Malpas Observatory West
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Malpas Observatory West clear sky chart from 2005-11-06 to 2024-01-14.

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
61%
24060
33%
74350
25%
24007
70%
24007
46%
36692

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 10thNight
51%
759
33%
2457
25%
756
65%
756
41%
1236
January11th to 20thNight
52%
736
34%
2391
28%
736
63%
736
40%
1199
January21st to endNight
47%
792
34%
2574
24%
792
61%
792
32%
1396
February1st to 10thNight
54%
720
34%
2290
24%
720
69%
720
47%
1086
February11th to 20thNight
48%
700
32%
2099
23%
700
61%
700
40%
1134
February21st to endNight
45%
592
34%
1776
26%
592
57%
592
38%
963
March1st to 10thNight
45%
720
32%
2002
19%
720
59%
720
43%
1069
March11th to 20thNight
52%
720
32%
1980
21%
720
63%
720
42%
1109
March21st to endNight
49%
792
32%
2178
16%
792
63%
792
47%
1141
April1st to 10thNight
46%
720
30%
1980
14%
720
58%
720
50%
1006
April11th to 20thNight
44%
602
37%
1795
18%
602
61%
602
46%
854
April21st to endNight
51%
540
43%
1620
23%
540
68%
540
58%
703
May1st to 10thNight
57%
540
37%
1620
24%
540
66%
540
56%
729
May11th to 20thNight
61%
531
38%
1594
26%
531
69%
531
59%
690
May21st to endNight
56%
582
34%
1746
22%
582
65%
582
58%
769
June1st to 10thNight
70%
540
34%
1620
29%
540
73%
540
63%
707
June11th to 20thNight
66%
540
35%
1620
29%
540
72%
540
69%
650
June21st to endNight
76%
540
33%
1620
28%
540
79%
540
64%
695
July1st to 10thNight
80%
525
25%
1575
23%
525
81%
525
49%
786
July11th to 20thNight
85%
522
23%
1566
20%
522
85%
522
41%
835
July21st to endNight
77%
591
19%
1674
17%
558
76%
558
31%
1022
August1st to 10thNight
83%
537
27%
1602
23%
534
83%
534
46%
827
August11th to 20thNight
82%
534
31%
1602
25%
534
83%
534
45%
819
August21st to endNight
82%
684
32%
1944
27%
684
82%
684
47%
1036
September1st to 10thNight
80%
720
30%
1980
24%
720
83%
720
47%
1086
September11th to 20thNight
79%
720
41%
1980
32%
720
84%
720
64%
943
September21st to endNight
72%
720
40%
1980
26%
720
80%
720
61%
922
October1st to 10thNight
61%
720
33%
2009
19%
720
71%
720
50%
1030
October11th to 20thNight
70%
720
41%
2160
32%
720
79%
720
63%
951
October21st to endNight
64%
792
44%
2376
31%
792
77%
792
60%
1035
November1st to 10thNight
63%
740
40%
2267
29%
740
75%
740
54%
1034
November11th to 20thNight
65%
760
40%
2470
33%
760
77%
760
57%
1032
November21st to endNight
55%
760
37%
2470
28%
760
68%
760
45%
1175
December1st to 10thNight
58%
760
35%
2470
29%
760
69%
760
42%
1233
December11th to 20thNight
51%
759
31%
2929
27%
758
61%
758
29%
1617
December21st to endNight
47%
830
20%
4334
22%
817
59%
817
22%
2173

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
45%245%3445%6%59%
74944
Night
342442445%6%64%
74855
TransparencyDay
25%46%16%27%21%
74671
Night
21%46%17%29%23%
74650
SeeingDay
8%14%26%29%17%5%
13828
Night
5%7%21%33%27%6%
24074

