Springville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Springville clear sky chart from 2005-11-06 to 2024-01-14.

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
66%
23901
31%
74582
26%
23851
72%
23851
45%
38268

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 10thNight
47%
757
21%
2646
17%
756
55%
756
28%
1533
January11th to 20thNight
53%
734
28%
2468
22%
734
64%
734
35%
1342
January21st to endNight
47%
792
28%
2562
22%
792
58%
792
31%
1473
February1st to 10thNight
50%
720
28%
2160
22%
720
59%
720
33%
1287
February11th to 20thNight
53%
700
29%
2099
25%
700
62%
700
39%
1169
February21st to endNight
49%
592
22%
1776
20%
592
55%
592
29%
1106
March1st to 10thNight
52%
720
20%
2160
17%
720
58%
720
30%
1336
March11th to 20thNight
56%
720
20%
2080
17%
720
61%
720
34%
1254
March21st to endNight
52%
792
19%
1990
12%
792
57%
792
34%
1289
April1st to 10thNight
56%
720
25%
1800
14%
720
61%
720
41%
1103
April11th to 20thNight
55%
711
28%
1779
13%
711
61%
711
44%
1044
April21st to endNight
61%
720
28%
1800
13%
720
65%
720
53%
984
May1st to 10thNight
63%
640
29%
1720
17%
640
67%
640
50%
915
May11th to 20thNight
66%
531
34%
1595
26%
531
70%
531
53%
752
May21st to endNight
63%
506
29%
1670
23%
506
70%
506
48%
770
June1st to 10thNight
76%
360
33%
1440
36%
360
82%
360
51%
559
June11th to 20thNight
81%
360
38%
1440
43%
360
88%
360
66%
475
June21st to endNight
83%
360
41%
1440
45%
360
91%
360
77%
430
July1st to 10thNight
92%
350
40%
1400
49%
350
93%
350
75%
437
July11th to 20thNight
93%
348
42%
1392
51%
348
94%
348
68%
457
July21st to endNight
87%
544
38%
1631
33%
515
89%
515
64%
689
August1st to 10thNight
86%
716
37%
1780
24%
712
87%
712
77%
818
August11th to 20thNight
92%
712
42%
1780
25%
712
93%
712
86%
772
August21st to endNight
90%
792
45%
1980
29%
792
91%
792
82%
883
September1st to 10thNight
90%
720
46%
1800
34%
720
92%
720
84%
790
September11th to 20thNight
85%
720
46%
1890
38%
720
88%
720
79%
824
September21st to endNight
82%
720
45%
1980
39%
720
89%
720
75%
849
October1st to 10thNight
76%
720
36%
2003
31%
720
82%
720
60%
969
October11th to 20thNight
74%
720
38%
2160
37%
720
80%
720
57%
993
October21st to endNight
73%
792
41%
2416
39%
792
80%
792
58%
1098
November1st to 10thNight
68%
740
32%
2405
33%
740
73%
740
44%
1189
November11th to 20thNight
64%
760
32%
2470
27%
760
75%
760
46%
1187
November21st to endNight
58%
760
29%
2470
25%
760
66%
760
37%
1341
December1st to 10thNight
52%
760
27%
2470
20%
760
63%
760
34%
1381
December11th to 20thNight
50%
760
23%
3184
21%
759
59%
759
21%
2022
December21st to endNight
46%
832
15%
4746
20%
817
54%
817
15%
2748

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
6%423323346%64%
74815
Night
7%413323346%63%
74952
TransparencyDay
22%5%7%20%27%19%
74529
Night
23%5%8%21%26%17%
74761
SeeingDay
8%12%30%35%12%3
14193
Night
9%319%38%27%5%
23914

