Deposit
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Deposit clear sky chart from 2005-11-05 to 2017-12-02.

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
28%
15221
13%
47805
8%
15190
35%
15190
16%
34024

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
15%
720
10%
2506
5%
716
22%
716
8%
1936
January16th to endNight
13%
768
9%
2574
3%
768
21%
768
8%
1978
February1st to 15thNight
9%
704
8%
2287
2%
701
17%
701
8%
1807
February16th to endNight
15%
631
13%
1896
6%
631
24%
631
10%
1447
March1st to 15thNight
15%
720
11%
2100
4%
720
23%
720
11%
1592
March16th to endNight
20%
768
17%
2029
6%
768
28%
768
16%
1482
April1st to 15thNight
19%
718
12%
1796
3%
718
23%
718
16%
1370
April16th to endNight
26%
720
16%
1800
4%
720
33%
720
22%
1265
May1st to 15thNight
30%
418
17%
1498
11%
418
39%
418
16%
1027
May16th to endNight
40%
374
15%
1497
15%
374
47%
374
18%
945
June1st to 15thNight
41%
360
13%
1440
13%
360
49%
360
16%
929
June16th to endNight
51%
360
12%
1440
12%
360
59%
360
24%
839
July1st to 15thNight
56%
340
12%
1360
18%
340
58%
340
24%
794
July16th to endNight
56%
376
15%
1418
18%
354
59%
354
24%
814
August1st to 15thNight
54%
519
14%
1590
10%
517
58%
517
27%
1013
August16th to endNight
56%
764
19%
1910
11%
764
58%
764
32%
1263
September1st to 15thNight
45%
720
18%
1800
10%
720
48%
720
30%
1223
September16th to endNight
49%
717
24%
1944
17%
717
54%
717
30%
1244
October1st to 15thNight
36%
720
18%
2160
13%
720
44%
720
21%
1466
October16th to endNight
21%
768
13%
2369
7%
768
31%
768
14%
1713
November1st to 15thNight
25%
760
16%
2472
8%
760
36%
760
17%
1732
November16th to endNight
22%
780
15%
2685
8%
780
31%
780
13%
1895
December1st to 15thNight
15%
728
6%
2546
3%
728
20%
728
7%
2041
December16th to endNight
13%
768
7%
2688
2%
768
18%
768
6%
2209

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
17%9%47%6%3445%6%29%
48649
Night
16%9%47%5%34446%32%
47974
Cloud CoverDay
17%9%47%6%3445%6%29%
48658
Night
16%9%47%5%3445%6%32%
47980
TransparencyDay
53%5%11%18%9%1
48336
Night
51%6%12%19%10%
47805
SeeingDay
23%15%25%19%11%4
5894
Night
23%17%26%22%9%1
15222

By Month

Percentage Cloud Cover NE (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
14%11%6%16%7%35%44420%
1432
16th to endDay
11%12%7%12%10%5%445%5%19%
1649
February1st to 15thDay
15%13%7%13%8%5%5%445%17%
1575
16th to endDay
16%12%5%11%9%34446%22%
1577
March1st to 15thDay
16%14%5%8%8%33445%25%
1848
16th to endDay
16%12%5%7%5%23345%30%
2193
April1st to 15thDay
19%12%46%5%33335%31%
2152
16th to endDay
16%10%36%5%24446%36%
2160
May1st to 15thDay
20%8%36%5%34447%31%
2461
16th to endDay
18%7%36%5%36%45%7%32%
2618
June1st to 15thDay
21%6%35%5%35%5%5%7%28%
2520
16th to endDay
18%6%36%6%35%5%5%8%30%
2520
July1st to 15thDay
14%5%26%7%5%6%6%6%8%31%
2520
16th to endDay
12%5%26%5%46%5%6%8%35%
2654
August1st to 15thDay
17%6%25%6%46%46%8%30%
2346
16th to endDay
15%6%25%5%35%5%6%7%35%
2292
September1st to 15thDay
19%7%36%42445%7%34%
2160
16th to endDay
15%5%25%424446%42%
2013
October1st to 15thDay
19%9%35%5%34445%34%
1800
16th to endDay
21%13%36%434445%25%
1854
November1st to 15thDay
15%12%5%5%434445%33%
1716
16th to endDay
19%13%48%42345%5%29%
1602
December1st to 15thDay
18%15%8%9%6%24335%21%
1451
16th to endDay
18%16%10%10%5%445%5%315%
1536
January1st to 15thNight
16%11%5%12%7%35%446%21%
2506
16th to endNight
13%12%5%11%8%45%45%5%21%
2574
February1st to 15thNight
13%12%7%12%8%36%44420%
2285
16th to endNight
16%12%5%10%7%45%445%24%
1896
March1st to 15thNight
18%11%5%8%6%34435%27%
2087
16th to endNight
16%11%5%6%42345%6%32%
2029
April1st to 15thNight
20%11%36%5%24445%30%
1796
16th to endNight
18%7%25%424345%40%
1800
May1st to 15thNight
19%8%35%4345%47%34%
1498
16th to endNight
12%7%45%436%45%8%37%
1495
June1st to 15thNight
19%7%34433447%37%
1440
16th to endNight
11%324435%5%6%9%42%
1440
July1st to 15thNight
10%4145%35%5%6%9%42%
1440
16th to endNight
11%4245%345%6%9%43%
1514
August1st to 15thNight
11%5%245%346%8%7%42%
1600
16th to endNight
12%6%145%2445%8%45%
1910
September1st to 15thNight
15%6%25%423347%42%
1800
16th to endNight
14%4235%34446%46%
1944
October1st to 15thNight
19%8%26%413335%40%
2160
16th to endNight
22%10%36%5%23446%29%
2369
November1st to 15thNight
14%13%36%5%2445%6%32%
2472
16th to endNight
17%11%47%5%2445%6%30%
2685
December1st to 15thNight
20%14%7%9%7%34436%19%
2546
16th to endNight
19%12%8%11%5%35%5%45%17%
2688

