W Shaughnessy Rd
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the W Shaughnessy Rd clear sky chart from 2005-11-05 to 2018-01-12.

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
79%
16147
38%
48351
34%
16109
83%
16109
58%
22347

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
75%
762
32%
2471
35%
760
78%
760
47%
1206
January16th to endNight
71%
768
37%
2496
38%
768
77%
768
45%
1234
February1st to 15thNight
76%
700
38%
2161
38%
700
81%
700
56%
989
February16th to endNight
70%
632
36%
1892
37%
632
75%
632
46%
973
March1st to 15thNight
72%
720
41%
1980
34%
720
79%
720
62%
934
March16th to endNight
77%
768
41%
2112
32%
768
83%
768
65%
973
April1st to 15thNight
71%
719
34%
1978
24%
719
78%
719
61%
942
April16th to endNight
73%
543
47%
1686
38%
543
83%
543
76%
637
May1st to 15thNight
77%
539
39%
1619
32%
539
82%
539
70%
666
May16th to endNight
79%
561
41%
1684
32%
561
84%
561
74%
675
June1st to 15thNight
86%
540
36%
1620
32%
540
87%
540
74%
648
June16th to endNight
92%
540
35%
1620
31%
540
92%
540
76%
646
July1st to 15thNight
86%
510
26%
1530
23%
510
86%
510
51%
763
July16th to endNight
84%
564
29%
1593
24%
531
85%
531
41%
877
August1st to 15thNight
85%
539
30%
1611
26%
536
86%
536
48%
804
August16th to endNight
83%
666
34%
1884
30%
666
83%
666
45%
1028
September1st to 15thNight
81%
720
33%
1980
29%
720
83%
720
54%
1016
September16th to endNight
87%
716
45%
1980
38%
716
90%
716
72%
877
October1st to 15thNight
84%
720
41%
2052
35%
720
87%
720
69%
895
October16th to endNight
88%
768
47%
2304
43%
768
91%
768
73%
937
November1st to 15thNight
85%
760
40%
2324
40%
760
87%
760
63%
1012
November16th to endNight
78%
780
42%
2535
44%
780
82%
780
56%
1107
December1st to 15thNight
76%
780
37%
2535
39%
780
78%
780
50%
1179
December16th to endNight
73%
832
39%
2704
41%
832
76%
832
46%
1329

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
2212212346%70%
48982
Night
3212212345%69%
48549
TransparencyDay
15%2411%25%40%
48677
Night
16%2410%22%43%
48355
SeeingDay
3311%28%35%16%
5859
Night
419%40%39%4
16156

By Month

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
3213422345%64%
1710
16th to endDay
6%312222236%64%
1728
February1st to 15thDay
2323212346%67%
1697
16th to endDay
4313222346%63%
1580
March1st to 15thDay
411231334469%
1980
16th to endDay
2112213335%70%
2112
April1st to 15thDay
212213346%71%
1970
16th to endDay
11111122481%
2270
May1st to 15thDay
11111225%80%
2331
16th to endDay
2111112383%
2429
June1st to 15thDay
11111111384%
2340
16th to endDay
1111112384%
2340
July1st to 15thDay
21233235%6%8%60%
2340
16th to endDay
4325%435%5%7%10%47%
2467
August1st to 15thDay
42123235%7%9%57%
2340
16th to endDay
211232446%8%61%
2315
September1st to 15thDay
3213314346%64%
1980
16th to endDay
21111122380%
1980
October1st to 15thDay
2121223478%
1908
16th to endDay
1121123478%
1920
November1st to 15thDay
1321223476%
1863
16th to endDay
4212212235%72%
1755
December1st to 15thDay
5%313323436%62%
1755
16th to endDay
5%314323346%60%
1872
January1st to 15thNight
4313413435%63%
2471
16th to endNight
8%213322235%63%
2496
February1st to 15thNight
332212236%68%
2152
16th to endNight
5%313424336%61%
1892
March1st to 15thNight
3212213345%70%
1980
16th to endNight
212211345%73%
2112
April1st to 15thNight
2212212445%70%
1978
16th to endNight
111112384%
1686
May1st to 15thNight
11112345%77%
1619
16th to endNight
1121111285%
1684
June1st to 15thNight
111222481%
1620
16th to endNight
112112383%
1620
July1st to 15thNight
221222446%9%60%
1620
16th to endNight
3323325%6%7%12%49%
1701
August1st to 15thNight
2113325%5%7%9%56%
1620
16th to endNight
2214435%5%5%8%56%
1884
September1st to 15thNight
321332336%7%62%
1980
16th to endNight
11121222379%
1980
October1st to 15thNight
21121113478%
2052
16th to endNight
11111123480%
2304
November1st to 15thNight
122212235%74%
2324
16th to endNight
321231223472%
2535
December1st to 15thNight
5%213312345%65%
2535
16th to endNight
5%213322335%63%
2704