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 10thDay
13%7%24425%46%7%46%
1519
11th to 20thDay
10%6%25%4245%7%8%50%
1562
21st to endDay
12%8%35%5%25%5%46%44%
1791
February1st to 10thDay
13%7%24423347%52%
1800
11th to 20thDay
11%9%2442345%7%50%
1750
21st to endDay
16%10%37%423336%42%
1480
March1st to 10thDay
14%10%45%5%25%45%6%40%
1800
11th to 20thDay
9%9%25%5%4445%8%44%
1876
21st to endDay
11%10%36%6%24345%45%
2366
April1st to 10thDay
10%7%35%423347%52%
2160
11th to 20thDay
9%6%2442345%6%54%
2129
21st to endDay
8%6%1442345%7%57%
2160
May1st to 10thDay
6%5%13324346%63%
2236
11th to 20thDay
5%41332335%6%65%
2301
21st to endDay
6%323323446%65%
2602
June1st to 10thDay
331332335%6%68%
2520
11th to 20thDay
111111222484%
2520
21st to endDay
111211213384%
2520
July1st to 10thDay
11121223482%
2520
11th to 20thDay
2111213335%80%
2520
21st to endDay
2213212336%75%
2583
August1st to 10thDay
121121222384%
2149
11th to 20thDay
11121223483%
2122
21st to endDay
11111213485%
2376
September1st to 10thDay
111112225%83%
2160
11th to 20thDay
111211122385%
2070
21st to endDay
111221323481%
1980
October1st to 10thDay
4313322346%69%
1954
11th to 20thDay
331332233472%
1800
21st to endDay
5%213222345%71%
1939
November1st to 10thDay
6%6%14323346%61%
1674
11th to 20thDay
6%41232335%7%64%
1710
21st to endDay
7%5%2442445%7%57%
1710
December1st to 10thDay
10%42432346%8%54%
1710
11th to 20thDay
15%9%35%5%3346%7%38%
1952
21st to endDay
12%8%35%5%35%5%5%8%40%
2794
January1st to 10thNight
14%7%234245%5%8%46%
2646
11th to 20thNight
8%5%243245%6%8%54%
2468
21st to endNight
13%6%2442435%7%51%
2562
February1st to 10thNight
12%8%35%423347%51%
2160
11th to 20thNight
11%7%23223447%55%
2098
21st to endNight
14%9%35%323447%47%
1776
March1st to 10thNight
10%8%34435%5%6%7%46%
2160
11th to 20thNight
11%6%1333446%8%49%
2080
21st to endNight
13%8%24434436%49%
1990
April1st to 10thNight
9%5%2432335%7%57%
1800
11th to 20thNight
9%323323436%61%
1779
21st to endNight
7%413212347%67%
1800
May1st to 10thNight
6%412223247%66%
1720
11th to 20thNight
6%213313235%71%
1594
21st to endNight
6%313222235%71%
1670
June1st to 10thNight
5%212222246%73%
1440
11th to 20thNight
111121133383%
1440
21st to endNight
1111222488%
1440
July1st to 10thNight
1111123486%
1440
11th to 20thNight
121111213483%
1440
21st to endNight
221232233478%
1726
August1st to 10thNight
121111112484%
1790
11th to 20thNight
1111122488%
1780
21st to endNight
11111122388%
1980
September1st to 10thNight
2111112289%
1800
11th to 20thNight
11111222386%
1890
21st to endNight
11121223383%
1980
October1st to 10thNight
321222333474%
2003
11th to 20thNight
321322344473%
2160
21st to endNight
431221223476%
2416
November1st to 10thNight
6%5%23313346%64%
2405
11th to 20thNight
5%414323348%62%
2470
21st to endNight
7%5%24424446%57%
2470
December1st to 10thNight
9%5%2443445%6%54%
2470
11th to 20thNight
17%7%25%4345%6%7%40%
3247
21st to endNight
9%7%36%7%45%6%6%8%39%
4862

