Santa Teresa Spring
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Santa Teresa Spring clear sky chart from 2005-11-05 to 2017-10-31.

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
68%
15605
26%
47429
24%
15569
71%
15569
38%
26467

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
64%
716
20%
2389
21%
716
67%
716
31%
1381
January16th to endNight
59%
768
25%
2496
25%
768
62%
768
28%
1513
February1st to 15thNight
59%
699
25%
2271
25%
699
63%
699
28%
1378
February16th to endNight
53%
632
22%
1895
19%
632
58%
632
29%
1188
March1st to 15thNight
56%
720
18%
2022
17%
720
59%
720
27%
1335
March16th to endNight
54%
768
20%
2078
15%
768
58%
768
31%
1340
April1st to 15thNight
54%
719
22%
1799
13%
719
58%
719
33%
1167
April16th to endNight
57%
720
24%
1800
11%
720
61%
720
44%
1055
May1st to 15thNight
71%
647
23%
1727
15%
647
73%
647
43%
983
May16th to endNight
70%
385
24%
1507
25%
385
75%
385
34%
734
June1st to 15thNight
74%
360
25%
1440
27%
360
80%
360
37%
679
June16th to endNight
87%
360
32%
1440
42%
360
89%
360
48%
582
July1st to 15thNight
93%
373
28%
1393
35%
373
93%
373
55%
561
July16th to endNight
87%
564
28%
1593
26%
531
88%
531
44%
826
August1st to 15thNight
81%
578
27%
1651
21%
575
81%
575
42%
904
August16th to endNight
90%
764
33%
1910
22%
764
90%
764
57%
1022
September1st to 15thNight
87%
720
37%
1800
27%
720
88%
720
63%
920
September16th to endNight
82%
716
41%
1953
37%
716
84%
716
59%
963
October1st to 15thNight
74%
720
29%
2160
30%
720
79%
720
47%
1104
October16th to endNight
74%
768
35%
2304
38%
768
77%
768
44%
1213
November1st to 15thNight
70%
700
29%
2193
30%
700
74%
700
42%
1146
November16th to endNight
66%
720
26%
2400
27%
720
69%
720
35%
1305
December1st to 15thNight
57%
720
22%
2520
21%
720
62%
720
25%
1533
December16th to endNight
51%
768
20%
2688
18%
768
57%
768
24%
1635

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
7%413323346%60%
48317
Night
8%413323347%56%
47617
TransparencyDay
26%48%18%24%17%
48004
Night
28%5%10%17%21%16%
47430
SeeingDay
8%8%22%33%20%6%
6185
Night
9%312%30%33%10%
15616

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
14%5%25%322445%48%
1546
16th to endDay
17%5%34413345%45%
1728
February1st to 15thDay
17%6%24423346%42%
1592
16th to endDay
18%7%26%5%23445%39%
1579
March1st to 15thDay
15%6%25%6%45%46%8%36%
1937
16th to endDay
14%6%25%4345%47%41%
2145
April1st to 15thDay
15%7%3442335%7%44%
2149
16th to endDay
8%413323346%58%
2160
May1st to 15thDay
3412212347%64%
2220
16th to endDay
5%424313246%59%
2603
June1st to 15thDay
3423222346%64%
2520
16th to endDay
111111225%80%
2520
July1st to 15thDay
1111222480%
2481
16th to endDay
11112225%80%
2468
August1st to 15thDay
11212235%76%
2298
16th to endDay
11111235%80%
2292
September1st to 15thDay
1211212480%
2160
16th to endDay
2212212245%73%
2004
October1st to 15thDay
4212313347%64%
1800
16th to endDay
6%313323445%61%
1918
November1st to 15thDay
9%42433435%6%52%
1664
16th to endDay
12%5%3332335%6%50%
1557
December1st to 15thDay
16%7%26%434335%42%
1440
16th to endDay
17%8%35%42335%7%39%
1536
January1st to 15thNight
12%5%14325%45%7%47%
2389
16th to endNight
16%5%24323447%46%
2496
February1st to 15thNight
13%6%2442445%7%44%
2259
16th to endNight
17%5%35%32335%7%42%
1895
March1st to 15thNight
15%6%24424447%42%
2022
16th to endNight
12%5%25%42446%8%43%
2078
April1st to 15thNight
13%5%34335%45%6%45%
1799
16th to endNight
6%424413347%57%
1800
May1st to 15thNight
231332235%8%61%
1727
16th to endNight
4323313348%60%
1507
June1st to 15thNight
2212324448%63%
1440
16th to endNight
2212235%75%
1440
July1st to 15thNight
1112337%76%
1476
16th to endNight
232435%8%65%
1701
August1st to 15thNight
213433348%63%
1660
16th to endNight
1122345%7%70%
1910
September1st to 15thNight
111312445%74%
1800
16th to endNight
2212212236%73%
1953
October1st to 15thNight
5%312213345%65%
2160
16th to endNight
5%313323346%62%
2304
November1st to 15thNight
7%423314347%57%
2193
16th to endNight
7%424424447%52%
2400
December1st to 15thNight
13%7%35%423346%46%
2520
16th to endNight
17%6%2342445%5%43%
2688

