Furnace Creek
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Furnace Creek clear sky chart from 2005-11-05 to 2018-02-22.

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
72%
16193
38%
48762
30%
16153
80%
16153
59%
21409

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
71%
779
31%
2716
28%
776
80%
776
49%
1187
January16th to endNight
67%
832
36%
2642
30%
832
78%
832
46%
1286
February1st to 15thNight
68%
760
35%
2288
30%
759
77%
759
51%
1093
February16th to endNight
60%
660
37%
1979
32%
660
71%
660
49%
962
March1st to 15thNight
65%
720
34%
2160
28%
720
77%
720
55%
958
March16th to endNight
61%
768
39%
2034
25%
768
72%
768
57%
986
April1st to 15thNight
57%
719
37%
1799
16%
719
68%
719
57%
903
April16th to endNight
61%
693
39%
1773
18%
693
70%
693
64%
832
May1st to 15thNight
66%
539
37%
1619
24%
539
72%
539
64%
666
May16th to endNight
66%
561
35%
1684
25%
561
73%
561
62%
694
June1st to 15thNight
74%
444
35%
1524
33%
444
80%
444
67%
554
June16th to endNight
84%
360
40%
1440
44%
360
91%
360
76%
433
July1st to 15thNight
85%
340
34%
1360
39%
340
89%
340
61%
474
July16th to endNight
80%
514
37%
1543
34%
481
82%
481
61%
658
August1st to 15thNight
80%
664
38%
1738
24%
661
83%
661
76%
777
August16th to endNight
86%
764
44%
1910
28%
764
87%
764
79%
866
September1st to 15thNight
83%
720
40%
1863
28%
720
88%
720
71%
863
September16th to endNight
82%
716
50%
1980
40%
716
90%
716
83%
781
October1st to 15thNight
75%
720
41%
1980
32%
720
83%
720
67%
878
October16th to endNight
78%
768
45%
2388
42%
768
86%
768
65%
970
November1st to 15thNight
75%
760
38%
2470
35%
760
84%
760
63%
987
November16th to endNight
75%
780
41%
2535
40%
780
82%
780
59%
1050
December1st to 15thNight
70%
780
36%
2535
30%
780
79%
780
48%
1169
December16th to endNight
64%
832
33%
2802
29%
832
73%
832
37%
1382

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
111112236%77%
49476
Night
111212235%76%
48951
TransparencyDay
11%35%14%27%37%
49159
Night
12%35%15%26%36%
48768
SeeingDay
411%31%34%14%3
6233
Night
25%17%37%32%4
16201

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
11211235%7%71%
1552
16th to endDay
2212322347%68%
1927
February1st to 15thDay
11111335%9%69%
1901
16th to endDay
221213447%67%
1641
March1st to 15thDay
1113349%73%
1800
16th to endDay
1221235%9%69%
2185
April1st to 15thDay
1221235%6%73%
2149
16th to endDay
1111123480%
2187
May1st to 15thDay
111237%80%
2331
16th to endDay
11111236%77%
2429
June1st to 15thDay
123483%
2433
16th to endDay
1111388%
2520
July1st to 15thDay
1112112245%74%
2520
16th to endDay
111213346%72%
2515
August1st to 15thDay
11122384%
2210
16th to endDay
1122385%
2292
September1st to 15thDay
11232482%
2097
16th to endDay
111389%
1980
October1st to 15thDay
1112235%79%
1980
16th to endDay
11112235%78%
1830
November1st to 15thDay
1111111235%78%
1719
16th to endDay
1111235%6%76%
1755
December1st to 15thDay
212323347%68%
1755
16th to endDay
1223313348%64%
1768
January1st to 15thNight
112223347%70%
2716
16th to endNight
2212324346%67%
2642
February1st to 15thNight
2112213348%68%
2281
16th to endNight
3213212346%68%
1979
March1st to 15thNight
11112348%72%
2160
16th to endNight
1112112347%72%
2034
April1st to 15thNight
21111235%5%75%
1799
16th to endNight
111223479%
1773
May1st to 15thNight
112225%81%
1619
16th to endNight
112123480%
1684
June1st to 15thNight
11122483%
1524
16th to endNight
1111388%
1440
July1st to 15thNight
111112235%77%
1440
16th to endNight
11121334475%
1650
August1st to 15thNight
111112483%
1747
16th to endNight
1122483%
1910
September1st to 15thNight
111233480%
1863
16th to endNight
112388%
1980
October1st to 15thNight
1112245%77%
1980
16th to endNight
11111122481%
2388
November1st to 15thNight
121123479%
2470
16th to endNight
11111347%75%
2535
December1st to 15thNight
2212212347%69%
2535
16th to endNight
2213323448%63%
2802