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 10thDay
35%5%12%24%19%4
1519
11th to 20thDay
31%6%10%22%19%11%
1562
21st to endDay
41%5%11%17%19%7%
1791
February1st to 10thDay
33%49%23%21%10%
1800
11th to 20thDay
34%5%9%20%23%9%
1760
21st to endDay
45%6%9%22%17%2
1480
March1st to 10thDay
41%9%8%19%17%6%
1800
11th to 20thDay
34%10%12%21%19%4
1876
21st to endDay
38%8%14%23%14%3
2366
April1st to 10thDay
32%7%12%26%17%5%
2160
11th to 20thDay
29%6%13%24%21%6%
2132
21st to endDay
26%6%10%35%21%2
2160
May1st to 10thDay
21%7%10%27%32%4
2236
11th to 20thDay
19%6%9%31%30%6%
2304
21st to endDay
20%6%7%36%27%3
2602
June1st to 10thDay
16%5%10%23%34%12%
2520
11th to 20thDay
7%45%18%43%24%
2520
21st to endDay
7%3210%41%37%
2520
July1st to 10thDay
8%4210%29%48%
2451
11th to 20thDay
9%3312%33%40%
2445
21st to endDay
12%4415%32%32%
2439
August1st to 10thDay
9%338%35%42%
2135
11th to 20thDay
6%2211%38%40%
2122
21st to endDay
6%219%38%42%
2376
September1st to 10thDay
6%3310%34%43%
2160
11th to 20thDay
7%3219%41%29%
2070
21st to endDay
8%3321%39%26%
1980
October1st to 10thDay
17%5%6%19%25%27%
1954
11th to 20thDay
16%4419%31%26%
1800
21st to endDay
16%5%5%18%31%25%
1939
November1st to 10thDay
23%6%7%19%28%17%
1674
11th to 20thDay
23%49%23%27%15%
1710
21st to endDay
28%6%7%16%25%17%
1710
December1st to 10thDay
28%5%11%19%21%14%
1710
11th to 20thDay
43%8%10%15%15%9%
1952
21st to endDay
41%7%12%21%14%5%
2794
January1st to 10thNight
36%5%11%23%20%5%
2646
11th to 20thNight
28%7%10%25%18%12%
2468
21st to endNight
34%5%11%19%21%10%
2562
February1st to 10thNight
35%5%6%24%21%10%
2160
11th to 20thNight
28%5%8%22%26%10%
2099
21st to endNight
38%5%11%23%18%3
1776
March1st to 10thNight
36%7%12%21%18%5%
2160
11th to 20thNight
32%7%14%23%19%5%
2080
21st to endNight
35%8%15%27%13%3
1990
April1st to 10thNight
28%7%14%27%16%7%
1800
11th to 20thNight
23%8%13%28%21%6%
1779
21st to endNight
20%5%14%38%21%2
1800
May1st to 10thNight
20%5%11%31%28%5%
1720
11th to 20thNight
17%49%32%33%4
1595
21st to endNight
18%5%10%32%32%3
1670
June1st to 10thNight
15%310%23%37%11%
1440
11th to 20thNight
8%37%18%39%25%
1440
21st to endNight
6%1311%47%32%
1440
July1st to 10thNight
5%2311%32%47%
1400
11th to 20thNight
8%2414%31%40%
1392
21st to endNight
12%36%17%28%34%
1631
August1st to 10thNight
9%2311%34%42%
1780
11th to 20thNight
42216%39%36%
1780
21st to endNight
6%2211%41%39%
1980
September1st to 10thNight
5%2212%31%49%
1800
11th to 20thNight
7%2417%44%26%
1890
21st to endNight
8%2322%37%28%
1980
October1st to 10thNight
15%5%6%19%29%27%
2003
11th to 20thNight
15%45%20%31%26%
2160
21st to endNight
15%4421%31%25%
2416
November1st to 10thNight
22%5%8%19%27%19%
2405
11th to 20thNight
21%5%10%20%26%19%
2470
21st to endNight
28%6%8%16%26%16%
2470
December1st to 10thNight
30%6%8%19%22%14%
2470
11th to 20thNight
40%9%9%17%16%8%
3247
21st to endNight
38%9%10%23%14%4
4862

