Rattle Snake Springs
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rattle Snake Springs clear sky chart from 2005-11-05 to 2017-09-23.

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
51%
15525
34%
46943
20%
15485
65%
15485
41%
23156

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
40%
717
32%
2327
19%
716
56%
716
34%
1165
January16th to endNight
40%
768
39%
2376
18%
768
62%
768
41%
1131
February1st to 15thNight
43%
702
36%
2112
18%
700
61%
700
43%
985
February16th to endNight
31%
632
39%
1894
13%
632
56%
632
41%
889
March1st to 15thNight
41%
720
35%
2110
17%
720
56%
720
38%
1074
March16th to endNight
40%
669
38%
2013
16%
669
61%
669
44%
952
April1st to 15thNight
32%
539
35%
1798
14%
539
58%
539
37%
825
April16th to endNight
37%
540
40%
1800
20%
540
68%
540
48%
740
May1st to 15thNight
37%
539
30%
1799
18%
539
58%
539
41%
830
May16th to endNight
47%
562
30%
1736
19%
561
64%
561
41%
855
June1st to 15thNight
64%
540
29%
1542
21%
540
72%
540
49%
736
June16th to endNight
66%
540
27%
1440
20%
540
71%
540
47%
758
July1st to 15thNight
74%
510
24%
1476
22%
510
76%
510
41%
804
July16th to endNight
70%
564
24%
1710
22%
531
79%
531
36%
912
August1st to 15thNight
79%
539
26%
1789
32%
536
80%
536
39%
899
August16th to endNight
78%
573
22%
1910
26%
573
80%
573
34%
1060
September1st to 15thNight
70%
540
24%
1800
26%
540
72%
540
31%
1024
September16th to endNight
71%
516
34%
1889
30%
516
79%
516
36%
905
October1st to 15thNight
63%
564
37%
1884
30%
564
70%
564
45%
884
October16th to endNight
68%
704
41%
2112
24%
704
78%
704
57%
931
November1st to 15thNight
55%
790
40%
2190
21%
790
66%
790
51%
1031
November16th to endNight
47%
900
39%
2340
15%
900
62%
900
44%
1205
December1st to 15thNight
40%
900
37%
2340
15%
900
55%
900
42%
1244
December16th to endNight
35%
957
37%
2556
13%
957
53%
957
41%
1317

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
421232335%7%63%
47923
Night
4212223347%64%
47151
Cloud CoverDay
4212323447%62%
47921
Night
4212223347%64%
47151
TransparencyDay
20%49%17%25%23%
47632
Night
19%48%16%25%25%
46945
SeeingDay
6%13%18%28%24%8%
5380
Night
5%19%20%31%21%2
15532

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
4423323346%62%
1611
16th to endDay
5%312322345%66%
1844
February1st to 15thDay
333223245%69%
1750
16th to endDay
241221333469%
1580
March1st to 15thDay
4212214347%64%
1846
16th to endDay
3213322246%67%
2211
April1st to 15thDay
4212213345%67%
2150
16th to endDay
11111212479%
2160
May1st to 15thDay
4212312346%67%
2151
16th to endDay
5%111212345%69%
2375
June1st to 15thDay
111221245%8%68%
2412
16th to endDay
421232446%9%58%
2520
July1st to 15thDay
6%2134245%7%11%50%
2391
16th to endDay
6%213325%45%10%52%
2337
August1st to 15thDay
41124347%9%11%50%
2160
16th to endDay
5%3135%35%7%8%11%43%
2292
September1st to 15thDay
11%413425%46%9%47%
2160
16th to endDay
7%312313446%60%
1905
October1st to 15thDay
7%312213236%66%
1743
16th to endDay
321231112475%
1760
November1st to 15thDay
422212235%71%
1654
16th to endDay
431111224471%
1620
December1st to 15thDay
441312245%6%63%
1620
16th to endDay
5%413213347%63%
1671
January1st to 15thNight
5%313324336%61%
2327
16th to endNight
5%212212345%67%
2376
February1st to 15thNight
3212112345%70%
2102
16th to endNight
5%212112336%68%
1894
March1st to 15thNight
4312323345%64%
2110
16th to endNight
3212222245%69%
2013
April1st to 15thNight
3213323335%67%
1798
16th to endNight
2112111235%76%
1800
May1st to 15thNight
4111323345%67%
1799
16th to endNight
6%1222245%6%64%
1735
June1st to 15thNight
11221347%9%63%
1542
16th to endNight
31231446%10%60%
1440
July1st to 15thNight
5%2123245%8%12%52%
1566
16th to endNight
41134346%7%11%51%
1828
August1st to 15thNight
31134345%8%14%49%
1800
16th to endNight
4213336%7%8%11%46%
1910
September1st to 15thNight
9%31343447%8%49%
1800
16th to endNight
6%21332235%8%59%
1889
October1st to 15thNight
8%1221223468%
1884
16th to endNight
31121222476%
2112
November1st to 15thNight
421212235%73%
2190
16th to endNight
431121323471%
2340
December1st to 15thNight
5%412212347%64%
2340
16th to endNight
4211313346%66%
2556

