Carrizo Plain National Monument
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carrizo Plain National Monument clear sky chart from 2005-11-05 to 2017-08-12.

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
77%
15523
32%
46516
30%
15486
79%
15486
51%
22916

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
67%
716
22%
2419
24%
716
69%
716
31%
1383
January16th to endNight
67%
768
27%
2496
31%
768
68%
768
33%
1429
February1st to 15thNight
67%
700
29%
2131
30%
700
70%
700
37%
1201
February16th to endNight
62%
632
26%
1895
27%
632
66%
632
34%
1108
March1st to 15thNight
69%
720
21%
2110
22%
720
71%
720
36%
1219
March16th to endNight
71%
768
26%
2017
22%
768
74%
768
47%
1121
April1st to 15thNight
66%
719
28%
1799
17%
719
69%
719
46%
1045
April16th to endNight
72%
720
30%
1800
15%
720
77%
720
63%
900
May1st to 15thNight
80%
683
31%
1763
20%
683
82%
683
70%
822
May16th to endNight
75%
491
34%
1615
28%
491
79%
491
63%
649
June1st to 15thNight
86%
360
36%
1440
42%
360
90%
360
69%
469
June16th to endNight
96%
360
43%
1440
52%
360
97%
360
85%
407
July1st to 15thNight
97%
340
37%
1360
46%
340
97%
340
80%
401
July16th to endNight
94%
557
40%
1586
35%
524
94%
524
73%
637
August1st to 15thNight
95%
701
39%
1750
26%
697
95%
697
84%
767
August16th to endNight
96%
700
44%
1750
29%
700
96%
700
85%
766
September1st to 15thNight
95%
660
46%
1650
36%
660
95%
660
80%
748
September16th to endNight
93%
656
46%
1789
44%
656
94%
656
80%
750
October1st to 15thNight
79%
660
33%
1925
34%
660
81%
660
53%
937
October16th to endNight
81%
704
40%
2112
42%
704
85%
704
58%
967
November1st to 15thNight
77%
700
32%
2244
36%
700
78%
700
47%
1091
November16th to endNight
72%
720
29%
2340
31%
720
75%
720
41%
1204
December1st to 15thNight
69%
720
28%
2397
30%
720
71%
720
34%
1317
December16th to endNight
59%
768
23%
2688
25%
768
63%
768
27%
1578

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
3312313336%67%
47455
Night
3312323346%66%
46701
TransparencyDay
18%48%18%29%21%
47139
Night
19%49%20%27%18%
46517
SeeingDay
5%7%19%33%27%7%
5837
Night
429%30%39%11%
15534

