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UpUp Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the UpUp Observatory clear sky chart from 2005-11-05 to 2017-09-24.

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
30%
14834
12%
46669
8%
14801
35%
14801
15%
33945

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
11%
778
5%
2564
2%
776
16%
776
5%
2173
January16th to endNight
19%
768
10%
2496
5%
768
25%
768
9%
2005
February1st to 15thNight
15%
701
7%
2287
3%
701
20%
701
8%
1858
February16th to endNight
21%
631
11%
2032
5%
631
28%
631
12%
1539
March1st to 15thNight
20%
720
12%
1982
5%
720
27%
720
15%
1473
March16th to endNight
30%
768
20%
2112
11%
768
37%
768
22%
1441
April1st to 15thNight
24%
718
14%
1817
6%
718
28%
718
19%
1354
April16th to endNight
32%
540
18%
1620
10%
540
39%
540
21%
1120
May1st to 15thNight
41%
465
16%
1545
13%
465
46%
465
20%
1015
May16th to endNight
41%
374
14%
1497
13%
374
49%
374
22%
849
June1st to 15thNight
40%
360
10%
1380
11%
360
46%
360
18%
869
June16th to endNight
48%
360
12%
1260
12%
360
54%
360
23%
792
July1st to 15thNight
60%
340
16%
1215
20%
340
64%
340
33%
661
July16th to endNight
52%
454
15%
1490
15%
426
55%
426
26%
891
August1st to 15thNight
60%
539
16%
1609
13%
536
62%
536
32%
970
August16th to endNight
55%
609
19%
1755
11%
609
59%
609
31%
1100
September1st to 15thNight
46%
720
15%
1810
7%
720
49%
720
30%
1220
September16th to endNight
50%
693
20%
1935
15%
693
54%
693
28%
1263
October1st to 15thNight
32%
660
15%
1980
11%
660
39%
660
18%
1409
October16th to endNight
18%
704
10%
2112
4%
704
25%
704
10%
1689
November1st to 15thNight
26%
700
15%
2419
13%
700
32%
700
14%
1732
November16th to endNight
18%
720
8%
2520
5%
720
23%
720
8%
2024
December1st to 15thNight
11%
720
4%
2520
1%
720
14%
720
5%
2170
December16th to endNight
11%
792
7%
2712
2%
792
16%
792
5%
2328

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%46%5%3445%6%32%
48240
Night
17%11%47%6%34446%30%
46838
Cloud CoverDay
17%9%46%5%3445%6%32%
48250
Night
17%11%47%6%34446%30%
46843
TransparencyDay
52%5%11%19%9%
47927
Night
54%5%11%18%9%
46669
SeeingDay
22%11%28%22%10%4
5706
Night
24%11%27%25%10%1
14841

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
21%15%5%10%7%34345%17%
1363
16th to endDay
14%18%8%11%8%3434418%
1728
February1st to 15thDay
13%16%7%14%7%45%43418%
1575
16th to endDay
15%17%7%10%6%3444421%
1440
March1st to 15thDay
15%12%46%5%45%445%30%
1966
16th to endDay
13%8%36%5%35%445%38%
2112
April1st to 15thDay
22%9%45%5%24435%32%
2140
16th to endDay
20%8%24423445%38%
2340
May1st to 15thDay
18%7%25%4345%46%35%
2403
16th to endDay
13%6%245%35%45%7%40%
2618
June1st to 15thDay
19%7%2442445%8%35%
2576
16th to endDay
15%6%25%5%35%5%6%9%35%
2700
July1st to 15thDay
12%424425%46%9%43%
2670
16th to endDay
11%5%35%5%35%5%6%8%39%
2574
August1st to 15thDay
12%6%25%43445%7%41%
2340
16th to endDay
12%5%25%6%35%46%8%39%
2435
September1st to 15thDay
17%5%35%5%2445%6%38%
2148
16th to endDay
17%5%25%5%24447%39%
1883
October1st to 15thDay
24%7%36%5%33346%31%
1650
16th to endDay
32%8%37%6%3443420%
1760
November1st to 15thDay
20%11%47%6%3445%6%24%
1439
16th to endDay
22%16%6%7%5%46%5%45%16%
1440
December1st to 15thDay
20%21%7%10%5%35%34413%
1440
16th to endDay
19%21%8%10%6%36%43413%
1500
January1st to 15thNight
21%17%7%10%8%4443315%
2564
16th to endNight
15%15%6%10%9%44445%18%
2496
February1st to 15thNight
12%18%7%12%8%4434418%
2285
16th to endNight
17%12%6%8%7%44445%25%
2032
March1st to 15thNight
17%10%5%7%6%3444431%
1970
16th to endNight
15%8%46%5%23435%40%
2112
April1st to 15thNight
22%10%46%41334433%
1817
16th to endNight
17%8%35%5%34446%36%
1620
May1st to 15thNight
19%6%25%42445%6%36%
1545
16th to endNight
12%5%244246%5%7%43%
1495
June1st to 15thNight
15%5%26%6%35%448%37%
1380
16th to endNight
12%6%25%5%35%45%8%40%
1260
July1st to 15thNight
7%42443435%8%51%
1287
16th to endNight
10%425%4346%5%8%43%
1592
August1st to 15thNight
8%425%5%35%45%8%46%
1620
16th to endNight
11%426%5%23447%47%
1755
September1st to 15thNight
15%5%25%4335%5%7%41%
1810
16th to endNight
14%5%25%5%33337%43%
1935
October1st to 15thNight
21%7%36%5%34446%32%
1980
16th to endNight
30%10%37%5%23345%23%
2112
November1st to 15thNight
18%12%46%6%33446%29%
2419
16th to endNight
23%14%5%8%6%2345%5%18%
2520
December1st to 15thNight
20%22%8%11%6%2333412%
2520
16th to endNight
22%18%8%10%6%2443413%
2712

