Rio Verde Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rio Verde Observatory clear sky chart from 2005-11-05 to 2017-10-06.

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
79%
15692
37%
47125
34%
15654
83%
15654
56%
22123

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
70%
718
32%
2327
32%
716
77%
716
46%
1129
January16th to endNight
68%
768
37%
2496
36%
768
75%
768
43%
1264
February1st to 15thNight
74%
698
36%
2196
36%
698
81%
698
53%
1018
February16th to endNight
70%
632
37%
1877
37%
632
75%
632
46%
974
March1st to 15thNight
74%
720
41%
1980
35%
720
79%
720
60%
947
March16th to endNight
79%
768
40%
2112
33%
768
84%
768
63%
989
April1st to 15thNight
76%
699
34%
1958
27%
699
81%
699
57%
961
April16th to endNight
77%
540
45%
1709
39%
540
84%
540
70%
669
May1st to 15thNight
78%
539
40%
1619
34%
539
83%
539
69%
677
May16th to endNight
82%
561
40%
1684
33%
561
85%
561
74%
671
June1st to 15thNight
87%
540
35%
1620
31%
540
87%
540
73%
651
June16th to endNight
92%
540
35%
1620
32%
540
92%
540
75%
644
July1st to 15thNight
84%
510
24%
1530
21%
510
84%
510
50%
765
July16th to endNight
82%
564
27%
1593
23%
531
82%
531
41%
869
August1st to 15thNight
83%
539
30%
1611
26%
536
83%
536
47%
834
August16th to endNight
85%
624
33%
1857
32%
624
85%
624
45%
993
September1st to 15thNight
85%
720
33%
1980
30%
720
86%
720
53%
1030
September16th to endNight
85%
716
44%
1980
36%
716
88%
716
67%
896
October1st to 15thNight
82%
684
41%
1964
35%
684
86%
684
65%
884
October16th to endNight
85%
704
44%
2112
39%
704
89%
704
67%
897
November1st to 15thNight
84%
700
43%
2124
40%
700
87%
700
66%
901
November16th to endNight
78%
720
40%
2340
40%
720
83%
720
55%
1034
December1st to 15thNight
74%
720
37%
2340
38%
720
78%
720
48%
1119
December16th to endNight
68%
768
35%
2496
36%
768
72%
768
40%
1307

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
3212213346%69%
48071
Night
4112213345%68%
47321
TransparencyDay
17%2312%25%38%
47766
Night
18%2311%24%39%
47127
SeeingDay
4418%36%27%7%
5513
Night
5%18%41%37%4
15703

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
6%212322235%66%
1611
16th to endDay
8%312322235%64%
1728
February1st to 15thDay
4313212246%67%
1665
16th to endDay
8%313212347%60%
1597
March1st to 15thDay
5%211313336%67%
1980
16th to endDay
311331233471%
2112
April1st to 15thDay
311213346%70%
1988
16th to endDay
21111212379%
2249
May1st to 15thDay
111112135%80%
2331
16th to endDay
2111122381%
2429
June1st to 15thDay
11111112482%
2340
16th to endDay
111222481%
2340
July1st to 15thDay
22124245%6%9%58%
2340
16th to endDay
5%214426%7%7%11%45%
2467
August1st to 15thDay
32133245%6%8%57%
2340
16th to endDay
21133245%7%7%59%
2342
September1st to 15thDay
321232435%5%65%
1980
16th to endDay
21111113480%
1980
October1st to 15thDay
211222235%76%
1791
16th to endDay
11121222479%
1760
November1st to 15thDay
11221234474%
1733
16th to endDay
5%1221113472%
1620
December1st to 15thDay
7%313313226%63%
1620
16th to endDay
8%413313345%59%
1728
January1st to 15thNight
6%21332333465%
2327
16th to endNight
9%21331333463%
2496
February1st to 15thNight
5%212212245%67%
2185
16th to endNight
7%213323345%61%
1877
March1st to 15thNight
5%212212245%69%
1980
16th to endNight
211212235%73%
2112
April1st to 15thNight
4112213336%68%
1958
16th to endNight
211211382%
1709
May1st to 15thNight
111212245%77%
1619
16th to endNight
21111112384%
1684
June1st to 15thNight
11111223480%
1620
16th to endNight
111223481%
1620
July1st to 15thNight
2112435%5%6%10%55%
1620
16th to endNight
3245%35%6%7%12%46%
1701
August1st to 15thNight
12145%15%5%6%9%54%
1620
16th to endNight
22145%35%5%7%7%54%
1857
September1st to 15thNight
221333445%8%61%
1980
16th to endNight
21121233477%
1980
October1st to 15thNight
222212235%75%
1964
16th to endNight
121211223378%
2112
November1st to 15thNight
211112335%74%
2124
16th to endNight
411221222472%
2340
December1st to 15thNight
8%22223435%64%
2340
16th to endNight
10%22332334459%
2496