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 10thDay
37%35%5%23346%58%
1708
11th to 20thDay
36%25%5%23346%62%
1647
21st to endDay
5%8%35%42445%6%55%
1782
February1st to 10thDay
28%3442235%6%62%
1665
11th to 20thDay
38%36%5%34445%55%
1750
21st to endDay
5%9%35%423346%56%
1480
March1st to 10thDay
37%24435%6%5%7%54%
1957
11th to 20thDay
37%3442445%7%56%
1980
21st to endDay
46%235%23447%59%
2178
April1st to 10thDay
34245%345%47%60%
1980
11th to 20thDay
242332335%5%67%
2105
21st to endDay
2423424346%66%
2340
May1st to 10thDay
4324324347%64%
2340
11th to 20thDay
3214434447%63%
2301
21st to endDay
3313313245%71%
2530
June1st to 10thDay
2212413346%72%
2340
11th to 20thDay
211221322480%
2340
21st to endDay
2224424336%69%
2340
July1st to 10thDay
3326%5%36%5%6%6%54%
2340
11th to 20thDay
6%5%27%8%47%8%8%8%36%
2340
21st to endDay
7%6%39%9%5%7%8%7%9%29%
2545
August1st to 10thDay
5%426%7%47%5%6%7%46%
2328
11th to 20thDay
4436%7%5%6%6%7%7%43%
2299
21st to endDay
6%5%36%7%5%6%5%6%6%46%
2407
September1st to 10thDay
45%26%6%45%6%6%7%49%
1980
11th to 20thDay
421343445%466%
1980
21st to endDay
2213434445%67%
1980
October1st to 10thDay
431442345%6%64%
1949
11th to 20thDay
232331322477%
1800
21st to endDay
2213313336%74%
1980
November1st to 10thDay
3322223346%70%
1808
11th to 20thDay
2212324435%71%
1710
21st to endDay
47%24323245%65%
1710
December1st to 10thDay
5%5%25%32335%7%58%
1710
11th to 20thDay
46%36%7%35%47%8%46%
2169
21st to endDay
6%9%36%6%33446%50%
3146
January1st to 10thNight
35%25%43445%6%60%
2457
11th to 20thNight
46%35%323346%61%
2391
21st to endNight
49%35%423445%57%
2574
February1st to 10thNight
16%23423346%66%
2290
11th to 20thNight
35%245%34446%58%
2098
21st to endNight
310%34324447%57%
1776
March1st to 10thNight
36%2342445%7%59%
2002
11th to 20thNight
46%34434435%60%
1980
21st to endNight
25%2342445%7%61%
2178
April1st to 10thNight
3324323446%66%
1980
11th to 20thNight
3313323435%69%
1795
21st to endNight
221322335%7%72%
1620
May1st to 10thNight
121332336%5%71%
1620
11th to 20thNight
2312223336%74%
1594
21st to endNight
131332233475%
1746
June1st to 10thNight
1211322346%75%
1620
11th to 20thNight
11221223481%
1620
21st to endNight
1111323345%75%
1620
July1st to 10thNight
2213435%5%7%7%60%
1620
11th to 20thNight
2225%436%6%7%9%54%
1620
21st to endNight
3436%6%46%7%9%13%40%
1773
August1st to 10thNight
22144345%6%9%59%
1611
11th to 20thNight
2324435%5%8%12%54%
1602
21st to endNight
23245%25%5%7%7%59%
1944
September1st to 10thNight
23234345%7%7%59%
1980
11th to 20thNight
321221433476%
1980
21st to endNight
111332233476%
1980
October1st to 10thNight
3213424446%66%
2009
11th to 20thNight
221232222478%
2160
21st to endNight
2212212345%75%
2376
November1st to 10thNight
1313323345%72%
2267
11th to 20thNight
131331235%6%72%
2470
21st to endNight
35%24423446%64%
2470
December1st to 10thNight
5%6%2333445%6%60%
2470
11th to 20thNight
46%36%5%3445%8%51%
3041
21st to endNight
47%35%6%34445%53%
4521

