thNight
29%
854
10%
2989
7%
854
33%
854
9%
2369
December16th to endNight
16%
960
7%
3360
3%
960
20%
960
6%
2855

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
24%7%25%5%23446%32%
54753
Night
28%7%35%423345%30%
53943
Cloud CoverDay
25%8%36%5%24345%30%
54753
Night
28%8%35%423345%29%
53946
TransparencyDay
55%7%13%15%6%1
54412
Night
57%6%12%15%7%1
53788
SeeingDay
27%5%19%25%16%4
8210
Night
33%5%13%23%19%4
16737

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
40%8%36%6%2334417%
1463
16th to endDay
38%9%26%6%3344416%
1750
February1st to 15thDay
36%9%36%5%34335%17%
1846
16th to endDay
27%11%36%5%24445%24%
1676
March1st to 15thDay
37%10%36%5%23345%17%
2204
16th to endDay
29%10%37%6%44445%19%
2516
April1st to 15thDay
29%9%36%6%35%446%19%
2509
16th to endDay
25%8%35%6%245%5%6%26%
2726
May1st to 15thDay
18%6%26%5%24446%37%
2931
16th to endDay
19%7%36%5%2445%8%32%
3073
June1st to 15thDay
23%5%26%5%3445%7%30%
3061
16th to endDay
18%7%26%5%35%45%7%34%
2925
July1st to 15thDay
11%314323447%54%
2925
16th to endDay
9%212323345%61%
2958
August1st to 15thDay
9%423312346%57%
2607
16th to endDay
12%423323446%51%
2639
September1st to 15thDay
13%6%24423236%50%
2340
16th to endDay
25%6%26%5%23446%31%
2149
October1st to 15thDay
26%6%26%433446%31%
1950
16th to endDay
34%8%36%5%23446%20%
1982
November1st to 15thDay
44%8%3343233417%
1648
16th to endDay
38%9%45%42344418%
1680
December1st to 15thDay
34%10%36%5%2333323%
1627
16th to endDay
40%13%26%5%2432315%
1568
January1st to 15thNight
42%9%2441233421%
3136
16th to endNight
37%9%35%423236%20%
3175
February1st to 15thNight
37%9%36%42333420%
2666
16th to endNight
27%9%35%5%33235%28%
2369
March1st to 15thNight
35%9%25%42434422%
2413
16th to endNight
32%10%36%5%34345%20%
2408
April1st to 15thNight
28%10%47%6%3445%5%21%
2099
16th to endNight
30%7%26%5%34345%26%
1838
May1st to 15thNight
17%435%4245%5%7%39%
1679
16th to endNight
14%6%25%5%35%6%7%7%35%
1739
June1st to 15thNight
20%6%37%5%24346%34%
1428
16th to endNight
17%5%35%5%45%5%5%5%35%
1365
July1st to 15thNight
9%3145%22235%59%
1365
16th to endNight
7%23213335%66%
1563
August1st to 15thNight
6%213213446%62%
1604
16th to endNight
7%3235%2436%8%52%
1915
September1st to 15thNight
9%213323336%59%
1950
16th to endNight
22%5%26%5%23445%37%
2138
October1st to 15thNight
22%6%2442443439%
2340
16th to endNight
34%6%24424436%26%
2594
November1st to 15thNight
43%8%25%5%2433417%
2870
16th to endNight
39%8%46%42323318%
2940
December1st to 15thNight
34%9%345%24335%22%
2989
16th to endNight
42%12%35%41322318%
3360