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
20%35%16%29%25%
1711
16th to endDay
21%2415%27%29%
1728
February1st to 15thDay
17%25%16%28%28%
1697
16th to endDay
22%2316%30%25%
1580
March1st to 15thDay
17%138%29%39%
1980
16th to endDay
16%239%33%35%
2112
April1st to 15thDay
13%127%34%39%
1970
16th to endDay
8%126%24%56%
2270
May1st to 15thDay
7%128%22%56%
2331
16th to endDay
8%116%23%58%
2432
June1st to 15thDay
8%11315%70%
2340
16th to endDay
7%11310%74%
2340
July1st to 15thDay
19%48%16%18%33%
2201
16th to endDay
28%7%12%23%18%9%
2312
August1st to 15thDay
21%5%9%16%17%29%
2325
16th to endDay
18%5%7%17%27%24%
2315
September1st to 15thDay
20%46%13%24%31%
1980
16th to endDay
10%125%25%54%
1980
October1st to 15thDay
11%228%25%49%
1908
16th to endDay
10%137%27%49%
1920
November1st to 15thDay
12%1213%31%38%
1863
16th to endDay
16%1110%29%40%
1755
December1st to 15thDay
22%35%15%27%25%
1755
16th to endDay
24%35%20%30%16%
1872
January1st to 15thNight
22%25%12%24%32%
2471
16th to endNight
24%2312%27%30%
2496
February1st to 15thNight
17%2415%23%36%
2163
16th to endNight
24%2311%25%32%
1892
March1st to 15thNight
15%138%23%47%
1980
16th to endNight
13%128%30%43%
2112
April1st to 15thNight
15%127%28%44%
1978
16th to endNight
7%16%20%63%
1686
May1st to 15thNight
9%235%23%55%
1620
16th to endNight
9%15%15%67%
1685
June1st to 15thNight
8%11312%72%
1620
16th to endNight
7%1236%78%
1620
July1st to 15thNight
19%49%16%16%33%
1530
16th to endNight
23%8%11%21%20%14%
1593
August1st to 15thNight
19%5%10%17%17%29%
1611
16th to endNight
24%5%7%13%23%26%
1884
September1st to 15thNight
19%48%16%20%31%
1980
16th to endNight
11%115%20%59%
1980
October1st to 15thNight
11%138%20%53%
2052
16th to endNight
9%138%17%59%
2304
November1st to 15thNight
13%129%27%44%
2324
16th to endNight
17%138%24%45%
2535
December1st to 15thNight
20%2414%25%32%
2535
16th to endNight
23%25%15%29%23%
2704

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
8%19%47%28%4
123
16th to endDay
4412%33%29%16%
96
February1st to 15thDay
5%7%12%29%36%8%
212
16th to endDay
7%6%21%33%25%5%
238
March1st to 15thDay
6%7%15%34%20%16%
270
16th to endDay
17%21%28%29%11%
288
April1st to 15thDay
39%20%29%27%10%
269
16th to endDay
212%24%31%20%8%
270
May1st to 15thDay
17%21%34%26%9%
288
16th to endDay
2315%37%32%9%
330
June1st to 15thDay
2211%33%34%14%
315
16th to endDay
2428%40%22%
315
July1st to 15thDay
25%22%47%21%
305
16th to endDay
3218%41%34%
327
August1st to 15thDay
3219%46%27%
315
16th to endDay
317%47%31%
332
September1st to 15thDay
5%16%25%46%14%
315
16th to endDay
3213%31%35%14%
315
October1st to 15thDay
3213%30%34%16%
243
16th to endDay
2218%54%22%
144
November1st to 15thDay
18%37%38%12%
135
16th to endDay
7%48%31%34%14%
135
December1st to 15thDay
5%26%33%42%9%
135
16th to endDay
4414%29%31%14%
144
January1st to 15thNight
5%17%50%31%3
764
16th to endNight
9%111%46%29%2
768
February1st to 15thNight
4210%49%29%3
704
16th to endNight
7%213%50%22%2
632
March1st to 15thNight
5%216%44%26%4
720
16th to endNight
2212%42%33%5%
768
April1st to 15thNight
3317%46%27%2
719
16th to endNight
2220%46%25%3
543
May1st to 15thNight
1215%44%32%3
540
16th to endNight
2114%42%38%1
563
June1st to 15thNight
118%47%38%2
540
16th to endNight
1438%52%3
540
July1st to 15thNight
2331%54%7%
510
16th to endNight
3220%60%11%
564
August1st to 15thNight
2218%64%10%
539
16th to endNight
2418%63%11%
666
September1st to 15thNight
46%26%53%8%
720
16th to endNight
26%38%45%6%
716
October1st to 15thNight
218%43%43%1
720
16th to endNight
26%37%47%6%
768
November1st to 15thNight
28%44%40%3
760
16th to endNight
5%8%43%38%3
780
December1st to 15thNight
7%17%47%33%1
780
16th to endNight
7%19%48%28%4
832
Page generated at 2018-01-12 20:01:37. Version ac04

Copyright 2018 A. Danko


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