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 10thDay
28%3419%31%15%
1709
11th to 20thDay
24%26%22%29%16%
1647
21st to endDay
31%36%17%29%15%
1782
February1st to 10thDay
24%37%17%26%23%
1665
11th to 20thDay
31%3418%23%21%
1760
21st to endDay
30%36%16%26%18%
1480
March1st to 10thDay
28%5%5%17%30%15%
1957
11th to 20thDay
28%46%18%31%12%
1980
21st to endDay
25%36%23%30%12%
2178
April1st to 10thDay
24%36%21%31%15%
1980
11th to 20thDay
19%3417%32%24%
2108
21st to endDay
20%35%18%38%16%
2340
May1st to 10thDay
22%36%17%33%19%
2340
11th to 20thDay
21%35%19%34%17%
2304
21st to endDay
18%3415%37%23%
2530
June1st to 10thDay
14%3412%32%35%
2340
11th to 20thDay
11%226%27%51%
2340
21st to endDay
18%349%27%40%
2340
July1st to 10thDay
27%6%8%11%19%28%
2276
11th to 20thDay
39%10%11%15%14%10%
2271
21st to endDay
46%11%14%13%11%5%
2404
August1st to 10thDay
34%7%10%12%18%19%
2313
11th to 20thDay
35%9%9%16%18%13%
2299
21st to endDay
35%7%8%18%24%10%
2407
September1st to 10thDay
31%7%9%13%19%20%
1980
11th to 20thDay
19%5%6%15%31%25%
1980
21st to endDay
19%4316%31%26%
1980
October1st to 10thDay
22%45%18%24%28%
1949
11th to 20thDay
15%249%34%36%
1800
21st to endDay
14%25%16%38%25%
1980
November1st to 10thDay
17%2424%32%20%
1808
11th to 20thDay
15%35%19%33%25%
1710
21st to endDay
24%2417%33%21%
1710
December1st to 10thDay
27%47%20%24%19%
1710
11th to 20thDay
35%48%20%20%13%
2168
21st to endDay
36%4419%23%13%
3146
January1st to 10thNight
25%35%21%31%15%
2457
11th to 20thNight
26%25%20%30%17%
2391
21st to endNight
31%36%14%30%17%
2574
February1st to 10thNight
20%38%19%27%23%
2290
11th to 20thNight
27%45%18%25%21%
2099
21st to endNight
28%35%16%28%20%
1776
March1st to 10thNight
25%35%18%35%13%
2002
11th to 20thNight
27%45%18%34%13%
1980
21st to endNight
23%29%24%29%14%
2178
April1st to 10thNight
19%36%20%35%17%
1980
11th to 20thNight
19%3417%34%24%
1795
21st to endNight
14%25%22%38%20%
1620
May1st to 10thNight
14%47%21%33%22%
1620
11th to 20thNight
13%36%20%38%21%
1595
21st to endNight
15%1416%38%26%
1746
June1st to 10thNight
12%3310%33%38%
1620
11th to 20thNight
9%238%26%52%
1620
21st to endNight
13%338%24%49%
1620
July1st to 10thNight
19%7%10%11%20%34%
1575
11th to 20thNight
22%9%14%21%20%13%
1566
21st to endNight
33%9%19%19%14%6%
1674
August1st to 10thNight
20%8%13%17%21%22%
1602
11th to 20thNight
21%7%14%20%19%18%
1602
21st to endNight
22%6%10%22%27%14%
1944
September1st to 10thNight
22%7%10%17%23%22%
1980
11th to 20thNight
14%35%17%33%29%
1980
21st to endNight
13%35%14%34%32%
1980
October1st to 10thNight
19%5%7%17%22%31%
2009
11th to 20thNight
13%2312%34%36%
2160
21st to endNight
13%25%16%36%29%
2376
November1st to 10thNight
17%2421%34%22%
2267
11th to 20thNight
14%35%18%32%29%
2470
21st to endNight
22%2418%29%25%
2470
December1st to 10thNight
24%36%20%24%23%
2470
11th to 20thNight
32%5%6%17%24%16%
3041
21st to endNight
32%46%17%22%19%
4521