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
20%15%6%9%8%34345%17%
1363
16th to endDay
14%18%8%11%8%34335%18%
1728
February1st to 15thDay
13%17%7%13%7%5%443418%
1575
16th to endDay
15%17%7%10%7%25%44420%
1440
March1st to 15thDay
16%12%46%6%45%445%29%
1977
16th to endDay
13%8%45%6%3445%5%38%
2111
April1st to 15thDay
22%10%35%5%24435%32%
2140
16th to endDay
20%8%2432344439%
2340
May1st to 15thDay
19%6%35%444446%35%
2403
16th to endDay
14%6%245%25%45%7%40%
2618
June1st to 15thDay
19%7%24425%46%7%35%
2576
16th to endDay
16%6%25%5%345%6%9%35%
2700
July1st to 15thDay
12%424435%45%9%42%
2670
16th to endDay
12%5%35%5%35%5%6%8%39%
2574
August1st to 15thDay
13%6%25%5%245%5%7%42%
2340
16th to endDay
13%5%25%5%35%46%8%39%
2435
September1st to 15thDay
17%5%35%5%2445%6%38%
2148
16th to endDay
18%5%25%5%2445%6%39%
1883
October1st to 15thDay
24%8%36%424446%31%
1650
16th to endDay
32%9%37%6%2443420%
1760
November1st to 15thDay
21%10%47%6%4345%6%24%
1439
16th to endDay
21%16%5%9%446%435%17%
1440
December1st to 15thDay
20%21%8%10%5%2443413%
1440
16th to endDay
19%21%8%9%6%35%44313%
1500
January1st to 15thNight
20%17%7%10%8%3443315%
2564
16th to endNight
16%15%6%10%9%44445%18%
2496
February1st to 15thNight
12%18%7%12%8%35%34418%
2278
16th to endNight
17%12%5%8%7%34445%25%
2032
March1st to 15thNight
17%11%5%7%6%3444431%
1982
16th to endNight
15%8%46%5%23435%40%
2112
April1st to 15thNight
22%9%46%41334433%
1817
16th to endNight
17%8%35%434446%36%
1620
May1st to 15thNight
19%7%25%43435%6%36%
1545
16th to endNight
12%5%234245%6%7%43%
1495
June1st to 15thNight
15%6%25%6%35%45%8%37%
1380
16th to endNight
13%6%25%435%45%8%39%
1260
July1st to 15thNight
7%4345%2346%8%51%
1287
16th to endNight
10%5%244346%5%8%44%
1592
August1st to 15thNight
8%415%5%35%45%8%46%
1620
16th to endNight
11%425%5%23446%47%
1755
September1st to 15thNight
15%5%25%42345%6%42%
1810
16th to endNight
14%5%245%33347%44%
1935
October1st to 15thNight
21%7%35%5%345%46%32%
1980
16th to endNight
30%9%38%5%23445%22%
2112
November1st to 15thNight
19%11%46%5%24446%30%
2419
16th to endNight
23%14%5%8%6%24446%18%
2520
December1st to 15thNight
20%22%8%10%6%2433412%
2520
16th to endNight
22%19%8%10%6%2443413%
2712

