Hyampom
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hyampom clear sky chart from 2005-11-05 to

2017-09-12
.

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
55%
15071
21%
46850
19%
15034
58%
15034
29%
28842

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
45%
716
13%
2422
13%
716
48%
716
16%
1730
January16th to endNight
45%
768
20%
2496
21%
768
48%
768
20%
1695
February1st to 15thNight
41%
697
16%
2288
16%
697
44%
697
16%
1654
February16th to endNight
40%
632
15%
1975
13%
632
43%
632
17%
1436
March1st to 15thNight
38%
720
10%
1980
8%
720
40%
720
16%
1531
March16th to endNight
34%
768
12%
2112
8%
768
37%
768
17%
1589
April1st to 15thNight
34%
719
12%
1805
5%
719
37%
719
18%
1375
April16th to endNight
48%
660
18%
1740
9%
660
51%
660
32%
1111
May1st to 15thNight
56%
533
21%
1613
15%
533
62%
533
37%
901
May16th to endNight
58%
375
20%
1496
19%
374
64%
374
26%
821
June1st to 15thNight
61%
360
21%
1440
26%
360
68%
360
31%
739
June16th to endNight
72%
360
31%
1440
40%
360
79%
360
54%
548
July1st to 15thNight
88%
340
31%
1360
44%
340
90%
340
63%
472
July16th to endNight
89%
559
36%
1588
35%
526
90%
526
72%
639
August1st to 15thNight
92%
538
39%
1611
32%
535
93%
535
76%
630
August16th to endNight
86%
692
44%
1838
31%
692
88%
692
77%
804
September1st to 15thNight
84%
706
42%
1765
27%
706
87%
706
77%
804
September16th to endNight
72%
656
35%
1826
30%
656
76%
656
52%
926
October1st to 15thNight
62%
660
24%
1980
23%
660
67%
660
39%
1092
October16th to endNight
59%
704
23%
2112
24%
704
61%
704
30%
1299
November1st to 15thNight
51%
700
15%
2235
15%
700
54%
700
20%
1527
November16th to endNight
45%
720
13%
2520
14%
720
47%
720
17%
1741
December1st to 15thNight
42%
720
14%
2520
13%
720
46%
720
17%
1775
December16th to endNight
35%
768
14%
2688
14%
768
38%
768
13%
2003

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
10%6%24423346%52%
47811
Night
11%6%25%424346%47%
47034
TransparencyDay
34%49%19%20%11%
47494
Night
37%5%10%18%18%9%
46851
SeeingDay
16%14%27%25%11%4
5912
Night
15%6%17%28%25%6%
15083

