Mission Rosario State Historic Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mission Rosario State Historic Site clear sky chart from 2005-11-05 to 2017-09-22.

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
53%
15328
23%
47015
17%
15283
58%
15283
31%
28116

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
38%
897
22%
2327
11%
895
45%
895
29%
1557
January16th to endNight
39%
888
24%
2424
10%
888
48%
888
30%
1558
February1st to 15thNight
38%
704
25%
2110
13%
699
47%
699
26%
1308
February16th to endNight
30%
605
24%
1867
9%
605
42%
605
26%
1135
March1st to 15thNight
35%
540
25%
1980
14%
540
49%
540
22%
1222
March16th to endNight
38%
576
22%
2112
17%
576
47%
576
26%
1204
April1st to 15thNight
32%
539
19%
1977
11%
539
44%
539
24%
1182
April16th to endNight
34%
540
21%
1843
16%
540
43%
540
21%
1180
May1st to 15thNight
37%
539
20%
1620
13%
539
46%
539
27%
1042
May16th to endNight
53%
563
22%
1684
20%
561
60%
561
30%
1042
June1st to 15thNight
72%
540
18%
1620
21%
540
74%
540
41%
891
June16th to endNight
72%
540
16%
1620
18%
540
73%
540
31%
998
July1st to 15thNight
76%
510
18%
1530
21%
510
77%
510
37%
881
July16th to endNight
85%
564
20%
1594
23%
531
86%
531
42%
872
August1st to 15thNight
91%
539
27%
1653
30%
536
91%
536
56%
778
August16th to endNight
78%
573
17%
2021
22%
573
79%
573
31%
1163
September1st to 15thNight
78%
540
17%
1980
22%
540
79%
540
31%
1111
September16th to endNight
72%
513
24%
1891
28%
513
74%
513
29%
1064
October1st to 15thNight
74%
520
33%
1840
33%
520
76%
520
40%
910
October16th to endNight
63%
704
35%
2112
26%
704
66%
704
46%
1084
November1st to 15thNight
55%
700
26%
2100
19%
700
57%
700
33%
1260
November16th to endNight
51%
834
30%
2274
17%
834
58%
834
39%
1321
December1st to 15thNight
40%
900
24%
2340
13%
900
44%
900
25%
1609
December16th to endNight
36%
960
19%
2496
10%
960
41%
960
25%
1744

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
11%6%35%5%35%5%5%8%39%
47855
Night
11%5%2442445%8%48%
47213
TransparencyDay
41%7%11%18%14%7%
47555
Night
34%5%13%20%15%9%
47018
SeeingDay
11%318%32%24%8%
5279
Night
14%421%35%21%2
15332