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
69%5%11%9%4
1364
16th to endDay
70%37%9%8%
1728
February1st to 15thDay
70%48%12%4
1577
16th to endDay
66%5%7%12%7%
1440
March1st to 15thDay
56%5%14%16%7%
1977
16th to endDay
47%5%9%18%16%3
2112
April1st to 15thDay
55%38%19%11%
2140
16th to endDay
47%48%22%14%1
2340
May1st to 15thDay
48%5%9%22%12%1
2403
16th to endDay
41%6%12%23%13%1
2622
June1st to 15thDay
46%6%11%24%10%
2576
16th to endDay
43%7%15%20%11%
2700
July1st to 15thDay
35%7%13%27%14%1
2513
16th to endDay
41%7%11%27%11%
2413
August1st to 15thDay
40%7%15%22%13%1
2327
16th to endDay
40%8%14%26%8%
2435
September1st to 15thDay
45%6%14%24%9%
2148
16th to endDay
44%6%12%28%7%
1883
October1st to 15thDay
54%5%10%19%10%
1650
16th to endDay
67%411%10%5%
1760
November1st to 15thDay
59%5%14%13%6%
1439
16th to endDay
70%411%9%21
1440
December1st to 15thDay
74%310%8%2
1440
16th to endDay
74%38%9%3
1500
January1st to 15thNight
73%49%7%3
2564
16th to endNight
67%49%11%6%
2496
February1st to 15thNight
69%49%12%3
2287
16th to endNight
60%412%16%6%
2032
March1st to 15thNight
55%413%17%8%
1982
16th to endNight
46%49%20%16%2
2112
April1st to 15thNight
54%38%19%12%1
1817
16th to endNight
48%47%18%18%2
1620
May1st to 15thNight
46%410%18%15%3
1545
16th to endNight
37%5%15%24%16%1
1497
June1st to 15thNight
44%5%11%24%13%
1380
16th to endNight
41%6%13%23%14%
1260
July1st to 15thNight
29%6%13%28%21%1
1215
16th to endNight
37%6%12%28%14%
1490
August1st to 15thNight
34%5%17%27%13%
1609
16th to endNight
36%5%15%28%13%
1755
September1st to 15thNight
40%5%16%24%11%
1810
16th to endNight
41%413%30%10%
1935
October1st to 15thNight
51%5%12%20%10%
1980
16th to endNight
63%6%10%13%5%
2112
November1st to 15thNight
54%5%13%18%7%1
2419
16th to endNight
66%6%12%12%2
2520
December1st to 15thNight
75%5%10%6%2
2520
16th to endNight
75%47%8%3
2712

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
23%18%41%13%3
60
16th to endDay
45%10%27%11%5%
96
February1st to 15thDay
33%25%34%6%
90
16th to endDay
37%17%34%11%
81
March1st to 15thDay
26%17%31%20%3
267
16th to endDay
22%12%32%20%9%1
288
April1st to 15thDay
27%14%30%17%8%1
270
16th to endDay
26%13%27%18%9%5%
270
May1st to 15thDay
29%8%26%20%9%6%
288
16th to endDay
18%15%29%22%8%4
331
June1st to 15thDay
24%11%25%27%9%1
371
16th to endDay
18%9%36%23%9%2
495
July1st to 15thDay
14%10%26%28%15%4
447
16th to endDay
14%8%26%29%12%7%
326
August1st to 15thDay
15%423%30%12%13%
313
16th to endDay
20%421%21%19%11%
332
September1st to 15thDay
13%6%25%26%16%11%
315
16th to endDay
18%5%22%25%18%9%
287
October1st to 15thDay
26%9%29%20%12%2
255
16th to endDay
37%13%27%16%4
272
November1st to 15thDay
27%13%27%22%8%
68
16th to endDay
31%23%30%15%
60
December1st to 15thDay
31%26%23%11%6%
60
16th to endDay
40%35%20%11
64
January1st to 15thNight
33%17%28%15%4
781
16th to endNight
24%12%31%22%7%1
768
February1st to 15thNight
23%17%32%21%5%
704
16th to endNight
26%14%30%20%6%
631
March1st to 15thNight
25%16%30%23%3
720
16th to endNight
21%11%29%26%10%
768
April1st to 15thNight
29%13%27%23%5%
718
16th to endNight
23%10%28%24%12%
540
May1st to 15thNight
22%7%21%31%14%1
465
16th to endNight
14%8%29%31%15%
375
June1st to 15thNight
15%7%25%38%11%
360
16th to endNight
16%5%24%37%15%
360
July1st to 15thNight
7%222%46%18%1
340
16th to endNight
11%425%34%23%
454
August1st to 15thNight
10%416%38%25%4
539
16th to endNight
13%321%31%27%2
609
September1st to 15thNight
17%5%25%26%18%6%
720
16th to endNight
17%5%20%32%20%3
693
October1st to 15thNight
26%9%25%25%11%1
660
16th to endNight
35%13%26%17%5%
704
November1st to 15thNight
26%13%28%20%10%1
700
16th to endNight
33%12%28%19%4
720
December1st to 15thNight
37%18%27%13%3
720
16th to endNight
34%16%29%16%2
792
Page generated at 2017-09-25 09:02:20. Version ac04

Copyright 2017 A. Danko


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