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
5%5%23435%5%6%7%51%
1516
16th to endDay
6%7%245%2435%7%49%
1728
February1st to 15thDay
7%7%35%42335%7%50%
1730
16th to endDay
6%5%36%434348%47%
1579
March1st to 15thDay
45%245%35%6%5%10%47%
1848
16th to endDay
3424435%5%6%8%52%
2205
April1st to 15thDay
5%5%24424347%54%
2149
16th to endDay
3211314448%64%
2160
May1st to 15thDay
221213336%71%
2187
16th to endDay
311222236%71%
2496
June1st to 15thDay
111112336%76%
2520
16th to endDay
111388%
2520
July1st to 15thDay
1111135%82%
2520
16th to endDay
111111223478%
2471
August1st to 15thDay
1111386%
2114
16th to endDay
1112286%
2100
September1st to 15thDay
11111111386%
1980
16th to endDay
12122383%
1840
October1st to 15thDay
2214213346%66%
1702
16th to endDay
1212323346%67%
1760
November1st to 15thDay
4313323345%64%
1614
16th to endDay
44245%3445%6%55%
1620
December1st to 15thDay
6%5%25%4245%5%9%48%
1560
16th to endDay
8%7%35%424446%47%
1536
January1st to 15thNight
5%6%25%5%4445%8%47%
2419
16th to endNight
6%425%5%25%5%6%7%48%
2496
February1st to 15thNight
5%5%2442445%8%51%
2120
16th to endNight
6%3245%345%6%6%51%
1895
March1st to 15thNight
3423435%5%7%8%50%
2110
16th to endNight
23124235%6%10%56%
2017
April1st to 15thNight
431322435%7%61%
1799
16th to endNight
2111122337%71%
1800
May1st to 15thNight
11111147%76%
1763
16th to endNight
12111245%78%
1614
June1st to 15thNight
111222483%
1440
16th to endNight
2291%
1440
July1st to 15thNight
123486%
1440
16th to endNight
1111112482%
1693
August1st to 15thNight
11289%
1760
16th to endNight
1111388%
1750
September1st to 15thNight
1222285%
1650
16th to endNight
111122484%
1789
October1st to 15thNight
2213323345%68%
1925
16th to endNight
222312246%70%
2112
November1st to 15thNight
3312323347%63%
2244
16th to endNight
431342445%8%56%
2340
December1st to 15thNight
5%425%43446%8%50%
2397
16th to endNight
7%8%25%4245%5%7%46%
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
27%6%10%21%19%13%
1516
16th to endDay
33%7%10%14%17%17%
1728
February1st to 15thDay
32%48%20%21%12%
1730
16th to endDay
33%5%11%24%20%4
1579
March1st to 15thDay
29%7%14%21%17%9%
1848
16th to endDay
27%6%15%23%22%4
2205
April1st to 15thDay
29%5%11%25%22%6%
2149
16th to endDay
17%5%14%24%28%8%
2160
May1st to 15thDay
14%49%25%33%13%
2187
16th to endDay
15%39%29%34%8%
2499
June1st to 15thDay
9%48%19%33%24%
2520
16th to endDay
4137%36%46%
2520
July1st to 15thDay
6%1410%27%49%
2371
16th to endDay
10%36%12%34%32%
2315
August1st to 15thDay
6%312%34%42%
2100
16th to endDay
5%1210%46%32%
2100
September1st to 15thDay
6%1412%33%40%
1980
16th to endDay
7%1317%43%26%
1840
October1st to 15thDay
18%46%23%28%19%
1702
16th to endDay
16%47%18%30%22%
1760
November1st to 15thDay
21%410%19%30%14%
1614
16th to endDay
27%5%8%17%24%16%
1620
December1st to 15thDay
30%7%12%16%19%13%
1560
16th to endDay
36%6%10%18%18%8%
1536
January1st to 15thNight
32%6%9%19%19%12%
2419
16th to endNight
31%6%11%14%18%17%
2496
February1st to 15thNight
29%5%9%20%23%10%
2131
16th to endNight
30%6%11%25%22%3
1895
March1st to 15thNight
27%8%13%24%18%7%
2110
16th to endNight
20%7%18%26%22%4
2017
April1st to 15thNight
23%6%12%30%21%5%
1799
16th to endNight
12%417%29%26%8%
1800
May1st to 15thNight
9%411%29%34%11%
1764
16th to endNight
10%310%29%36%9%
1615
June1st to 15thNight
6%39%21%33%25%
1440
16th to endNight
3128%39%45%
1440
July1st to 15thNight
415%11%26%50%
1360
16th to endNight
7%3415%29%38%
1586
August1st to 15thNight
5%1211%33%46%
1750
16th to endNight
5%1210%44%36%
1750
September1st to 15thNight
7%1312%32%42%
1650
16th to endNight
6%1319%42%26%
1789
October1st to 15thNight
18%48%21%29%18%
1925
16th to endNight
15%37%21%32%19%
2112
November1st to 15thNight
20%410%22%28%13%
2244
16th to endNight
24%5%10%19%25%14%
2340
December1st to 15thNight
29%6%10%20%21%11%
2397
16th to endNight
36%5%12%19%17%7%
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
13%7%31%36%9%1
144
16th to endDay
15%9%27%32%13%2
256
February1st to 15thDay
9%10%26%32%18%3
263
16th to endDay
12%15%30%27%12%2
238
March1st to 15thDay
9%14%27%30%17%1
270
16th to endDay
5%14%28%33%15%2
288
April1st to 15thDay
10%16%31%26%13%1
269
16th to endDay
415%36%27%12%2
270
May1st to 15thDay
8%8%25%35%16%5%
288
16th to endDay
48%22%37%21%5%
330
June1st to 15thDay
15%20%37%28%6%
315
16th to endDay
10%32%40%15%
315
July1st to 15thDay
430%44%19%
305
16th to endDay
1328%45%20%
327
August1st to 15thDay
18%35%39%15%
300
16th to endDay
330%46%18%
268
September1st to 15thDay
210%31%45%9%
255
16th to endDay
112%43%37%4
255
October1st to 15thDay
15%22%40%27%2
255
16th to endDay
36%20%36%29%4
272
November1st to 15thDay
46%12%21%37%17%
120
16th to endDay
8%11%18%33%25%2
90
December1st to 15thDay
11%320%38%26%
80
16th to endDay
17%14%21%28%15%3
64
January1st to 15thNight
8%312%33%26%15%
720
16th to endNight
10%312%37%27%8%
768
February1st to 15thNight
8%311%38%27%10%
704
16th to endNight
8%8%14%36%24%7%
632
March1st to 15thNight
6%5%13%39%28%7%
720
16th to endNight
45%13%36%35%5%
768
April1st to 15thNight
6%5%15%40%26%4
719
16th to endNight
3416%34%33%7%
720
May1st to 15thNight
2210%36%39%8%
684
16th to endNight
2314%34%40%4
493
June1st to 15thNight
8%35%48%5%
360
16th to endNight
1228%60%7%
360
July1st to 15thNight
12%67%18%
340
16th to endNight
17%64%26%
557
August1st to 15thNight
115%65%16%
701
16th to endNight
10%64%24%
700
September1st to 15thNight
1116%60%19%
660
16th to endNight
325%53%16%
656
October1st to 15thNight
2110%31%41%12%
660
16th to endNight
38%31%42%13%
704
November1st to 15thNight
4210%33%35%14%
700
16th to endNight
5%211%34%32%13%
720
December1st to 15thNight
6%310%39%29%9%
720
16th to endNight
9%6%15%36%23%8%
768
Page generated at 2017-08-13 11:16:16. Version ac04

Copyright 2017 A. Danko


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