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Amboy Crater
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Amboy Crater clear sky chart from 2005-11-05 to 2018-02-22.

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
78%
16662
40%
48912
33%
16624
84%
16624
67%
20860

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
74%
777
35%
2522
33%
776
81%
776
53%
1130
January16th to endNight
71%
832
41%
2600
36%
832
81%
832
55%
1184
February1st to 15thNight
75%
760
40%
2288
36%
759
84%
759
62%
1006
February16th to endNight
67%
660
40%
1979
39%
660
75%
660
54%
931
March1st to 15thNight
68%
720
37%
2121
32%
720
79%
720
60%
936
March16th to endNight
71%
768
40%
2106
29%
768
81%
768
66%
949
April1st to 15thNight
61%
719
39%
1799
17%
719
72%
719
66%
852
April16th to endNight
65%
678
44%
1758
22%
678
77%
678
76%
757
May1st to 15thNight
72%
539
42%
1619
28%
539
79%
539
77%
607
May16th to endNight
68%
561
40%
1685
24%
561
78%
561
78%
627
June1st to 15thNight
80%
540
35%
1620
28%
540
84%
540
80%
601
June16th to endNight
86%
540
37%
1620
34%
540
87%
540
83%
604
July1st to 15thNight
93%
510
32%
1530
28%
510
93%
510
71%
628
July16th to endNight
87%
564
36%
1593
31%
531
87%
531
60%
713
August1st to 15thNight
92%
654
39%
1728
27%
651
93%
651
75%
772
August16th to endNight
92%
764
44%
1910
31%
764
92%
764
76%
883
September1st to 15thNight
90%
720
39%
1908
31%
720
92%
720
74%
866
September16th to endNight
89%
716
50%
1980
44%
716
93%
716
85%
787
October1st to 15thNight
81%
720
44%
1980
37%
720
87%
720
77%
833
October16th to endNight
84%
768
47%
2322
45%
768
90%
768
75%
895
November1st to 15thNight
81%
760
39%
2470
38%
760
90%
760
70%
947
November16th to endNight
78%
780
45%
2535
45%
780
85%
780
65%
997
December1st to 15thNight
75%
780
38%
2535
36%
780
81%
780
54%
1125
December16th to endNight
68%
832
39%
2704
36%
832
77%
832
50%
1230

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
111212235%77%
49336
Night
111112235%77%
49111
TransparencyDay
11%2412%25%43%
49031
Night
10%2412%26%43%
48917
SeeingDay
26%18%35%28%7%
6291
Night
2313%37%37%5%
16672