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
35%5%11%19%16%10%
1546
16th to endDay
41%5%7%13%19%13%
1728
February1st to 15thDay
40%48%19%19%6%
1592
16th to endDay
46%5%8%21%14%3
1579
March1st to 15thDay
42%6%12%17%15%5%
1937
16th to endDay
40%8%13%18%16%3
2145
April1st to 15thDay
39%5%12%19%19%2
2149
16th to endDay
27%5%13%24%21%8%
2160
May1st to 15thDay
20%410%28%29%7%
2220
16th to endDay
28%411%25%23%6%
2607
June1st to 15thDay
22%5%10%22%23%14%
2520
16th to endDay
11%3416%34%28%
2520
July1st to 15thDay
11%338%24%48%
2335
16th to endDay
10%3310%29%42%
2313
August1st to 15thDay
15%3311%29%36%
2282
16th to endDay
11%2412%36%32%
2292
September1st to 15thDay
11%2314%33%34%
2160
16th to endDay
15%2425%33%18%
2004
October1st to 15thDay
19%38%20%23%24%
1800
16th to endDay
23%410%18%23%18%
1918
November1st to 15thDay
30%410%22%23%8%
1664
16th to endDay
33%410%17%28%4
1557
December1st to 15thDay
42%6%8%17%19%6%
1440
16th to endDay
43%5%11%16%16%6%
1536
January1st to 15thNight
33%5%12%20%18%9%
2389
16th to endNight
37%5%10%12%17%16%
2496
February1st to 15thNight
38%410%19%19%8%
2271
16th to endNight
39%414%23%14%3
1895
March1st to 15thNight
39%7%11%18%14%8%
2022
16th to endNight
37%5%13%18%17%7%
2078
April1st to 15thNight
35%6%13%23%17%3
1799
16th to endNight
25%5%14%23%21%9%
1800
May1st to 15thNight
24%6%10%18%27%11%
1728
16th to endNight
25%6%14%23%24%6%
1507
June1st to 15thNight
22%6%12%18%20%19%
1440
16th to endNight
15%4313%28%32%
1440
July1st to 15thNight
13%47%7%20%45%
1393
16th to endNight
22%6%8%8%18%36%
1593
August1st to 15thNight
25%6%5%9%20%32%
1651
16th to endNight
18%46%8%31%30%
1910
September1st to 15thNight
15%25%9%28%37%
1800
16th to endNight
16%3419%33%22%
1953
October1st to 15thNight
22%47%19%20%25%
2160
16th to endNight
24%46%20%23%20%
2304
November1st to 15thNight
25%412%22%25%10%
2193
16th to endNight
29%410%20%24%10%
2400
December1st to 15thNight
39%5%8%17%20%8%
2520
16th to endNight
39%5%14%15%17%7%
2688

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
21%12%22%27%13%3
174
16th to endDay
19%8%23%25%18%4
256
February1st to 15thDay
17%12%24%23%19%3
239
16th to endDay
20%12%26%25%13%2
238
March1st to 15thDay
16%15%27%21%14%4
270
16th to endDay
15%15%32%25%10%1
288
April1st to 15thDay
18%19%30%20%10%
269
16th to endDay
10%20%31%24%10%2
270
May1st to 15thDay
10%13%35%27%9%2
288
16th to endDay
6%12%26%30%19%4
330
June1st to 15thDay
6%9%33%32%13%5%
315
16th to endDay
1220%44%22%8%
315
July1st to 15thDay
12%43%34%8%
305
16th to endDay
18%49%28%12%
327
August1st to 15thDay
314%41%31%8%
315
16th to endDay
110%43%30%12%
332
September1st to 15thDay
1214%45%26%10%
315
16th to endDay
5%5%18%37%23%8%
315
October1st to 15thDay
49%25%35%19%5%
315
16th to endDay
8%325%33%22%7%
336
November1st to 15thDay
7%7%16%21%32%13%
170
16th to endDay
8%11%25%31%18%3
79
December1st to 15thDay
15%18%23%33%10%
60
16th to endDay
14%12%7%34%23%7%
64
January1st to 15thNight
13%113%32%29%10%
720
16th to endNight
18%311%29%26%11%
768
February1st to 15thNight
15%413%30%27%8%
704
16th to endNight
17%5%16%33%20%6%
632
March1st to 15thNight
15%5%15%28%27%7%
720
16th to endNight
14%6%18%31%24%4
768
April1st to 15thNight
13%8%17%35%21%4
719
16th to endNight
7%7%21%31%23%8%
720
May1st to 15thNight
3118%36%31%8%
648
16th to endNight
5%313%33%35%8%
386
June1st to 15thNight
3115%37%36%5%
360
16th to endNight
2438%48%5%
360
July1st to 15thNight
2221%58%14%
373
16th to endNight
15%20%49%23%
564
August1st to 15thNight
26%27%50%11%
578
16th to endNight
1426%51%15%
764
September1st to 15thNight
2428%48%15%
720
16th to endNight
319%30%40%14%
716
October1st to 15thNight
7%310%33%32%14%
720
16th to endNight
7%111%27%31%20%
768
November1st to 15thNight
8%212%32%30%13%
700
16th to endNight
9%212%34%29%11%
720
December1st to 15thNight
16%412%32%25%8%
720
16th to endNight
19%5%16%31%22%4
768
Page generated at 2017-11-01 14:23:36. Version ac04

Copyright 2017 A. Danko


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