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
14%12%6%15%8%35%445%20%
1432
16th to endDay
11%11%7%12%10%5%5%45%5%19%
1649
February1st to 15thDay
14%14%7%11%9%45%35%418%
1575
16th to endDay
15%13%411%9%34345%23%
1577
March1st to 15thDay
16%13%5%8%8%33445%26%
1858
16th to endDay
16%12%5%7%5%33345%31%
2192
April1st to 15thDay
19%13%46%43343432%
2152
16th to endDay
16%10%25%5%24446%36%
2160
May1st to 15thDay
20%7%36%5%34447%31%
2461
16th to endDay
17%7%26%6%35%5%5%7%31%
2618
June1st to 15thDay
21%6%36%5%35%5%5%7%28%
2520
16th to endDay
18%6%35%7%35%448%30%
2520
July1st to 15thDay
13%5%35%7%46%6%6%9%30%
2520
16th to endDay
12%5%35%6%36%5%6%9%35%
2654
August1st to 15thDay
16%7%25%6%46%5%5%8%29%
2346
16th to endDay
14%6%27%5%35%5%5%8%34%
2292
September1st to 15thDay
18%8%35%43345%7%34%
2160
16th to endDay
15%6%25%433446%42%
2013
October1st to 15thDay
20%9%36%5%33446%33%
1800
16th to endDay
22%13%27%5%3445%5%26%
1854
November1st to 15thDay
15%12%46%5%34445%34%
1716
16th to endDay
19%12%46%5%2335%5%29%
1602
December1st to 15thDay
18%16%6%9%6%3434422%
1451
16th to endDay
18%16%9%10%5%345%4416%
1536
January1st to 15thNight
17%11%5%12%7%34445%22%
2506
16th to endNight
13%12%5%11%9%46%446%22%
2574
February1st to 15thNight
13%12%6%11%9%45%445%21%
2278
16th to endNight
15%12%5%9%7%35%5%45%24%
1896
March1st to 15thNight
18%11%5%8%6%34445%27%
2100
16th to endNight
15%11%5%6%42345%7%33%
2029
April1st to 15thNight
20%10%46%5%34446%30%
1796
16th to endNight
17%8%25%423346%39%
1800
May1st to 15thNight
20%8%25%6%145%47%34%
1498
16th to endNight
11%7%35%6%35%5%5%7%37%
1495
June1st to 15thNight
18%7%35%42445%6%37%
1440
16th to endNight
12%3145%35%5%6%9%42%
1440
July1st to 15thNight
11%4235%35%5%7%8%42%
1440
16th to endNight
10%4245%35%5%6%8%43%
1514
August1st to 15thNight
11%4145%35%5%7%8%41%
1600
16th to endNight
13%5%2443435%8%44%
1910
September1st to 15thNight
16%5%25%5%3335%6%43%
1800
16th to endNight
14%4245%34447%45%
1944
October1st to 15thNight
19%8%26%423336%39%
2160
16th to endNight
21%11%36%5%23447%29%
2369
November1st to 15thNight
15%11%36%42345%7%32%
2472
16th to endNight
16%11%46%435%446%30%
2685
December1st to 15thNight
19%13%6%10%6%34445%19%
2546
16th to endNight
19%13%8%10%7%35%445%17%
2688

