This page made possible by the sponsorship of: George Varga - MTRP Volunteer.

Mission Trails Regional Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mission Trails Regional Park clear sky chart from 2005-11-05 to 2017-09-10.

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
74%
16235
30%
46902
28%
16191
75%
16191
43%
25802

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
30%
2312
31%
716
76%
716
42%
1195
January16th to endNight
68%
768
33%
2304
32%
768
72%
768
40%
1283
February1st to 15thNight
72%
698
32%
2106
34%
698
75%
698
42%
1127
February16th to endNight
63%
632
27%
1895
31%
632
64%
632
31%
1160
March1st to 15thNight
70%
720
28%
2160
31%
720
72%
720
40%
1194
March16th to endNight
71%
768
26%
2037
24%
768
72%
768
41%
1213
April1st to 15thNight
67%
719
25%
1799
19%
719
67%
719
42%
1102
April16th to endNight
70%
720
27%
1800
19%
720
71%
720
44%
1087
May1st to 15thNight
69%
590
25%
1670
19%
590
69%
590
37%
1020
May16th to endNight
66%
561
22%
1685
18%
561
66%
561
34%
1044
June1st to 15thNight
70%
540
20%
1620
18%
540
70%
540
36%
993
June16th to endNight
83%
540
30%
1620
27%
540
83%
540
56%
789
July1st to 15thNight
83%
510
23%
1530
20%
510
83%
510
45%
831
July16th to endNight
80%
643
27%
1666
20%
604
79%
604
44%
941
August1st to 15thNight
80%
717
29%
1790
19%
713
81%
713
53%
988
August16th to endNight
84%
764
36%
1910
26%
764
84%
764
58%
1021
September1st to 15thNight
83%
700
33%
1817
28%
700
83%
700
54%
980
September16th to endNight
84%
656
41%
1815
40%
656
85%
656
62%
855
October1st to 15thNight
78%
660
34%
1815
33%
660
80%
660
48%
973
October16th to endNight
74%
704
35%
2100
38%
704
76%
704
45%
1092
November1st to 15thNight
80%
700
33%
2275
39%
700
81%
700
50%
1072
November16th to endNight
77%
720
33%
2340
38%
720
78%
720
44%
1176
December1st to 15thNight
67%
720
31%
2340
34%
720
69%
720
36%
1279
December16th to endNight
66%
768
31%
2496
32%
768
70%
768
36%
1387

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
5%313323346%62%
47710
Night
6%5%23423347%56%
47110
TransparencyDay
23%26%17%25%24%
47413
Night
28%26%16%22%23%
46909
SeeingDay
7%5%24%40%17%4
5907
Night
8%15%31%40%12%
16247