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 10thDay
12%17%29%26%13%2
270
11th to 20thDay
10%15%30%28%12%4
249
21st to endDay
6%16%33%27%16%3
264
February1st to 10thDay
8%19%28%28%12%6%
285
11th to 20thDay
12%23%33%24%7%1
415
21st to endDay
14%26%29%22%8%1
346
March1st to 10thDay
14%25%29%23%8%
420
11th to 20thDay
14%18%29%24%12%3
420
21st to endDay
13%25%35%19%7%1
462
April1st to 10thDay
8%21%37%19%12%3
420
11th to 20thDay
13%25%35%18%8%1
412
21st to endDay
10%26%30%19%12%3
420
May1st to 10thDay
10%22%33%25%8%3
423
11th to 20thDay
8%17%32%24%15%4
448
21st to endDay
8%17%35%26%11%3
485
June1st to 10thDay
413%31%31%17%4
450
11th to 20thDay
313%31%32%16%5%
450
21st to endDay
46%32%36%18%5%
450
July1st to 10thDay
3227%36%26%6%
446
11th to 20thDay
6%213%40%28%11%
444
21st to endDay
8%29%34%33%14%
487
August1st to 10thDay
7%315%43%22%10%
447
11th to 20thDay
5%311%43%28%11%
437
21st to endDay
8%315%33%30%11%
495
September1st to 10thDay
8%5%20%33%25%9%
450
11th to 20thDay
48%28%35%19%6%
450
21st to endDay
6%10%23%32%23%6%
450
October1st to 10thDay
8%13%30%22%21%5%
419
11th to 20thDay
5%10%24%30%24%7%
270
21st to endDay
6%16%21%30%22%4
297
November1st to 10thDay
9%14%25%30%19%3
270
11th to 20thDay
411%26%30%22%6%
270
21st to endDay
12%14%21%30%18%5%
270
December1st to 10thDay
9%12%24%32%18%4
270
11th to 20thDay
5%15%30%30%17%3
270
21st to endDay
18%19%22%31%10%1
297
January1st to 10thNight
8%10%26%30%17%9%
760
11th to 20thNight
11%8%24%32%18%7%
736
21st to endNight
11%13%24%31%18%4
792
February1st to 10thNight
5%8%28%35%18%6%
720
11th to 20thNight
8%12%29%33%15%3
704
21st to endNight
11%13%29%30%15%2
592
March1st to 10thNight
8%13%30%33%14%3
720
11th to 20thNight
8%11%23%30%23%5%
720
21st to endNight
6%12%29%33%17%2
792
April1st to 10thNight
312%33%33%16%2
720
11th to 20thNight
6%15%30%31%16%2
602
21st to endNight
411%32%33%17%4
540
May1st to 10thNight
39%28%41%18%1
540
11th to 20thNight
37%25%34%27%4
531
21st to endNight
38%28%36%21%3
584
June1st to 10thNight
3419%42%29%2
540
11th to 20thNight
15%23%40%26%4
540
21st to endNight
1216%39%38%4
540
July1st to 10thNight
38%37%44%7%
525
11th to 20thNight
31227%57%11%
522
21st to endNight
31321%59%14%
591
August1st to 10thNight
4428%52%13%
537
11th to 20thNight
31427%55%10%
534
21st to endNight
31423%55%13%
684
September1st to 10thNight
426%28%48%12%
720
11th to 20thNight
3212%36%41%6%
720
21st to endNight
37%14%33%34%9%
720
October1st to 10thNight
46%23%35%28%3
720
11th to 20thNight
3320%41%26%7%
720
21st to endNight
37%21%32%26%11%
792
November1st to 10thNight
48%22%36%24%6%
740
11th to 20thNight
37%21%41%22%6%
760
21st to endNight
8%8%24%35%20%5%
760
December1st to 10thNight
8%9%21%33%24%4
760
11th to 20thNight
11%8%24%35%20%3
760
21st to endNight
11%11%24%34%15%4
836
Page generated at 2024-01-11 11:31:59. Version ac07

Copyright 2024 Attilla Danko


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