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
17%11%36%5%35%34433%
1513
16th to endDay
18%11%35%423235%39%
1728
February1st to 15thDay
18%9%36%435%45%6%32%
1576
16th to endDay
16%12%47%5%2445%7%29%
1497
March1st to 15thDay
19%15%5%6%5%23446%25%
1980
16th to endDay
18%12%37%434348%28%
2112
April1st to 15thDay
16%12%37%5%35%45%7%27%
2143
16th to endDay
10%9%34413347%45%
2218
May1st to 15thDay
6%424415%45%8%51%
2334
16th to endDay
10%7%35%42335%8%44%
2615
June1st to 15thDay
7%424423347%53%
2520
16th to endDay
3112212235%71%
2520
July1st to 15thDay
111223479%
2520
16th to endDay
2111122482%
2471
August1st to 15thDay
111122384%
2340
16th to endDay
12113481%
2363
September1st to 15thDay
11111133479%
2114
16th to endDay
323322246%67%
1801
October1st to 15thDay
9%314322346%58%
1650
16th to endDay
12%5%25%43335%6%46%
1760
November1st to 15thDay
13%6%26%5%4446%9%33%
1620
16th to endDay
16%9%36%5%44246%33%
1440
December1st to 15thDay
16%9%47%5%35%46%5%30%
1440
16th to endDay
25%10%36%5%24435%26%
1536
January1st to 15thNight
15%9%47%6%35%5%5%5%31%
2422
16th to endNight
17%10%35%5%2425%6%36%
2496
February1st to 15thNight
15%11%38%6%35%446%30%
2276
16th to endNight
14%11%37%6%35%45%8%29%
1975
March1st to 15thNight
18%12%47%5%35%5%5%8%23%
1980
16th to endNight
17%11%46%6%35%45%6%29%
2112
April1st to 15thNight
11%11%48%6%35%46%8%27%
1805
16th to endNight
8%8%35%5%2435%6%47%
1740
May1st to 15thNight
5%214425%5%49%52%
1613
16th to endNight
6%6%25%334448%50%
1496
June1st to 15thNight
5%43332346%8%53%
1440
16th to endNight
4212211236%72%
1440
July1st to 15thNight
1121222380%
1440
16th to endNight
1111111383%
1695
August1st to 15thNight
111113384%
1620
16th to endNight
1222482%
1838
September1st to 15thNight
111122483%
1765
16th to endNight
3214222246%66%
1826
October1st to 15thNight
7%314413447%55%
1980
16th to endNight
10%5%35%5%2445%6%46%
2112
November1st to 15thNight
13%6%35%6%46%6%5%7%34%
2235
16th to endNight
16%8%26%5%35%45%7%33%
2520
December1st to 15thNight
21%7%47%5%33345%33%
2520
16th to endNight
22%12%36%6%345%45%26%
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
53%5%7%14%12%7%
1513
16th to endDay
49%37%12%15%11%
1728
February1st to 15thDay
51%49%16%14%2
1576
16th to endDay
53%7%12%17%7%1
1497
March1st to 15thDay
60%5%8%11%11%1
1980
16th to endDay
56%6%13%13%7%2
2112
April1st to 15thDay
55%7%10%17%8%
2143
16th to endDay
38%6%16%23%13%2
2218
May1st to 15thDay
30%6%14%28%15%4
2334
16th to endDay
38%5%12%29%12%1
2619
June1st to 15thDay
31%5%13%20%22%6%
2520
16th to endDay
16%38%25%32%12%
2520
July1st to 15thDay
9%25%23%34%24%
2371
16th to endDay
9%1313%33%37%
2315
August1st to 15thDay
7%26%24%37%22%
2324
16th to endDay
7%26%18%37%26%
2363
September1st to 15thDay
9%16%15%37%29%
2114
16th to endDay
19%39%23%27%16%
1801
October1st to 15thDay
28%5%8%26%21%10%
1650
16th to endDay
36%5%10%21%16%9%
1760
November1st to 15thDay
45%7%13%17%9%6%
1620
16th to endDay
52%49%13%12%7%
1440
December1st to 15thDay
53%5%8%14%14%3
1440
16th to endDay
60%5%7%10%12%4
1536
January1st to 15thNight
52%7%9%11%12%7%
2422
16th to endNight
48%47%14%12%11%
2496
February1st to 15thNight
54%5%8%14%13%3
2288
16th to endNight
52%7%11%19%7%1
1975
March1st to 15thNight
58%5%9%12%12%1
1980
16th to endNight
54%7%14%14%8%1
2112
April1st to 15thNight
53%7%14%14%8%1
1805
16th to endNight
37%5%19%25%11%1
1740
May1st to 15thNight
27%7%14%30%15%4
1614
16th to endNight
32%7%15%31%12%1
1496
June1st to 15thNight
28%6%15%26%19%4
1440
16th to endNight
14%28%31%31%10%
1440
July1st to 15thNight
9%2322%38%21%
1360
16th to endNight
9%1412%34%37%
1588
August1st to 15thNight
7%2426%35%23%
1611
16th to endNight
7%25%22%37%24%
1838
September1st to 15thNight
7%15%18%38%28%
1765
16th to endNight
19%37%26%24%18%
1826
October1st to 15thNight
28%411%21%24%10%
1980
16th to endNight
36%5%11%19%18%8%
2112
November1st to 15thNight
45%8%14%15%10%5%
2235
16th to endNight
50%6%9%13%13%6%
2520
December1st to 15thNight
53%48%11%17%3
2520
16th to endNight
59%5%7%9%13%4
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
37%9%25%19%7%
141
16th to endDay
29%15%20%16%13%4
256
February1st to 15thDay
27%16%24%21%9%
236
16th to endDay
31%23%20%16%6%1
223
March1st to 15thDay
34%20%23%13%43
270
16th to endDay
36%21%23%13%4
288
April1st to 15thDay
27%21%24%18%6%1
269
16th to endDay
25%25%27%16%3
270
May1st to 15thDay
15%26%29%19%7%1
288
16th to endDay
17%15%27%21%12%4
330
June1st to 15thDay
12%18%30%25%9%3
315
16th to endDay
412%38%25%14%4
315
July1st to 15thDay
26%29%36%17%7%
305
16th to endDay
16%28%40%14%8%
327
August1st to 15thDay
5%32%35%17%8%
315
16th to endDay
15%32%30%19%11%
332
September1st to 15thDay
39%24%42%14%6%
300
16th to endDay
8%9%27%34%16%3
255
October1st to 15thDay
16%11%27%25%12%7%
255
16th to endDay
19%14%26%23%13%1
272
November1st to 15thDay
13%13%26%30%13%2
166
16th to endDay
28%21%31%13%5%
60
December1st to 15thDay
38%20%25%15%1
60
16th to endDay
25%14%18%26%15%
64
January1st to 15thNight
20%6%20%30%17%5%
720
16th to endNight
22%7%18%22%19%8%
768
February1st to 15thNight
22%9%20%28%16%2
704
16th to endNight
21%10%21%27%16%2
632
March1st to 15thNight
26%12%16%23%16%4
720
16th to endNight
26%11%23%22%14%2
768
April1st to 15thNight
20%12%26%22%16%2
719
16th to endNight
14%9%23%29%18%5%
660
May1st to 15thNight
6%5%26%29%27%4
534
16th to endNight
9%5%21%30%27%4
375
June1st to 15thNight
6%423%34%28%3
360
16th to endNight
418%38%33%2
360
July1st to 15thNight
7%32%51%6%
340
16th to endNight
2427%52%11%
559
August1st to 15thNight
430%52%11%
538
16th to endNight
19%35%43%9%
692
September1st to 15thNight
1210%30%40%15%
706
16th to endNight
4314%32%33%11%
656
October1st to 15thNight
10%318%30%28%8%
660
16th to endNight
15%5%14%26%27%10%
704
November1st to 15thNight
14%5%21%34%18%6%
700
16th to endNight
20%10%18%25%20%5%
720
December1st to 15thNight
25%7%19%25%16%5%
720
16th to endNight
31%9%18%23%12%3
768
Page generated at 2017-09-13 04:39:07. Version ac04

Copyright 2017 A. Danko


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