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 2017-12-20.

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
78%
16046
32%
48049
30%
16009
80%
16009
51%
23578

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%
717
39%
1790
25%
713
95%
713
84%
783
August16th to endNight
96%
764
46%
1910
31%
764
96%
764
86%
831
September1st to 15thNight
94%
720
44%
1800
35%
720
94%
720
78%
824
September16th to endNight
93%
716
48%
1952
46%
716
94%
716
80%
815
October1st to 15thNight
80%
720
33%
2100
34%
720
82%
720
56%
999
October16th to endNight
82%
768
41%
2304
44%
768
86%
768
60%
1046
November1st to 15thNight
76%
760
31%
2436
35%
760
77%
760
45%
1210
November16th to endNight
73%
780
30%
2535
33%
780
75%
780
42%
1294
December1st to 15thNight
71%
780
28%
2597
31%
780
73%
780
36%
1385
December16th to endNight
60%
787
24%
2754
26%
787
64%
787
28%
1600

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%
48790
Night
3312323346%66%
48234
TransparencyDay
18%48%18%29%21%
48474
Night
18%49%20%27%19%
48050
SeeingDay
5%6%18%33%28%8%
6301
Night
429%31%40%11%
16057

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%
2160
16th to endDay
1112287%
2292
September1st to 15thDay
1111112385%
2160
16th to endDay
11122383%
2007
October1st to 15thDay
2213213345%69%
1857
16th to endDay
1212323346%67%
1920
November1st to 15thDay
4313323345%62%
1752
16th to endDay
43245%3445%7%55%
1755
December1st to 15thDay
6%5%2442445%9%50%
1690
16th to endDay
8%7%35%424446%47%
1568
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%
1800
16th to endNight
1111388%
1910
September1st to 15thNight
1222284%
1800
16th to endNight
111112485%
1952
October1st to 15thNight
2212322235%70%
2100
16th to endNight
222212246%71%
2304
November1st to 15thNight
3313324347%61%
2436
16th to endNight
431342445%8%56%
2535
December1st to 15thNight
4325%43446%8%52%
2597
16th to endNight
7%8%25%42445%7%46%
2754

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%
2146
16th to endDay
5%1210%46%33%
2292
September1st to 15thDay
7%15%14%35%37%
2160
16th to endDay
7%1317%45%25%
2007
October1st to 15thDay
16%45%21%28%23%
1857
16th to endDay
16%47%18%29%24%
1920
November1st to 15thDay
22%49%21%28%13%
1752
16th to endDay
27%5%8%18%24%15%
1755
December1st to 15thDay
28%6%11%15%19%18%
1690
16th to endDay
35%6%10%18%19%8%
1568
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%
1790
16th to endNight
41210%46%35%
1910
September1st to 15thNight
7%1314%33%38%
1800
16th to endNight
6%1319%44%25%
1952
October1st to 15thNight
16%47%19%28%23%
2100
16th to endNight
14%37%20%31%22%
2304
November1st to 15thNight
22%410%22%27%12%
2436
16th to endNight
23%5%10%20%25%13%
2535
December1st to 15thNight
27%6%10%19%20%15%
2597
16th to endNight
35%5%12%19%18%7%
2754

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%38%15%
315
16th to endDay
328%47%20%
332
September1st to 15thDay
111%34%43%8%
315
16th to endDay
112%40%40%4
315
October1st to 15thDay
15%20%41%26%3
315
16th to endDay
45%16%35%30%7%
336
November1st to 15thDay
5%413%30%32%13%
168
16th to endDay
6%9%14%31%33%4
135
December1st to 15thDay
7%320%32%31%5%
120
16th to endDay
15%13%22%26%18%4
72
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
116%64%16%
717
16th to endNight
10%64%24%
764
September1st to 15thNight
1118%59%18%
720
16th to endNight
1326%53%16%
716
October1st to 15thNight
219%33%40%11%
720
16th to endNight
38%30%43%13%
768
November1st to 15thNight
419%35%34%13%
760
16th to endNight
5%210%33%33%13%
780
December1st to 15thNight
6%310%39%31%9%
780
16th to endNight
9%6%15%37%23%8%
787
Page generated at 2017-12-21 04:04:44. Version ac04

Copyright 2017 A. Danko


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