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
2212223237%71%
1746
16th to endDay
3112213436%68%
1974
February1st to 15thDay
211212336%73%
1901
16th to endDay
22232435%6%66%
1641
March1st to 15thDay
1112336%77%
1839
16th to endDay
1111212336%75%
2115
April1st to 15thDay
1111212236%75%
2149
16th to endDay
1125%84%
2202
May1st to 15thDay
1112484%
2331
16th to endDay
121112483%
2429
June1st to 15thDay
112486%
2340
16th to endDay
1112287%
2340
July1st to 15thDay
211212345%72%
2340
16th to endDay
211131345%7%66%
2467
August1st to 15thDay
11212336%76%
2220
16th to endDay
211212435%74%
2292
September1st to 15thDay
11113245%78%
2052
16th to endDay
11112287%
1980
October1st to 15thDay
1111122380%
1980
16th to endDay
111113483%
1897
November1st to 15thDay
11221223476%
1719
16th to endDay
111112335%76%
1755
December1st to 15thDay
322212348%67%
1755
16th to endDay
4213323235%67%
1872
January1st to 15thNight
212323346%68%
2522
16th to endNight
312223235%70%
2600
February1st to 15thNight
212112235%74%
2281
16th to endNight
3212312347%67%
1979
March1st to 15thNight
21111235%5%73%
2121
16th to endNight
111112236%76%
2106
April1st to 15thNight
11211235%77%
1799
16th to endNight
111136%82%
1758
May1st to 15thNight
11225%84%
1619
16th to endNight
1126%84%
1684
June1st to 15thNight
122385%
1620
16th to endNight
111389%
1620
July1st to 15thNight
11112246%77%
1620
16th to endNight
22222335%6%68%
1701
August1st to 15thNight
1111224479%
1737
16th to endNight
11111335%79%
1910
September1st to 15thNight
11212245%78%
1908
16th to endNight
11289%
1980
October1st to 15thNight
111123482%
1980
16th to endNight
11122384%
2322
November1st to 15thNight
1111233479%
2470
16th to endNight
21112236%76%
2535
December1st to 15thNight
212223346%69%
2535
16th to endNight
4212222346%67%
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
16%36%19%35%18%
1747
16th to endDay
16%36%19%32%21%
1974
February1st to 15thDay
13%25%18%30%30%
1901
16th to endDay
17%36%17%31%23%
1641
March1st to 15thDay
9%2417%30%35%
1839
16th to endDay
10%2418%35%28%
2115
April1st to 15thDay
12%1313%30%37%
2149
16th to endDay
5%1212%30%46%
2202
May1st to 15thDay
5%2310%27%50%
2331
16th to endDay
8%138%25%53%
2432
June1st to 15thDay
427%16%68%
2340
16th to endDay
6%127%81%
2340
July1st to 15thDay
12%247%18%55%
2201
16th to endDay
15%45%13%23%37%
2312
August1st to 15thDay
10%139%21%52%
2205
16th to endDay
13%247%20%51%
2292
September1st to 15thDay
8%25%11%20%51%
2052
16th to endDay
6%11421%64%
1980
October1st to 15thDay
9%138%25%50%
1980
16th to endDay
7%149%26%49%
1897
November1st to 15thDay
12%2315%30%34%
1719
16th to endDay
11%2416%32%32%
1755
December1st to 15thDay
16%37%22%25%24%
1755
16th to endDay
20%39%23%26%16%
1872
January1st to 15thNight
16%45%16%31%25%
2522
16th to endNight
17%25%19%25%30%
2600
February1st to 15thNight
13%25%16%28%33%
2292
16th to endNight
17%35%15%30%28%
1979
March1st to 15thNight
12%25%14%30%33%
2121
16th to endNight
10%25%16%32%32%
2106
April1st to 15thNight
9%2413%33%36%
1799
16th to endNight
5%1212%28%48%
1758
May1st to 15thNight
41410%30%48%
1620
16th to endNight
4139%32%47%
1685
June1st to 15thNight
4128%15%67%
1620
16th to endNight
5%39%79%
1620
July1st to 15thNight
9%236%18%59%
1530
16th to endNight
14%36%10%25%40%
1593
August1st to 15thNight
7%237%22%55%
1728
16th to endNight
8%238%22%55%
1910
September1st to 15thNight
8%35%10%19%52%
1908
16th to endNight
4115%20%67%
1980
October1st to 15thNight
7%137%27%51%
1980
16th to endNight
6%148%20%57%
2322
November1st to 15thNight
9%1411%33%39%
2470
16th to endNight
11%1313%31%38%
2535
December1st to 15thNight
16%36%16%27%29%
2535
16th to endNight
17%37%20%29%20%
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
11%218%40%22%2
135
16th to endDay
38%26%33%23%6%
246
February1st to 15thDay
46%24%38%19%7%
326
16th to endDay
5%15%26%32%17%1
264
March1st to 15thDay
212%24%32%24%2
270
16th to endDay
316%23%33%17%5%
288
April1st to 15thDay
7%13%30%29%13%6%
269
16th to endDay
123%30%24%15%4
270
May1st to 15thDay
28%23%36%24%5%
288
16th to endDay
17%22%41%21%4
330
June1st to 15thDay
15%21%36%30%4
315
16th to endDay
1114%34%39%9%
315
July1st to 15thDay
10%37%34%16%
305
16th to endDay
26%38%37%14%
327
August1st to 15thDay
112%41%34%8%
315
16th to endDay
27%32%42%14%
332
September1st to 15thDay
1113%42%34%6%
315
16th to endDay
25%17%33%32%8%
315
October1st to 15thDay
16%22%39%27%2
315
16th to endDay
248%33%40%9%
202
November1st to 15thDay
214%40%33%8%
135
16th to endDay
25%23%29%32%5%
135
December1st to 15thDay
28%17%33%37%1
135
16th to endDay
412%17%28%30%6%
144
January1st to 15thNight
2115%43%29%6%
780
16th to endNight
4117%42%29%4
832
February1st to 15thNight
2314%46%28%5%
764
16th to endNight
5%320%43%23%3
660
March1st to 15thNight
26%18%40%26%5%
720
16th to endNight
16%18%40%29%4
768
April1st to 15thNight
19%24%37%22%3
719
16th to endNight
8%23%37%25%3
678
May1st to 15thNight
15%18%40%31%2
540
16th to endNight
6%23%34%32%2
563
June1st to 15thNight
412%46%34%1
540
16th to endNight
10%43%41%2
540
July1st to 15thNight
1332%58%4
510
16th to endNight
3326%62%3
564
August1st to 15thNight
226%62%7%
654
16th to endNight
2120%61%13%
764
September1st to 15thNight
1330%55%8%
720
16th to endNight
116%33%48%9%
716
October1st to 15thNight
1213%40%37%4
720
16th to endNight
29%34%41%11%
768
November1st to 15thNight
12%40%39%6%
760
16th to endNight
3211%37%34%10%
780
December1st to 15thNight
3214%44%31%3
780
16th to endNight
5%416%41%26%5%
832
Page generated at 2018-02-23 08:21:28. Version ac04

Copyright 2018 A. Danko


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