Desert Hot Springs
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Desert Hot Springs 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
76%
16155
41%
47023
33%
16116
83%
16116
71%
19578

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
73%
717
36%
2327
34%
716
80%
716
57%
1005
January16th to endNight
69%
768
41%
2349
33%
768
80%
768
55%
1068
February1st to 15thNight
72%
697
39%
2107
34%
697
83%
697
61%
931
February16th to endNight
66%
632
39%
1895
38%
632
75%
632
59%
852
March1st to 15thNight
69%
720
38%
2144
34%
720
79%
720
67%
899
March16th to endNight
68%
768
40%
2066
27%
768
78%
768
71%
916
April1st to 15thNight
59%
719
39%
1799
18%
719
71%
719
71%
838
April16th to endNight
62%
720
44%
1800
19%
720
74%
720
80%
798
May1st to 15thNight
69%
539
43%
1619
28%
539
77%
539
83%
591
May16th to endNight
66%
562
41%
1685
29%
561
73%
561
82%
617
June1st to 15thNight
72%
540
36%
1620
29%
540
76%
540
84%
592
June16th to endNight
84%
540
38%
1620
33%
540
86%
540
86%
591
July1st to 15thNight
89%
510
34%
1530
29%
510
90%
510
77%
594
July16th to endNight
89%
567
38%
1596
32%
534
89%
534
69%
664
August1st to 15thNight
92%
717
39%
1790
26%
713
92%
713
84%
786
August16th to endNight
92%
764
46%
1910
32%
764
93%
764
80%
860
September1st to 15thNight
90%
720
41%
1887
32%
720
93%
720
79%
817
September16th to endNight
88%
683
50%
1890
44%
683
93%
683
88%
734
October1st to 15thNight
76%
660
46%
1815
35%
660
87%
660
79%
755
October16th to endNight
82%
704
46%
2123
43%
704
89%
704
77%
820
November1st to 15thNight
81%
700
41%
2275
39%
700
90%
700
76%
829
November16th to endNight
80%
720
44%
2340
45%
720
87%
720
69%
910
December1st to 15thNight
74%
720
38%
2340
34%
720
83%
720
57%
1003
December16th to endNight
65%
768
38%
2496
33%
768
75%
768
53%
1108

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
111112335%77%
47849
Night
111112235%78%
47224
TransparencyDay
10%1414%26%43%
47545
Night
9%15%15%28%39%
47029
SeeingDay
29%24%33%21%7%
5856
Night
1216%35%34%9%
16167