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
65%5%10%12%5%
1433
16th to endDay
64%411%13%5%
1649
February1st to 15thDay
67%5%7%13%6%
1577
16th to endDay
61%410%15%6%
1577
March1st to 15thDay
59%5%12%15%6%
1858
16th to endDay
55%38%16%13%1
2193
April1st to 15thDay
54%48%21%9%2
2152
16th to endDay
48%48%20%14%2
2160
May1st to 15thDay
52%5%9%21%9%1
2461
16th to endDay
51%6%12%18%11%
2622
June1st to 15thDay
52%7%12%18%9%
2520
16th to endDay
50%5%13%21%8%
2520
July1st to 15thDay
48%8%11%19%10%1
2371
16th to endDay
44%7%15%22%9%
2487
August1st to 15thDay
50%7%12%21%8%
2332
16th to endDay
45%6%10%25%11%
2292
September1st to 15thDay
48%5%10%21%12%1
2160
16th to endDay
41%5%8%24%18%1
2013
October1st to 15thDay
50%5%8%20%12%1
1800
16th to endDay
58%5%11%17%6%
1854
November1st to 15thDay
52%5%13%16%10%2
1716
16th to endDay
55%413%17%8%
1602
December1st to 15thDay
65%412%12%4
1451
16th to endDay
69%5%11%10%3
1536
January1st to 15thNight
61%6%11%12%6%1
2506
16th to endNight
62%5%11%14%6%
2574
February1st to 15thNight
63%6%11%12%5%
2287
16th to endNight
59%5%11%16%6%1
1896
March1st to 15thNight
57%5%12%16%7%
2100
16th to endNight
50%6%11%18%11%1
2029
April1st to 15thNight
54%5%9%17%11%1
1796
16th to endNight
46%49%21%16%1
1800
May1st to 15thNight
49%6%9%19%14%1
1498
16th to endNight
43%7%13%23%10%1
1497
June1st to 15thNight
47%5%12%24%9%
1440
16th to endNight
35%8%19%25%11%
1440
July1st to 15thNight
36%7%15%26%13%1
1360
16th to endNight
36%7%16%24%13%1
1418
August1st to 15thNight
36%8%16%26%9%1
1590
16th to endNight
38%6%12%27%15%
1910
September1st to 15thNight
41%5%12%25%14%
1800
16th to endNight
38%410%25%20%1
1944
October1st to 15thNight
46%5%11%21%15%1
2160
16th to endNight
53%5%14%18%8%
2369
November1st to 15thNight
49%6%11%18%11%2
2472
16th to endNight
52%5%14%18%8%
2685
December1st to 15thNight
66%5%12%11%3
2546
16th to endNight
67%7%11%11%2
2688

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
26%41%20%8%11
60
16th to endDay
25%36%26%8%3
83
February1st to 15thDay
25%42%27%4
90
16th to endDay
30%26%29%11%1
236
March1st to 15thDay
30%22%27%15%4
270
16th to endDay
26%25%23%15%5%2
288
April1st to 15thDay
32%20%24%13%7%1
270
16th to endDay
22%18%28%13%11%4
270
May1st to 15thDay
32%14%21%15%9%5%
288
16th to endDay
19%15%29%18%12%5%
331
June1st to 15thDay
22%14%23%25%11%2
315
16th to endDay
21%12%32%21%10%2
315
July1st to 15thDay
16%7%26%29%14%4
305
16th to endDay
16%5%26%29%16%5%
326
August1st to 15thDay
17%8%24%22%18%8%
313
16th to endDay
15%6%21%25%18%13%
332
September1st to 15thDay
22%9%20%18%19%10%
315
16th to endDay
15%6%24%22%14%15%
314
October1st to 15thDay
25%9%20%21%16%6%
315
16th to endDay
31%20%25%15%7%
319
November1st to 15thDay
24%17%23%21%11%
280
16th to endDay
28%25%27%13%31
132
December1st to 15thDay
31%22%25%9%9%1
63
16th to endDay
29%34%34%1
64
January1st to 15thNight
26%25%28%15%3
720
16th to endNight
25%25%30%16%1
768
February1st to 15thNight
23%25%36%13%
704
16th to endNight
28%25%28%15%2
631
March1st to 15thNight
29%25%27%16%1
720
16th to endNight
25%24%26%15%7%
768
April1st to 15thNight
27%23%27%19%2
718
16th to endNight
23%17%28%20%9%
720
May1st to 15thNight
26%9%28%25%8%
418
16th to endNight
13%8%30%34%11%1
375
June1st to 15thNight
22%8%19%36%12%
360
16th to endNight
12%427%41%14%
360
July1st to 15thNight
12%221%42%19%
340
16th to endNight
11%319%44%20%
376
August1st to 15thNight
14%421%35%22%2
519
16th to endNight
14%415%33%28%3
764
September1st to 15thNight
19%8%19%31%18%2
720
16th to endNight
15%8%20%25%23%6%
717
October1st to 15thNight
24%12%20%24%15%1
720
16th to endNight
28%16%28%20%4
768
November1st to 15thNight
21%17%31%20%7%1
760
16th to endNight
24%22%27%19%5%1
780
December1st to 15thNight
30%23%27%15%3
728
16th to endNight
29%27%26%13%2
768
Page generated at 2017-12-03 11:16:43. Version ac04

Copyright 2017 A. Danko


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