Tucker Creek Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tucker Creek Observatory clear sky chart from 2005-11-05 to 2018-04-23.

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
38%
16665
23%
49522
13%
16618
47%
16618
28%
30674

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
20%
975
21%
2674
6%
970
32%
970
21%
1759
January16th to endNight
20%
1040
24%
2704
7%
1040
31%
1040
26%
1766
February1st to 15thNight
18%
871
18%
2399
5%
868
28%
868
20%
1640
February16th to endNight
19%
683
21%
2049
6%
683
30%
683
20%
1339
March1st to 15thNight
17%
715
19%
2275
7%
715
28%
715
19%
1514
March16th to endNight
27%
624
15%
2197
10%
624
36%
624
18%
1473
April1st to 15thNight
27%
584
23%
1947
11%
584
45%
584
25%
1152
April16th to endNight
35%
558
21%
1858
14%
558
47%
558
25%
1156
May1st to 15thNight
35%
540
17%
1718
9%
539
45%
539
26%
1090
May16th to endNight
46%
563
19%
1502
12%
561
51%
561
28%
1007
June1st to 15thNight
61%
540
22%
1440
15%
540
66%
540
39%
866
June16th to endNight
65%
540
25%
1440
17%
540
70%
540
45%
819
July1st to 15thNight
68%
510
18%
1360
15%
510
70%
510
39%
808
July16th to endNight
72%
564
22%
1518
20%
531
75%
531
41%
858
August1st to 15thNight
74%
539
23%
1708
27%
536
76%
536
41%
907
August16th to endNight
71%
573
25%
1910
28%
573
74%
573
35%
1038
September1st to 15thNight
62%
540
26%
1800
25%
540
67%
540
31%
1032
September16th to endNight
60%
669
32%
1932
23%
669
66%
669
36%
1128
October1st to 15thNight
48%
720
30%
2142
20%
720
56%
720
37%
1218
October16th to endNight
34%
768
30%
2307
17%
768
48%
768
32%
1346
November1st to 15thNight
38%
760
28%
2471
18%
760
52%
760
31%
1371
November16th to endNight
31%
780
26%
2535
18%
780
42%
780
25%
1546
December1st to 15thNight
24%
969
18%
2724
7%
969
35%
969
23%
1837
December16th to endNight
19%
1040
20%
2912
5%
1040
32%
1040
20%
2004

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%6%25%5%3445%7%42%
49993
Night
12%6%24424446%46%
49707
TransparencyDay
39%5%11%23%15%2
49681
Night
37%5%11%24%18%3
49524
SeeingDay
15%9%25%26%17%6%
6499
Night
16%11%29%26%14%1
16665

By Month

Percentage Cloud Cover SE (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
16%8%35%433325%43%
1593
16th to endDay
11%7%26%5%24336%45%
1872
February1st to 15thDay
14%9%36%5%24336%40%
1790
16th to endDay
14%9%36%5%3346%6%37%
1710
March1st to 15thDay
17%7%35%424435%41%
2025
16th to endDay
18%9%46%5%34445%31%
2375
April1st to 15thDay
12%7%34423446%44%
2331
16th to endDay
19%7%35%424446%37%
2216
May1st to 15thDay
16%6%25%5%245%5%7%37%
2229
16th to endDay
11%5%35%6%36%5%47%39%
2611
June1st to 15thDay
8%425%5%35%5%6%9%44%
2520
16th to endDay
44145%35%5%7%10%46%
2520
July1st to 15thDay
9%425%5%45%5%6%9%40%
2520
16th to endDay
4315%5%37%7%9%9%41%
2543
August1st to 15thDay
8%325%446%6%6%10%39%
2241
16th to endDay
8%5%25%5%36%5%7%9%40%
2292
September1st to 15thDay
10%5%25%43445%8%44%
2160
16th to endDay
11%42432445%8%47%
2015
October1st to 15thDay
11%5%25%42445%6%48%
1816
16th to endDay
13%5%13322335%53%
1915
November1st to 15thDay
11%6%24323345%50%
1717
16th to endDay
18%7%2432333445%
1755
December1st to 15thDay
17%7%345%24246%39%
1563
16th to endDay
18%9%46%424445%36%
1664
January1st to 15thNight
16%7%34423445%42%
2674
16th to endNight
11%7%35%5%24336%45%
2704
February1st to 15thNight
15%9%46%423346%39%
2390
16th to endNight
14%6%36%424445%42%
2049
March1st to 15thNight
18%9%25%42434440%
2275
16th to endNight
19%6%37%434346%36%
2197
April1st to 15thNight
10%5%25%5%2445%7%47%
1947
16th to endNight
17%6%25%333346%44%
1858
May1st to 15thNight
15%5%245%24347%43%
1718
16th to endNight
9%5%35%5%35%5%6%7%42%
1501
June1st to 15thNight
6%314325%5%5%10%50%
1440
16th to endNight
5%2133245%6%9%54%
1440
July1st to 15thNight
6%215%42445%8%52%
1440
16th to endNight
5%4233245%8%9%50%
1623
August1st to 15thNight
5%31332446%10%54%
1718
16th to endNight
45%1442446%8%51%
1910
September1st to 15thNight
8%5%145%25%446%51%
1800
16th to endNight
9%413323446%53%
1932
October1st to 15thNight
9%414423346%55%
2142
16th to endNight
14%5%2431323454%
2307
November1st to 15thNight
10%6%13313346%53%
2471
16th to endNight
17%7%34323235%48%
2535
December1st to 15thNight
18%7%24423346%39%
2724
16th to endNight
18%9%35%413446%38%
2912