Percentage Cloud Cover SW (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
41%9%36%42422418%
1463
16th to endDay
38%9%26%5%2424417%
1750
February1st to 15thDay
37%9%37%5%24335%16%
1846
16th to endDay
27%12%36%6%3234424%
1676
March1st to 15thDay
37%12%36%42433416%
2204
16th to endDay
30%10%48%7%3433417%
2516
April1st to 15thDay
30%10%37%7%35%445%16%
2509
16th to endDay
25%9%47%7%3445%5%22%
2726
May1st to 15thDay
19%7%36%5%35%346%34%
2931
16th to endDay
20%8%37%6%34447%29%
3073
June1st to 15thDay
23%8%37%6%34446%26%
3061
16th to endDay
18%8%36%6%3445%6%31%
2925
July1st to 15thDay
10%415%424346%52%
2925
16th to endDay
10%313323335%59%
2958
August1st to 15thDay
10%424323347%53%
2607
16th to endDay
13%324323447%49%
2639
September1st to 15thDay
14%5%245%23235%49%
2340
16th to endDay
25%6%36%5%34346%30%
2149
October1st to 15thDay
25%8%26%423446%31%
1950
16th to endDay
36%7%35%5%23446%20%
1982
November1st to 15thDay
45%8%45%32333315%
1648
16th to endDay
39%10%35%42333418%
1680
December1st to 15thDay
35%11%36%42333323%
1627
16th to endDay
41%13%45%5%2323315%
1568
January1st to 15thNight
42%9%3441222421%
3135
16th to endNight
37%10%35%423235%20%
3175
February1st to 15thNight
37%10%36%42233420%
2666
16th to endNight
27%10%35%5%3433428%
2369
March1st to 15thNight
35%9%35%43434421%
2413
16th to endNight
32%9%47%5%34445%19%
2412
April1st to 15thNight
29%9%46%6%35%45%420%
2099
16th to endNight
29%8%26%6%34445%23%
1838
May1st to 15thNight
17%6%26%42445%7%38%
1679
16th to endNight
14%7%36%5%35%5%5%7%34%
1739
June1st to 15thNight
20%7%37%444345%32%
1428
16th to endNight
16%7%36%6%36%45%6%34%
1365
July1st to 15thNight
9%41442333458%
1365
16th to endNight
7%212213335%65%
1563
August1st to 15thNight
6%31331245%6%62%
1604
16th to endNight
7%41442446%8%52%
1915
September1st to 15thNight
9%313434345%57%
1950
16th to endNight
22%5%35%5%24335%36%
2138
October1st to 15thNight
23%6%2443443437%
2340
16th to endNight
34%6%25%423437%24%
2594
November1st to 15thNight
43%7%36%43333316%
2870
16th to endNight
40%9%46%5%2332318%
2940
December1st to 15thNight
34%10%35%42334423%
2989
16th to endNight
43%11%36%31322218%
3360

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
72%5%7%8%41
1463
16th to endDay
70%5%9%10%2
1750
February1st to 15thDay
71%5%8%6%6%1
1846
16th to endDay
62%7%9%13%42
1676
March1st to 15thDay
72%5%9%9%2
2204
16th to endDay
70%6%9%10%2
2516
April1st to 15thDay
69%8%11%9%1
2509
16th to endDay
62%8%10%11%5%
2726
May1st to 15thDay
51%8%15%17%7%
2931
16th to endDay
54%10%18%14%2
3077
June1st to 15thDay
57%8%16%12%4
3061
16th to endDay
53%8%15%16%5%
2925
July1st to 15thDay
33%7%16%26%12%3
2766
16th to endDay
27%6%18%30%13%2
2789
August1st to 15thDay
30%8%19%29%9%1
2590
16th to endDay
34%7%21%26%8%1
2639
September1st to 15thDay
37%6%15%21%16%2
2340
16th to endDay
54%8%13%15%7%1
2149
October1st to 15thDay
53%6%15%14%8%
1950
16th to endDay
63%7%12%11%4
1982
November1st to 15thDay
74%48%7%21
1648
16th to endDay
69%6%8%8%5%
1680
December1st to 15thDay
66%6%5%11%8%1
1627
16th to endDay
76%47%7%31
1568
January1st to 15thNight
68%47%12%5%
3136
16th to endNight
68%49%11%31
3175
February1st to 15thNight
68%5%9%8%42
2678
16th to endNight
60%410%16%6%2
2369
March1st to 15thNight
65%6%12%11%3
2413
16th to endNight
67%6%11%10%2
2412
April1st to 15thNight
65%7%11%11%3
2099
16th to endNight
61%7%10%13%6%
1838
May1st to 15thNight
44%7%18%18%8%1
1680
16th to endNight
46%9%23%16%4
1739
June1st to 15thNight
53%8%18%14%41
1428
16th to endNight
47%9%17%18%41
1365
July1st to 15thNight
31%5%13%30%16%3
1295
16th to endNight
20%5%16%33%18%3
1469
August1st to 15thNight
22%6%21%31%14%3
1596
16th to endNight
28%7%21%27%11%2
1915
September1st to 15thNight
28%8%17%23%19%3
1950
16th to endNight
48%7%13%20%8%1
2138
October1st to 15thNight
50%5%14%19%10%
2340
16th to endNight
61%6%14%12%5%
2594
November1st to 15thNight
73%5%9%7%21
2870
16th to endNight
70%5%8%7%6%
2940
December1st to 15thNight
64%6%9%11%7%1
2989
16th to endNight
73%46%8%41
3360