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
21%1414%28%28%
1612
16th to endDay
23%1317%25%28%
1728
February1st to 15thDay
20%15%17%27%28%
1665
16th to endDay
24%1317%29%23%
1597
March1st to 15thDay
19%119%32%36%
1980
16th to endDay
18%1210%33%33%
2112
April1st to 15thDay
14%1110%34%36%
1988
16th to endDay
11%18%26%51%
2249
May1st to 15thDay
9%118%26%52%
2331
16th to endDay
10%17%24%56%
2432
June1st to 15thDay
9%418%67%
2340
16th to endDay
8%11412%71%
2340
July1st to 15thDay
19%49%16%17%31%
2201
16th to endDay
28%5%14%24%17%9%
2312
August1st to 15thDay
21%48%19%19%26%
2325
16th to endDay
21%36%20%25%22%
2342
September1st to 15thDay
20%35%15%25%30%
1980
16th to endDay
10%16%30%50%
1980
October1st to 15thDay
13%139%27%44%
1791
16th to endDay
11%148%27%47%
1760
November1st to 15thDay
13%1111%33%38%
1733
16th to endDay
17%1212%25%41%
1620
December1st to 15thDay
25%1417%27%23%
1620
16th to endDay
27%1421%28%15%
1728
January1st to 15thNight
23%2411%26%31%
2327
16th to endNight
26%2213%27%28%
2496
February1st to 15thNight
19%1416%26%31%
2196
16th to endNight
24%2214%28%27%
1877
March1st to 15thNight
17%119%28%42%
1980
16th to endNight
14%1211%32%37%
2112
April1st to 15thNight
18%118%29%39%
1958
16th to endNight
9%116%24%57%
1709
May1st to 15thNight
10%127%27%50%
1620
16th to endNight
9%18%18%62%
1685
June1st to 15thNight
9%11314%70%
1620
16th to endNight
8%1139%74%
1620
July1st to 15thNight
21%312%14%15%32%
1530
16th to endNight
25%5%14%20%20%12%
1593
August1st to 15thNight
23%39%19%15%28%
1611
16th to endNight
24%48%16%22%23%
1857
September1st to 15thNight
20%36%20%21%26%
1980
16th to endNight
12%2424%54%
1980
October1st to 15thNight
13%1110%24%47%
1964
16th to endNight
12%128%20%54%
2112
November1st to 15thNight
12%1111%30%42%
2124
16th to endNight
18%1210%23%43%
2340
December1st to 15thNight
22%2414%28%28%
2340
16th to endNight
29%15%16%28%18%
2496

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
27%120%33%15%2
90
16th to endDay
10%310%42%25%8%
96
February1st to 15thDay
5%221%41%26%2
180
16th to endDay
12%8%27%34%14%2
238
March1st to 15thDay
5%11%26%31%15%10%
270
16th to endDay
410%30%30%17%6%
288
April1st to 15thDay
5%13%26%33%16%4
269
16th to endDay
415%33%31%13%2
270
May1st to 15thDay
312%28%36%15%3
288
16th to endDay
26%28%37%22%2
330
June1st to 15thDay
2225%40%24%4
315
16th to endDay
113%44%29%10%
315
July1st to 15thDay
111%40%37%8%
305
16th to endDay
41431%35%22%
327
August1st to 15thDay
25%32%46%14%
315
16th to endDay
1434%43%15%
332
September1st to 15thDay
6%110%35%38%6%
315
16th to endDay
5%317%37%32%4
315
October1st to 15thDay
3318%41%28%5%
193
16th to endDay
36%30%52%8%
96
November1st to 15thDay
3117%36%28%12%
90
16th to endDay
7%221%40%28%
90
December1st to 15thDay
4110%40%41%3
90
16th to endDay
17%121%41%16%1
96
January1st to 15thNight
7%13%52%22%2
720
16th to endNight
11%112%47%24%3
768
February1st to 15thNight
6%110%55%24%2
704
16th to endNight
9%14%50%22%1
632
March1st to 15thNight
5%113%46%28%3
720
16th to endNight
329%46%32%5%
768
April1st to 15thNight
4210%51%27%2
699
16th to endNight
2215%47%27%3
540
May1st to 15thNight
2213%45%32%4
540
16th to endNight
2210%42%38%3
563
June1st to 15thNight
117%44%41%3
540
16th to endNight
1234%55%5%
540
July1st to 15thNight
1327%61%5%
510
16th to endNight
41213%64%14%
564
August1st to 15thNight
3116%65%12%
539
16th to endNight
2219%66%8%
624
September1st to 15thNight
4329%53%8%
720
16th to endNight
36%38%44%6%
716
October1st to 15thNight
39%45%38%2
684
16th to endNight
16%43%40%6%
704
November1st to 15thNight
38%49%34%4
700
16th to endNight
5%10%46%32%4
720
December1st to 15thNight
10%19%47%29%1
720
16th to endNight
11%19%50%23%2
768
Page generated at 2017-10-07 11:07:45. Version ac04

Copyright 2017 A. Danko


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