By Month

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%6%35%5%33446%38%
1611
16th to endDay
15%6%34333445%44%
1809
February1st to 15thDay
18%6%23333335%45%
1750
16th to endDay
17%7%25%323345%44%
1605
March1st to 15thDay
21%7%25%42335%6%37%
1980
16th to endDay
12%6%35%33445%7%42%
2110
April1st to 15thDay
11%7%25%6%2445%7%41%
1971
16th to endDay
14%7%35%5%24446%40%
2112
May1st to 15thDay
10%6%36%5%36%5%5%8%37%
2331
16th to endDay
8%5%36%5%37%6%6%10%35%
2430
June1st to 15thDay
4325%7%5%7%7%7%9%40%
2340
16th to endDay
7%5%38%7%49%7%7%10%29%
2340
July1st to 15thDay
9%5%26%7%5%6%6%6%10%32%
2340
16th to endDay
5%436%6%37%7%7%10%34%
2466
August1st to 15thDay
12237%36%7%7%12%45%
2293
16th to endDay
7%5%37%7%46%7%8%10%30%
2178
September1st to 15thDay
8%7%38%7%46%5%6%8%33%
1980
16th to endDay
9%5%25%6%46%6%7%7%37%
1881
October1st to 15thDay
7%4145%35%5%6%8%46%
1779
16th to endDay
7%413424445%56%
1760
November1st to 15thDay
9%6%26%5%36%5%5%7%39%
1758
16th to endDay
14%6%23423435%49%
1683
December1st to 15thDay
22%9%35%324346%34%
1620
16th to endDay
17%8%36%434446%36%
1728
January1st to 15thNight
20%5%24313346%44%
2327
16th to endNight
17%424323346%46%
2424
February1st to 15thNight
16%5%24324245%46%
2102
16th to endNight
14%6%25%323345%48%
1867
March1st to 15thNight
18%7%24324246%42%
1980
16th to endNight
13%7%24323346%49%
2112
April1st to 15thNight
12%6%25%4245%5%8%42%
1977
16th to endNight
15%7%35%5%24347%38%
1843
May1st to 15thNight
9%6%35%425%5%6%11%39%
1619
16th to endNight
7%425%5%35%6%7%11%41%
1683
June1st to 15thNight
43134345%6%9%53%
1620
16th to endNight
6%3135%35%5%8%12%42%
1620
July1st to 15thNight
42245%245%6%11%49%
1620
16th to endNight
22134245%6%13%53%
1702
August1st to 15thNight
11121337%11%64%
1663
16th to endNight
44244245%6%12%47%
2021
September1st to 15thNight
6%3244235%6%10%49%
1980
16th to endNight
8%5%25%43445%8%48%
1891
October1st to 15thNight
5%323323347%60%
1840
16th to endNight
7%312312135%65%
2112
November1st to 15thNight
10%6%14424446%49%
2100
16th to endNight
11%423313445%55%
2274
December1st to 15thNight
20%6%24423336%40%
2340
16th to endNight
18%8%35%423346%39%
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
49%35%12%15%13%
1612
16th to endDay
41%36%15%19%12%
1809
February1st to 15thDay
41%37%13%18%15%
1751
16th to endDay
42%36%16%18%11%
1605
March1st to 15thDay
47%48%12%18%9%
1980
16th to endDay
39%6%9%15%17%11%
2112
April1st to 15thDay
40%6%8%14%18%11%
1971
16th to endDay
44%5%7%17%14%10%
2112
May1st to 15thDay
42%6%12%17%13%8%
2331
16th to endDay
41%8%12%17%16%3
2434
June1st to 15thDay
34%8%12%21%18%3
2340
16th to endDay
46%8%12%22%10%
2340
July1st to 15thDay
42%9%15%21%10%
2201
16th to endDay
36%10%20%28%4
2311
August1st to 15thDay
28%9%20%32%8%
2279
16th to endDay
43%12%17%20%5%1
2178
September1st to 15thDay
46%9%12%16%12%2
1980
16th to endDay
40%8%12%16%15%6%
1881
October1st to 15thDay
32%7%10%20%17%11%
1779
16th to endDay
29%6%5%16%25%17%
1760
November1st to 15thDay
42%7%9%13%16%10%
1758
16th to endDay
38%46%14%16%18%
1683
December1st to 15thDay
52%36%13%15%8%
1620
16th to endDay
48%48%14%15%8%
1728
January1st to 15thNight
42%37%14%17%14%
2327
16th to endNight
39%37%16%18%13%
2424
February1st to 15thNight
39%39%11%18%17%
2112
16th to endNight
38%47%17%19%12%
1867
March1st to 15thNight
42%48%14%17%11%
1980
16th to endNight
36%412%16%17%12%
2112
April1st to 15thNight
38%5%11%16%15%11%
1977
16th to endNight
45%410%16%13%10%
1843
May1st to 15thNight
38%7%14%17%12%10%
1620
16th to endNight
34%8%16%23%14%1
1685
June1st to 15thNight
25%6%17%26%21%2
1620
16th to endNight
31%10%18%28%10%
1620
July1st to 15thNight
27%8%24%32%6%
1530
16th to endNight
20%10%32%32%4
1594
August1st to 15thNight
13%6%28%43%6%
1653
16th to endNight
28%11%28%25%5%
2021
September1st to 15thNight
29%8%22%22%13%3
1980
16th to endNight
32%7%14%24%15%5%
1891
October1st to 15thNight
23%5%12%27%19%12%
1840
16th to endNight
23%36%19%28%18%
2112
November1st to 15thNight
34%5%13%19%18%9%
2100
16th to endNight
30%311%16%17%20%
2274
December1st to 15thNight
45%47%17%15%9%
2340
16th to endNight
46%47%14%16%11%
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
18%334%37%41
90
16th to endDay
16%8%41%22%10%
96
February1st to 15thDay
10%11%36%26%15%
90
16th to endDay
17%6%40%24%11%
81
March1st to 15thDay
32%8%27%22%8%
90
16th to endDay
14%11%31%30%12%
96
April1st to 15thDay
15%12%31%32%8%
90
16th to endDay
19%7%37%22%12%
222
May1st to 15thDay
14%10%42%25%7%
468
16th to endDay
11%433%32%15%1
517
June1st to 15thDay
5%13%41%32%7%
495
16th to endDay
10%110%36%30%11%
495
July1st to 15thDay
6%18%36%34%12%
475
16th to endDay
5%1335%38%16%
515
August1st to 15thDay
2336%35%21%
446
16th to endDay
12%16%37%22%18%
218
September1st to 15thDay
7%228%41%20%
135
16th to endDay
2317%49%26%
108
October1st to 15thDay
1337%44%13%
90
16th to endDay
15%210%39%27%5%
96
November1st to 15thDay
16%326%33%17%2
90
16th to endDay
27%7%24%25%7%6%
90
December1st to 15thDay
41%215%20%14%6%
90
16th to endDay
29%14%33%14%6%2
96
January1st to 15thNight
24%7%24%32%11%
900
16th to endNight
20%6%29%35%7%
888
February1st to 15thNight
20%9%28%34%7%
704
16th to endNight
18%8%39%27%6%
605
March1st to 15thNight
23%5%29%34%6%
540
16th to endNight
15%9%32%35%7%
576
April1st to 15thNight
15%6%41%30%6%
539
16th to endNight
18%7%36%29%7%
540
May1st to 15thNight
13%6%38%36%4
540
16th to endNight
9%229%41%16%
563
June1st to 15thNight
6%12%52%26%1
540
16th to endNight
8%10%43%34%2
540
July1st to 15thNight
5%7%41%41%4
510
16th to endNight
3340%46%6%
564
August1st to 15thNight
1240%49%6%
539
16th to endNight
7%430%52%6%
573
September1st to 15thNight
8%1227%52%7%
540
16th to endNight
10%7%30%43%7%
513
October1st to 15thNight
7%110%39%37%3
520
16th to endNight
8%320%40%25%2
704
November1st to 15thNight
14%322%37%20%2
700
16th to endNight
14%425%33%19%2
834
December1st to 15thNight
24%6%24%30%13%1
900
16th to endNight
22%8%25%30%11%1
960
Page generated at 2017-09-23 05:43:39. Version ac04

Copyright 2017 A. Danko


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