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
30%8%15%13%20%12%
120
16th to endDay
50%11%10%13%12%1
139
February1st to 15thDay
45%6%20%16%8%2
326
16th to endDay
36%9%25%16%10%1
296
March1st to 15thDay
44%8%18%17%9%1
390
16th to endDay
39%7%19%20%10%1
416
April1st to 15thDay
37%9%24%16%10%1
389
16th to endDay
29%8%24%22%10%3
378
May1st to 15thDay
21%425%27%16%3
408
16th to endDay
21%7%18%27%19%5%
468
June1st to 15thDay
22%5%25%28%14%2
616
16th to endDay
18%8%23%32%15%2
570
July1st to 15thDay
12%418%39%20%4
550
16th to endDay
7%218%38%25%6%
467
August1st to 15thDay
13%14%33%25%12%
359
16th to endDay
12%315%32%28%7%
396
September1st to 15thDay
20%418%28%21%5%
375
16th to endDay
27%217%28%18%6%
375
October1st to 15thDay
32%321%23%16%2
375
16th to endDay
39%5%13%18%15%7%
309
November1st to 15thDay
55%10%15%12%5%1
120
16th to endDay
48%217%10%10%10%
120
December1st to 15thDay
43%415%9%17%10%
120
16th to endDay
53%7%15%16%6%
128
January1st to 15thNight
45%8%12%17%13%1
900
16th to endNight
43%7%12%21%13%
910
February1st to 15thNight
44%8%16%21%8%1
824
16th to endNight
33%8%20%24%12%1
736
March1st to 15thNight
40%6%17%19%13%1
840
16th to endNight
39%416%24%12%2
896
April1st to 15thNight
34%6%17%25%14%2
839
16th to endNight
35%414%26%16%2
590
May1st to 15thNight
21%210%31%29%4
420
16th to endNight
20%18%29%33%6%
439
June1st to 15thNight
22%5%11%26%27%6%
408
16th to endNight
18%212%32%30%3
390
July1st to 15thNight
10%37%28%43%6%
370
16th to endNight
7%16%24%48%10%
408
August1st to 15thNight
10%1419%48%16%
452
16th to endNight
10%26%23%44%11%
673
September1st to 15thNight
12%17%30%36%11%
780
16th to endNight
28%211%25%26%6%
776
October1st to 15thNight
27%214%29%21%3
780
16th to endNight
38%414%22%15%4
832
November1st to 15thNight
48%6%16%21%5%
820
16th to endNight
45%8%14%16%11%3
840
December1st to 15thNight
41%7%16%22%12%1
854
16th to endNight
49%9%19%17%4
960
Page generated at 2019-06-10 16:29:48. Version ac04

Copyright 2019 A. Danko


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