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 10thDay
22%12%32%27%7%1
180
11th to 20thDay
15%10%30%30%13%3
264
21st to endDay
16%8%33%29%12%2
378
February1st to 10thDay
15%10%32%29%11%2
420
11th to 20thDay
16%15%36%24%6%2
415
21st to endDay
18%16%36%24%7%
346
March1st to 10thDay
19%19%35%22%5%1
420
11th to 20thDay
16%20%32%25%7%1
420
21st to endDay
18%24%33%22%3
462
April1st to 10thDay
15%20%31%25%7%1
420
11th to 20thDay
15%25%31%24%5%1
412
21st to endDay
9%20%33%26%10%2
420
May1st to 10thDay
9%22%32%26%10%1
423
11th to 20thDay
9%13%34%33%9%2
448
21st to endDay
11%16%29%31%10%4
485
June1st to 10thDay
312%30%38%12%5%
450
11th to 20thDay
213%27%40%14%5%
450
21st to endDay
110%32%38%16%4
450
July1st to 10thDay
2226%48%16%6%
446
11th to 20thDay
1116%55%19%8%
444
21st to endDay
2116%57%17%7%
487
August1st to 10thDay
35%31%42%13%5%
447
11th to 20thDay
1328%49%13%6%
437
21st to endDay
2228%50%15%3
495
September1st to 10thDay
3430%45%14%3
450
11th to 20thDay
19%35%44%9%1
450
21st to endDay
311%31%41%14%
450
October1st to 10thDay
414%32%38%11%
450
11th to 20thDay
410%33%40%11%1
450
21st to endDay
6%12%28%37%16%1
454
November1st to 10thDay
6%13%30%32%16%2
270
11th to 20thDay
7%9%31%31%17%4
270
21st to endDay
11%13%27%33%13%3
270
December1st to 10thDay
13%11%34%33%8%1
270
11th to 20thDay
15%8%28%31%18%1
192
21st to endDay
24%13%28%23%11%1
198
January1st to 10thNight
17%6%27%30%17%4
760
11th to 20thNight
10%428%40%16%2
734
21st to endNight
17%327%35%15%3
792
February1st to 10thNight
16%425%38%16%2
720
11th to 20thNight
15%425%34%18%4
704
21st to endNight
18%6%22%37%15%2
592
March1st to 10thNight
15%6%23%38%17%2
720
11th to 20thNight
13%5%22%33%22%5%
720
21st to endNight
16%7%21%37%19%1
792
April1st to 10thNight
12%424%40%19%2
720
11th to 20thNight
10%7%23%33%24%2
711
21st to endNight
9%5%24%35%25%3
720
May1st to 10thNight
8%423%38%26%1
640
11th to 20thNight
7%419%39%28%3
531
21st to endNight
8%6%19%38%26%2
508
June1st to 10thNight
6%213%43%34%1
360
11th to 20thNight
1113%48%32%5%
360
21st to endNight
1113%41%39%6%
360
July1st to 10thNight
15%35%53%6%
350
11th to 20thNight
1232%55%9%
348
21st to endNight
115%30%49%14%
544
August1st to 10thNight
218%41%42%7%
716
11th to 20thNight
15%36%46%12%
712
21st to endNight
16%30%53%10%
792
September1st to 10thNight
115%36%45%11%
720
11th to 20thNight
1112%45%34%8%
720
21st to endNight
2113%38%40%6%
720
October1st to 10thNight
4116%48%28%4
720
11th to 20thNight
4216%41%31%6%
720
21st to endNight
4218%38%31%7%
792
November1st to 10thNight
9%416%39%26%5%
740
11th to 20thNight
8%320%42%24%4
760
21st to endNight
10%225%41%19%4
760
December1st to 10thNight
11%428%36%18%3
760
11th to 20thNight
17%424%39%14%2
760
21st to endNight
17%6%26%36%12%3
836
Page generated at 2024-01-11 01:22:42. Version ac07

Copyright 2024 Attilla Danko


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