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
4324213346%62%
1611
16th to endDay
5%322212346%65%
1844
February1st to 15thDay
3212222335%69%
1750
16th to endDay
241221333469%
1580
March1st to 15thDay
4213213347%63%
1846
16th to endDay
3212322236%67%
2209
April1st to 15thDay
4212223345%67%
2150
16th to endDay
11111213479%
2160
May1st to 15thDay
4212312345%68%
2151
16th to endDay
5%11222345%68%
2375
June1st to 15thDay
111221235%8%68%
2412
16th to endDay
411232446%8%58%
2520
July1st to 15thDay
6%2234245%7%11%49%
2391
16th to endDay
6%2143245%5%10%52%
2337
August1st to 15thDay
41124347%9%10%49%
2160
16th to endDay
5%3145%36%6%8%11%43%
2292
September1st to 15thDay
11%3135%25%5%6%9%46%
2160
16th to endDay
7%312323446%59%
1905
October1st to 15thDay
7%212212235%66%
1743
16th to endDay
3212311225%75%
1760
November1st to 15thDay
422212235%71%
1654
16th to endDay
431121224471%
1620
December1st to 15thDay
432311335%6%63%
1620
16th to endDay
5%412212437%63%
1671
January1st to 15thNight
5%413323336%61%
2327
16th to endNight
5%222212345%67%
2376
February1st to 15thNight
3211213246%70%
2102
16th to endNight
5%212112236%69%
1894
March1st to 15thNight
4312324346%64%
2110
16th to endNight
3212213245%69%
2013
April1st to 15thNight
3213323335%67%
1798
16th to endNight
2112212235%76%
1800
May1st to 15thNight
4112223336%68%
1799
16th to endNight
6%1222235%7%64%
1735
June1st to 15thNight
11221347%9%63%
1542
16th to endNight
3132145%6%11%59%
1440
July1st to 15thNight
5%21232448%12%52%
1566
16th to endNight
41144345%7%11%50%
1828
August1st to 15thNight
3113435%5%7%14%49%
1800
16th to endNight
3223436%6%9%11%46%
1910
September1st to 15thNight
9%31342447%8%49%
1800
16th to endNight
6%31332245%8%59%
1889
October1st to 15thNight
7%212222235%68%
1884
16th to endNight
31221222476%
2112
November1st to 15thNight
411212335%73%
2190
16th to endNight
431122224371%
2340
December1st to 15thNight
5%412212347%64%
2340
16th to endNight
4211213346%66%
2556