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
211313346%70%
1611
16th to endDay
32221235%7%67%
1872
February1st to 15thDay
2111113247%71%
1751
16th to endDay
111222445%8%66%
1579
March1st to 15thDay
11111135%7%75%
1815
16th to endDay
1123347%74%
2156
April1st to 15thDay
111212346%73%
2149
16th to endDay
111235%83%
2160
May1st to 15thDay
1112485%
2328
16th to endDay
122385%
2429
June1st to 15thDay
11112386%
2340
16th to endDay
11111288%
2340
July1st to 15thDay
211212345%73%
2340
16th to endDay
11232345%6%67%
2461
August1st to 15thDay
111333478%
2160
16th to endDay
1111223479%
2292
September1st to 15thDay
111113335%77%
2073
16th to endDay
1111386%
1882
October1st to 15thDay
1112235%80%
1815
16th to endDay
1111235%81%
1744
November1st to 15thDay
111112235%79%
1584
16th to endDay
11113346%74%
1620
December1st to 15thDay
22222345%9%66%
1620
16th to endDay
31222335%7%66%
1728
January1st to 15thNight
111231335%6%70%
2327
16th to endNight
312214345%69%
2349
February1st to 15thNight
21212335%73%
2101
16th to endNight
21222346%7%67%
1895
March1st to 15thNight
1111235%7%73%
2144
16th to endNight
12348%75%
2066
April1st to 15thNight
11211236%77%
1799
16th to endNight
11212385%
1800
May1st to 15thNight
112488%
1619
16th to endNight
112487%
1684
June1st to 15thNight
1111388%
1620
16th to endNight
111191%
1620
July1st to 15thNight
112135%79%
1620
16th to endNight
2213336%75%
1704
August1st to 15thNight
1123484%
1800
16th to endNight
11121484%
1910
September1st to 15thNight
11122483%
1887
16th to endNight
11192%
1890
October1st to 15thNight
11123482%
1815
16th to endNight
111122383%
2123
November1st to 15thNight
11223482%
2275
16th to endNight
111211235%77%
2340
December1st to 15thNight
21121335%8%68%
2340
16th to endNight
3112212347%67%
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
15%16%17%30%27%
1612
16th to endDay
16%27%18%28%27%
1872
February1st to 15thDay
14%16%16%30%31%
1751
16th to endDay
17%17%21%30%21%
1579
March1st to 15thDay
9%1320%31%33%
1815
16th to endDay
10%1422%32%29%
2156
April1st to 15thDay
11%1317%35%30%
2149
16th to endDay
6%218%31%41%
2160
May1st to 15thDay
6%212%32%45%
2328
16th to endDay
5%212%31%46%
2432
June1st to 15thDay
5%19%20%62%
2340
16th to endDay
6%139%78%
2340
July1st to 15thDay
12%229%18%55%
2201
16th to endDay
15%26%13%25%37%
2306
August1st to 15thDay
8%119%22%55%
2146
16th to endDay
10%139%22%53%
2292
September1st to 15thDay
11%229%21%52%
2073
16th to endDay
6%5%25%61%
1882
October1st to 15thDay
7%311%29%47%
1815
16th to endDay
7%1411%24%51%
1744
November1st to 15thDay
9%414%31%40%
1584
16th to endDay
10%5%15%28%39%
1620
December1st to 15thDay
16%17%24%22%27%
1620
16th to endDay
17%29%22%27%19%
1728
January1st to 15thNight
15%25%18%28%29%
2327
16th to endNight
17%26%19%23%30%
2349
February1st to 15thNight
14%16%18%25%33%
2112
16th to endNight
15%18%24%28%22%
1895
March1st to 15thNight
10%16%20%31%29%
2144
16th to endNight
9%18%21%32%26%
2066
April1st to 15thNight
10%8%21%35%23%
1799
16th to endNight
6%318%36%33%
1800
May1st to 15thNight
31317%36%37%
1620
16th to endNight
4417%43%30%
1685
June1st to 15thNight
4213%22%55%
1620
16th to endNight
45%13%75%
1620
July1st to 15thNight
8%19%20%59%
1530
16th to endNight
11%16%16%28%35%
1596
August1st to 15thNight
5%210%26%52%
1790
16th to endNight
7%1110%25%53%
1910
September1st to 15thNight
7%1310%23%54%
1887
16th to endNight
37%27%60%
1890
October1st to 15thNight
7%411%36%39%
1815
16th to endNight
7%410%24%51%
2123
November1st to 15thNight
7%413%33%39%
2275
16th to endNight
10%1317%29%37%
2340
December1st to 15thNight
15%29%19%25%28%
2340
16th to endNight
17%211%20%26%21%
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
12%5%16%46%17%1
90
16th to endDay
6%12%30%30%17%2
240
February1st to 15thDay
312%25%36%17%4
266
16th to endDay
6%18%30%28%13%2
238
March1st to 15thDay
417%25%30%17%4
270
16th to endDay
316%32%28%14%4
288
April1st to 15thDay
6%22%28%23%14%4
269
16th to endDay
222%34%25%12%2
270
May1st to 15thDay
215%29%32%12%6%
288
16th to endDay
13%32%32%14%6%
330
June1st to 15thDay
28%29%30%23%5%
315
16th to endDay
2426%30%25%11%
315
July1st to 15thDay
117%38%28%13%
305
16th to endDay
19%41%29%18%
327
August1st to 15thDay
1116%38%29%13%
315
16th to endDay
212%38%29%16%
332
September1st to 15thDay
2120%43%25%6%
315
16th to endDay
16%18%38%26%8%
280
October1st to 15thDay
112%27%36%21%1
255
16th to endDay
35%20%30%32%7%
182
November1st to 15thDay
7%20%21%32%18%
90
16th to endDay
28%20%35%31%2
90
December1st to 15thDay
48%14%31%31%10%
90
16th to endDay
5%5%26%40%21%1
96
January1st to 15thNight
2216%41%25%11%
720
16th to endNight
4119%37%29%6%
768
February1st to 15thNight
1218%42%28%6%
704
16th to endNight
25%23%41%21%5%
632
March1st to 15thNight
2323%37%27%6%
720
16th to endNight
1424%35%27%6%
768
April1st to 15thNight
16%29%34%22%5%
719
16th to endNight
430%31%25%6%
720
May1st to 15thNight
425%39%26%4
540
16th to endNight
428%34%28%4
563
June1st to 15thNight
223%41%28%3
540
16th to endNight
13%44%38%2
540
July1st to 15thNight
15%37%48%7%
510
16th to endNight
1435%52%6%
567
August1st to 15thNight
1330%49%15%
717
16th to endNight
2119%55%20%
764
September1st to 15thNight
5%26%51%15%
720
16th to endNight
18%32%41%15%
683
October1st to 15thNight
119%35%36%7%
660
16th to endNight
112%29%39%15%
704
November1st to 15thNight
1115%35%36%10%
700
16th to endNight
2113%36%33%13%
720
December1st to 15thNight
3115%39%30%8%
720
16th to endNight
6%419%36%25%7%
768
Page generated at 2017-09-23 03:43:38. Version ac04

Copyright 2017 A. Danko


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