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
44%39%24%14%3
1594
16th to endDay
40%312%26%14%2
1872
February1st to 15thDay
45%412%23%12%1
1792
16th to endDay
46%411%21%12%2
1710
March1st to 15thDay
46%48%21%14%4
2025
16th to endDay
53%5%12%18%9%
2377
April1st to 15thDay
39%410%23%18%2
2331
16th to endDay
47%5%9%22%13%1
2216
May1st to 15thDay
44%6%12%21%13%
2229
16th to endDay
43%8%13%19%13%2
2615
June1st to 15thDay
34%7%14%25%16%1
2520
16th to endDay
30%7%15%24%18%3
2520
July1st to 15thDay
38%6%13%23%13%4
2371
16th to endDay
32%8%16%27%13%1
2385
August1st to 15thDay
34%9%14%24%14%1
2227
16th to endDay
35%7%16%20%16%4
2292
September1st to 15thDay
35%6%11%23%18%4
2160
16th to endDay
33%6%8%27%21%2
2015
October1st to 15thDay
35%5%10%24%20%4
1816
16th to endDay
32%46%29%21%4
1915
November1st to 15thDay
35%49%24%19%7%
1717
16th to endDay
42%37%25%19%2
1755
December1st to 15thDay
45%411%22%15%1
1563
16th to endDay
48%5%11%20%12%1
1664
January1st to 15thNight
42%49%24%17%2
2674
16th to endNight
39%311%26%16%1
2704
February1st to 15thNight
46%49%22%15%2
2399
16th to endNight
43%5%11%22%15%2
2049
March1st to 15thNight
46%48%18%16%4
2275
16th to endNight
48%412%22%10%
2197
April1st to 15thNight
34%6%11%25%18%2
1947
16th to endNight
41%39%25%17%3
1858
May1st to 15thNight
40%5%14%21%16%1
1719
16th to endNight
39%8%13%20%15%3
1503
June1st to 15thNight
28%7%12%29%19%2
1440
16th to endNight
23%7%13%28%20%6%
1440
July1st to 15thNight
29%6%15%28%13%6%
1360
16th to endNight
25%7%18%30%16%1
1518
August1st to 15thNight
23%7%15%29%21%2
1708
16th to endNight
28%6%14%24%20%5%
1910
September1st to 15thNight
32%6%8%27%19%5%
1800
16th to endNight
30%5%7%26%25%4
1932
October1st to 15thNight
30%410%23%25%6%
2142
16th to endNight
34%38%26%22%5%
2307
November1st to 15thNight
31%410%24%22%7%
2471
16th to endNight
40%37%25%21%2
2535
December1st to 15thNight
45%412%20%16%2
2724
16th to endNight
46%5%11%21%12%2
2912

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
31%16%36%13%11
135
16th to endDay
11%31%37%15%2
144
February1st to 15thDay
20%23%42%11%1
135
16th to endDay
32%24%32%6%4
120
March1st to 15thDay
31%14%41%10%1
135
16th to endDay
27%19%34%16%2
233
April1st to 15thDay
21%18%33%19%6%
330
16th to endDay
24%12%28%21%11%1
289
May1st to 15thDay
19%16%25%25%11%2
288
16th to endDay
15%7%34%25%11%5%
511
June1st to 15thDay
10%425%30%20%9%
495
16th to endDay
4431%36%18%5%
495
July1st to 15thDay
12%217%37%21%8%
475
16th to endDay
3113%33%33%13%
515
August1st to 15thDay
11%12%28%33%12%
394
16th to endDay
13%12%29%31%12%
332
September1st to 15thDay
11%5%12%26%30%14%
315
16th to endDay
12%6%16%23%27%13%
314
October1st to 15thDay
17%328%37%8%3
151
16th to endDay
14%9%36%29%9%
144
November1st to 15thDay
14%13%26%33%8%3
135
16th to endDay
30%10%35%17%5%
135
December1st to 15thDay
14%20%35%20%5%2
135
16th to endDay
25%22%44%6%
144
January1st to 15thNight
22%21%34%17%3
975
16th to endNight
17%19%40%20%2
1040
February1st to 15thNight
20%20%37%19%1
871
16th to endNight
20%19%37%20%1
683
March1st to 15thNight
24%15%39%17%2
715
16th to endNight
22%12%33%25%5%
624
April1st to 15thNight
14%18%37%24%5%
584
16th to endNight
19%11%30%26%11%
558
May1st to 15thNight
18%7%35%25%11%1
540
16th to endNight
11%331%32%18%3
563
June1st to 15thNight
7%220%40%25%2
540
16th to endNight
6%220%42%27%1
540
July1st to 15thNight
7%14%40%30%4
510
16th to endNight
6%211%32%39%8%
564
August1st to 15thNight
6%111%33%38%7%
539
16th to endNight
6%113%34%37%6%
573
September1st to 15thNight
9%315%28%35%6%
540
16th to endNight
11%5%17%25%33%6%
669
October1st to 15thNight
11%7%26%26%23%3
720
16th to endNight
17%12%33%24%11%
768
November1st to 15thNight
14%12%32%26%12%
760
16th to endNight
21%14%30%25%8%
780
December1st to 15thNight
23%14%33%21%6%
969
16th to endNight
24%15%36%20%2
1040
Page generated at 2018-04-24 09:03:01. Version ac04

Copyright 2018 A. Danko


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