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
14%5%9%33%28%8%
1552
16th to endDay
18%49%28%26%12%
1927
February1st to 15thDay
14%5%9%21%31%17%
1901
16th to endDay
16%5%9%19%32%15%
1641
March1st to 15thDay
10%48%22%34%19%
1800
16th to endDay
12%49%21%31%20%
2185
April1st to 15thDay
13%45%17%33%25%
2149
16th to endDay
10%2415%34%32%
2187
May1st to 15thDay
7%3412%30%41%
2331
16th to endDay
10%2412%34%35%
2432
June1st to 15thDay
7%227%21%58%
2433
16th to endDay
411311%77%
2520
July1st to 15thDay
11%236%15%59%
2371
16th to endDay
12%35%8%16%52%
2359
August1st to 15thDay
7%136%15%66%
2195
16th to endDay
6%225%20%62%
2292
September1st to 15thDay
8%246%18%59%
2097
16th to endDay
4117%30%53%
1980
October1st to 15thDay
10%2312%31%39%
1980
16th to endDay
9%3412%35%34%
1830
November1st to 15thDay
10%25%20%42%17%
1719
16th to endDay
10%46%24%35%18%
1755
December1st to 15thDay
17%411%22%30%12%
1755
16th to endDay
21%5%12%25%24%10%
1768
January1st to 15thNight
16%47%28%32%11%
2716
16th to endNight
20%47%22%26%17%
2642
February1st to 15thNight
17%48%19%29%20%
2292
16th to endNight
18%46%21%29%19%
1979
March1st to 15thNight
13%46%20%32%23%
2160
16th to endNight
13%36%20%34%21%
2034
April1st to 15thNight
11%5%6%15%36%25%
1799
16th to endNight
9%3313%32%37%
1773
May1st to 15thNight
8%3314%28%42%
1620
16th to endNight
9%3311%29%42%
1685
June1st to 15thNight
7%329%17%60%
1524
16th to endNight
5%1139%78%
1440
July1st to 15thNight
10%235%15%62%
1360
16th to endNight
13%337%17%54%
1543
August1st to 15thNight
7%225%14%67%
1738
16th to endNight
7%236%17%63%
1910
September1st to 15thNight
9%328%17%58%
1863
16th to endNight
3126%25%61%
1980
October1st to 15thNight
9%3411%27%43%
1980
16th to endNight
10%239%28%45%
2388
November1st to 15thNight
10%2418%39%24%
2470
16th to endNight
11%46%17%33%27%
2535
December1st to 15thNight
16%5%8%22%27%18%
2535
16th to endNight
21%6%10%23%26%12%
2802

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
6%12%38%28%11%2
90
16th to endDay
5%9%31%28%21%3
237
February1st to 15thDay
412%29%29%20%3
326
16th to endDay
10%19%32%23%11%1
264
March1st to 15thDay
6%16%31%27%16%
270
16th to endDay
5%20%32%31%8%
288
April1st to 15thDay
9%28%29%19%10%2
269
16th to endDay
8%25%37%23%21
270
May1st to 15thDay
318%40%25%10%2
288
16th to endDay
220%30%34%10%
330
June1st to 15thDay
311%40%34%8%1
315
16th to endDay
6%32%40%15%4
315
July1st to 15thDay
2330%45%14%3
305
16th to endDay
2228%46%14%5%
327
August1st to 15thDay
25%40%35%10%5%
315
16th to endDay
1330%42%13%8%
332
September1st to 15thDay
17%28%45%12%5%
315
16th to endDay
29%26%38%19%3
315
October1st to 15thDay
211%38%34%11%1
315
16th to endDay
5%9%21%32%23%6%
222
November1st to 15thDay
25%21%39%25%5%
135
16th to endDay
29%28%33%24%
135
December1st to 15thDay
35%24%37%25%2
135
16th to endDay
9%10%25%30%20%5%
120
January1st to 15thNight
25%18%38%30%5%
780
16th to endNight
45%18%36%29%5%
832
February1st to 15thNight
36%18%39%26%4
764
16th to endNight
5%8%24%36%22%3
660
March1st to 15thNight
27%22%38%22%6%
720
16th to endNight
410%22%35%25%2
768
April1st to 15thNight
5%11%23%36%20%3
719
16th to endNight
210%25%34%23%3
693
May1st to 15thNight
38%21%41%22%2
540
16th to endNight
38%19%35%31%1
563
June1st to 15thNight
15%18%41%31%2
444
16th to endNight
1112%39%41%3
360
July1st to 15thNight
29%43%42%2
340
16th to endNight
114%44%38%1
514
August1st to 15thNight
115%48%32%1
664
16th to endNight
119%34%46%6%
764
September1st to 15thNight
1111%35%44%5%
720
16th to endNight
412%33%42%6%
716
October1st to 15thNight
2417%37%32%5%
720
16th to endNight
25%12%31%38%10%
768
November1st to 15thNight
1417%34%35%7%
760
16th to endNight
3414%34%37%6%
780
December1st to 15thNight
5%7%14%35%33%4
780
16th to endNight
5%11%14%36%27%4
832
Page generated at 2018-02-23 08:21:35. Version ac04

Copyright 2018 A. Danko


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