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
8%314323345%58%
1623
16th to endDay
10%423322346%55%
1920
February1st to 15thDay
7%32341345%5%58%
1751
16th to endDay
12%425%415%45%8%45%
1579
March1st to 15thDay
6%42322435%9%56%
1800
16th to endDay
6%223324348%57%
2184
April1st to 15thDay
7%5%2342435%6%55%
2149
16th to endDay
6%312212247%65%
2160
May1st to 15thDay
6%413323336%59%
2278
16th to endDay
5%5%13223236%62%
2429
June1st to 15thDay
5%6%23323235%61%
2340
16th to endDay
21221333474%
2340
July1st to 15thDay
25%1242345%7%61%
2340
16th to endDay
331231345%8%61%
2384
August1st to 15thDay
1313213225%72%
2160
16th to endDay
1212222347%70%
2292
September1st to 15thDay
1213213336%70%
2030
16th to endDay
22231232474%
1815
October1st to 15thDay
4423423345%61%
1815
16th to endDay
6%41221223468%
1769
November1st to 15thDay
5%213314346%64%
1584
16th to endDay
5%313314346%61%
1620
December1st to 15thDay
8%312423448%53%
1620
16th to endDay
12%323423347%53%
1728
January1st to 15thNight
7%313323446%58%
2312
16th to endNight
10%414213336%56%
2304
February1st to 15thNight
7%414322346%57%
2101
16th to endNight
13%6%245%23445%47%
1895
March1st to 15thNight
8%5%24313448%53%
2160
16th to endNight
7%6%2332445%8%51%
2037
April1st to 15thNight
10%7%23322347%51%
1799
16th to endNight
7%7%14313435%56%
1800
May1st to 15thNight
6%10%34433249%46%
1670
16th to endNight
9%10%35%423338%45%
1684
June1st to 15thNight
5%10%35%43436%8%43%
1620
16th to endNight
15%235%13447%60%
1620
July1st to 15thNight
18%135%34448%53%
1620
16th to endNight
35%244345%6%8%51%
1780
August1st to 15thNight
26%14423349%56%
1800
16th to endNight
15%13223338%64%
1910
September1st to 15thNight
15%12423437%62%
1817
16th to endNight
2311311226%70%
1815
October1st to 15thNight
4313423347%61%
1815
16th to endNight
6%413322236%61%
2100
November1st to 15thNight
4412313435%66%
2275
16th to endNight
5%413423347%58%
2340
December1st to 15thNight
9%425%423347%53%
2340
16th to endNight
12%414313345%55%
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
28%35%13%22%27%
1624
16th to endDay
30%37%15%14%29%
1920
February1st to 15thDay
26%25%14%22%27%
1751
16th to endDay
37%46%16%24%12%
1579
March1st to 15thDay
26%26%20%21%21%
1800
16th to endDay
26%38%25%19%15%
2184
April1st to 15thDay
29%36%24%26%9%
2149
16th to endDay
20%29%24%24%19%
2160
May1st to 15thDay
25%26%22%25%16%
2278
16th to endDay
23%26%24%32%10%
2432
June1st to 15thDay
25%15%18%28%20%
2340
16th to endDay
13%127%29%44%
2340
July1st to 15thDay
21%2414%26%30%
2201
16th to endDay
19%411%24%28%12%
2236
August1st to 15thDay
16%1318%34%25%
2146
16th to endDay
14%2316%34%27%
2292
September1st to 15thDay
15%2312%35%30%
2030
16th to endDay
13%2213%35%32%
1815
October1st to 15thDay
25%2317%25%24%
1815
16th to endDay
21%1313%22%36%
1769
November1st to 15thDay
21%27%16%17%35%
1584
16th to endDay
22%35%16%19%33%
1620
December1st to 15thDay
28%39%15%17%25%
1620
16th to endDay
31%37%16%22%18%
1728
January1st to 15thNight
26%25%14%20%29%
2312
16th to endNight
30%27%12%14%31%
2304
February1st to 15thNight
28%27%15%20%27%
2112
16th to endNight
39%25%14%22%15%
1895
March1st to 15thNight
30%18%18%17%22%
2160
16th to endNight
30%39%19%21%13%
2037
April1st to 15thNight
32%27%24%21%10%
1799
16th to endNight
30%27%21%19%18%
1800
May1st to 15thNight
34%37%20%17%16%
1671
16th to endNight
38%28%21%16%12%
1685
June1st to 15thNight
36%28%16%22%13%
1620
16th to endNight
20%1211%28%36%
1620
July1st to 15thNight
26%2413%26%26%
1530
16th to endNight
26%49%24%25%9%
1666
August1st to 15thNight
23%1421%30%17%
1790
16th to endNight
19%2413%32%27%
1910
September1st to 15thNight
21%3312%31%27%
1817
16th to endNight
16%1212%36%31%
1815
October1st to 15thNight
24%2419%24%23%
1815
16th to endNight
25%2312%21%35%
2100
November1st to 15thNight
21%16%17%16%36%
2275
16th to endNight
25%26%16%17%31%
2340
December1st to 15thNight
31%27%14%18%23%
2340
16th to endNight
31%38%15%18%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
23%120%35%17%
102
16th to endDay
13%9%30%36%8%1
288
February1st to 15thDay
8%7%31%36%14%1
266
16th to endDay
13%11%37%26%8%1
238
March1st to 15thDay
8%9%30%33%13%4
270
16th to endDay
410%32%38%10%3
288
April1st to 15thDay
9%10%39%27%9%3
269
16th to endDay
5%12%39%30%7%4
270
May1st to 15thDay
12%9%31%34%10%2
288
16th to endDay
12%6%32%33%14%
330
June1st to 15thDay
6%226%45%16%3
315
16th to endDay
114%51%25%6%
315
July1st to 15thDay
5%18%48%29%6%
305
16th to endDay
6%450%29%9%
327
August1st to 15thDay
311%54%24%6%
315
16th to endDay
48%53%26%6%
332
September1st to 15thDay
4120%56%13%4
294
16th to endDay
3225%49%12%5%
255
October1st to 15thDay
5%6%40%32%12%1
255
16th to endDay
11%325%35%20%4
219
November1st to 15thDay
46%13%30%34%11%
90
16th to endDay
6%10%21%33%25%3
90
December1st to 15thDay
4415%36%32%6%
90
16th to endDay
18%415%38%20%2
96
January1st to 15thNight
8%28%39%29%12%
720
16th to endNight
13%27%37%30%8%
768
February1st to 15thNight
9%26%36%34%10%
704
16th to endNight
15%28%42%26%5%
632
March1st to 15thNight
10%36%40%32%6%
720
16th to endNight
10%26%36%36%7%
768
April1st to 15thNight
13%29%39%30%5%
719
16th to endNight
10%37%37%31%9%
720
May1st to 15thNight
10%17%35%36%7%
591
16th to endNight
13%28%31%38%4
563
June1st to 15thNight
8%8%38%38%5%
540
16th to endNight
2229%57%7%
540
July1st to 15thNight
5%115%65%12%
510
16th to endNight
4212%58%21%
643
August1st to 15thNight
4114%59%19%
717
16th to endNight
318%56%29%
764
September1st to 15thNight
4117%58%18%
700
16th to endNight
5%127%48%16%
656
October1st to 15thNight
6%15%36%41%9%
660
16th to endNight
8%15%29%35%18%
704
November1st to 15thNight
6%1435%37%15%
700
16th to endNight
7%5%33%36%16%
720
December1st to 15thNight
11%29%36%29%12%
720
16th to endNight
14%19%35%27%10%
768
Page generated at 2017-09-11 16:35:15. Version ac04

Copyright 2017 A. Danko


Mission Trails Regional Park Clear Sky Chart | Charts Home