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
23%35%16%28%21%
1612
16th to endDay
20%26%13%30%25%
1844
February1st to 15thDay
17%36%15%24%32%
1751
16th to endDay
19%3412%27%33%
1580
March1st to 15thDay
19%35%12%30%27%
1846
16th to endDay
19%25%12%26%33%
2211
April1st to 15thDay
18%35%9%29%34%
2150
16th to endDay
10%249%27%44%
2160
May1st to 15thDay
18%35%11%23%37%
2151
16th to endDay
17%37%14%21%34%
2378
June1st to 15thDay
13%48%17%20%35%
2412
16th to endDay
21%5%9%19%21%22%
2520
July1st to 15thDay
25%8%14%21%21%8%
2252
16th to endDay
24%6%17%28%19%3
2193
August1st to 15thDay
22%9%19%27%17%3
2147
16th to endDay
29%9%19%22%14%4
2292
September1st to 15thDay
31%7%13%19%18%8%
2160
16th to endDay
24%5%8%16%29%15%
1905
October1st to 15thDay
20%39%16%26%22%
1743
16th to endDay
14%1415%31%31%
1760
November1st to 15thDay
16%35%17%31%26%
1654
16th to endDay
17%26%12%30%31%
1620
December1st to 15thDay
20%39%20%31%14%
1620
16th to endDay
21%310%21%30%13%
1671
January1st to 15thNight
24%35%14%28%22%
2327
16th to endNight
19%35%12%33%25%
2376
February1st to 15thNight
16%37%13%22%36%
2112
16th to endNight
17%3411%27%36%
1894
March1st to 15thNight
20%45%13%26%29%
2110
16th to endNight
18%2413%24%36%
2013
April1st to 15thNight
19%35%10%26%33%
1798
16th to endNight
12%2410%24%44%
1800
May1st to 15thNight
18%46%11%22%37%
1800
16th to endNight
18%6%8%14%20%32%
1737
June1st to 15thNight
15%411%16%21%31%
1542
16th to endNight
17%6%16%19%20%20%
1440
July1st to 15thNight
21%8%15%25%21%7%
1476
16th to endNight
22%9%18%24%22%3
1710
August1st to 15thNight
22%6%16%26%22%5%
1789
16th to endNight
26%9%16%26%14%6%
1910
September1st to 15thNight
29%8%13%19%17%10%
1800
16th to endNight
23%5%9%20%26%14%
1889
October1st to 15thNight
20%37%17%24%26%
1884
16th to endNight
13%25%15%27%36%
2112
November1st to 15thNight
14%2416%32%29%
2190
16th to endNight
17%3411%28%34%
2340
December1st to 15thNight
20%26%19%27%23%
2340
16th to endNight
18%47%18%34%17%
2556

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
15%7%35%30%11%
90
16th to endDay
5%22%33%21%15%1
96
February1st to 15thDay
410%21%34%26%3
90
16th to endDay
6%17%28%30%13%3
81
March1st to 15thDay
5%11%34%30%13%3
136
16th to endDay
428%30%25%8%1
288
April1st to 15thDay
8%27%33%24%5%1
269
16th to endDay
231%36%21%6%1
270
May1st to 15thDay
425%37%23%7%
288
16th to endDay
7%15%32%31%11%
462
June1st to 15thDay
112%15%35%31%3
495
16th to endDay
412%9%30%33%9%
495
July1st to 15thDay
48%430%37%13%
356
16th to endDay
39%224%35%24%
327
August1st to 15thDay
35%222%42%24%
315
16th to endDay
7%5%428%35%18%
332
September1st to 15thDay
7%5%7%28%37%13%
315
16th to endDay
6%8%26%45%12%
123
October1st to 15thDay
26%18%21%28%13%
90
16th to endDay
5%313%28%37%12%
96
November1st to 15thDay
16%11%12%24%25%10%
90
16th to endDay
14%14%30%25%12%3
90
December1st to 15thDay
8%12%22%41%12%3
90
16th to endDay
8%15%38%30%7%
96
January1st to 15thNight
7%21%27%29%13%2
720
16th to endNight
424%29%29%11%1
768
February1st to 15thNight
6%22%24%31%13%1
704
16th to endNight
6%25%34%26%6%
632
March1st to 15thNight
5%24%25%32%10%
720
16th to endNight
325%28%31%10%
669
April1st to 15thNight
426%34%29%5%
539
16th to endNight
126%32%30%7%
540
May1st to 15thNight
422%35%31%6%
540
16th to endNight
5%20%23%38%11%
563
June1st to 15thNight
17%12%47%21%
540
16th to endNight
317%9%42%26%1
540
July1st to 15thNight
5%11%334%42%2
510
16th to endNight
316%225%45%6%
564
August1st to 15thNight
39%219%59%6%
539
16th to endNight
48%122%55%7%
573
September1st to 15thNight
7%8%427%45%6%
540
16th to endNight
8%9%336%38%3
516
October1st to 15thNight
8%10%14%36%26%2
564
16th to endNight
412%12%35%27%7%
704
November1st to 15thNight
5%17%18%32%22%3
790
16th to endNight
6%22%20%29%18%2
900
December1st to 15thNight
8%22%26%27%13%1
900
16th to endNight
6%24%31%27%9%1
957
Page generated at 2017-09-24 07:15:50. Version ac04

Copyright 2017 A. Danko


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