Martis Creek Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Martis Creek Campground clear sky chart from 2005-11-06 to 2024-04-10.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	3 7% 3 5% 4 2 4 4 5% 6% 58%	83243
	Night	2 7% 3 5% 5% 3 4 4 5% 7% 54%	85602
Transparency	Day	26% 7% 10% 20% 22% 15%	82952
	Night	28% 8% 11% 20% 21% 12%	85415
Seeing	Day	14% 20% 30% 22% 11% 2	14233
	Night	11% 13% 22% 30% 20% 4	23713

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	2 12% 6% 7% 5% 3 4 4 6% 8% 42%	2539
	11th to 20th	Day	2 12% 4 6% 7% 4 6% 6% 6% 7% 42%	2617
	21st to end	Day	5% 16% 5% 8% 6% 3 5% 5% 5% 6% 35%	3146
February	1st to 10th	Day	3 10% 4 6% 5% 3 5% 4 5% 6% 48%	1710
	11th to 20th	Day	2 9% 6% 7% 6% 3 3 5% 6% 7% 47%	1835
	21st to end	Day	1 10% 5% 7% 5% 2 4 4 6% 7% 46%	1570
March	1st to 10th	Day	2 16% 11% 14% 6% 4 5% 4 5% 6% 29%	3138
	11th to 20th	Day	2 8% 4 4 4 2 3 4 4 6% 59%	3458
	21st to end	Day	1 14% 6% 8% 6% 4 4 6% 5% 7% 40%	4058
April	1st to 10th	Day	4 10% 4 7% 5% 2 4 4 6% 8% 46%	2270
	11th to 20th	Day	3 9% 4 6% 4 2 5% 4 5% 7% 51%	2129
	21st to end	Day	4 9% 3 5% 4 2 3 3 6% 7% 56%	2160
May	1st to 10th	Day	5% 7% 2 4 4 2 3 4 5% 8% 58%	2255
	11th to 20th	Day	4 7% 2 5% 4 2 4 4 4 6% 57%	2454
	21st to end	Day	7% 8% 3 6% 6% 3 4 4 4 7% 48%	2723
June	1st to 10th	Day	4 4 2 4 4 3 4 4 5% 8% 58%	2520
	11th to 20th	Day	2 3 1 3 2 2 3 3 3 5% 75%	2520
	21st to end	Day	2 3 1 2 2 1 2 3 3 5% 76%	2520
July	1st to 10th	Day	1 1 1 2 1 2 2 3 4 82%	2520
	11th to 20th	Day	1 1 1 2 2 1 2 2 3 5% 80%	2520
	21st to end	Day	2 1 1 3 2 2 3 3 5% 4 73%	2669
August	1st to 10th	Day	3 2 1 3 2 2 2 3 4 4 75%	2320
	11th to 20th	Day	1 1 2 2 2 3 3 3 5% 79%	2122
	21st to end	Day	1 1 1 1 1 2 2 2 3 85%	2376
September	1st to 10th	Day	2 1 1 2 1 2 2 3 4 81%	2160
	11th to 20th	Day	2 3 1 3 3 1 3 2 4 5% 73%	2141
	21st to end	Day	3 4 1 2 2 1 2 2 4 5% 74%	1980
October	1st to 10th	Day	5% 5% 2 4 3 2 3 4 4 4 66%	1814
	11th to 20th	Day	3 4 2 4 3 1 3 3 4 5% 68%	1800
	21st to end	Day	3 4 1 3 3 2 2 3 4 7% 66%	1943
November	1st to 10th	Day	4 7% 3 4 4 2 4 5% 4 7% 55%	1674
	11th to 20th	Day	2 6% 2 3 4 2 5% 6% 6% 10% 54%	1710
	21st to end	Day	2 6% 3 5% 5% 2 3 5% 6% 8% 54%	1630
December	1st to 10th	Day	3 9% 4 6% 6% 3 4 4 6% 8% 47%	1520
	11th to 20th	Day	6% 14% 6% 8% 6% 3 6% 6% 6% 7% 33%	1928
	21st to end	Day	3 8% 3 7% 6% 3 5% 5% 8% 11% 41%	2794
January	1st to 10th	Night	2 6% 4 7% 6% 4 5% 7% 8% 9% 43%	4406
	11th to 20th	Night	1 12% 5% 8% 6% 3 6% 6% 6% 7% 38%	4331
	21st to end	Night	3 17% 5% 7% 6% 4 5% 6% 6% 5% 35%	4521
February	1st to 10th	Night	2 8% 3 8% 6% 4 5% 5% 6% 7% 46%	2470
	11th to 20th	Night	1 8% 4 6% 6% 4 6% 6% 7% 9% 46%	2232
	21st to end	Night	2 8% 4 7% 6% 3 5% 5% 5% 8% 47%	1884
March	1st to 10th	Night	1 13% 8% 11% 6% 4 5% 5% 6% 8% 33%	3736
	11th to 20th	Night	1 10% 4 5% 4 3 3 4 5% 6% 56%	3508
	21st to end	Night	2 14% 7% 9% 8% 4 6% 6% 6% 6% 32%	3594
April	1st to 10th	Night	3 6% 3 6% 5% 3 5% 6% 6% 8% 48%	1900
	11th to 20th	Night	3 8% 3 4 5% 2 4 5% 5% 7% 54%	1779
	21st to end	Night	4 6% 3 3 4 3 3 4 4 6% 59%	1800
May	1st to 10th	Night	4 6% 2 4 3 2 4 4 5% 5% 61%	1702
	11th to 20th	Night	2 6% 2 4 4 4 4 3 5% 8% 58%	1434
	21st to end	Night	5% 7% 3 4 4 2 4 4 4 8% 54%	1552
June	1st to 10th	Night	4 4 1 5% 3 2 4 4 4 8% 61%	1440
	11th to 20th	Night	1 2 1 1 2 2 2 3 4 5% 78%	1440
	21st to end	Night	2 2 1 3 2 1 3 3 3 4 76%	1440
July	1st to 10th	Night	1 1 1 2 2 2 2 2 2 4 82%	1440
	11th to 20th	Night	2 1 1 2 2 1 2 2 3 4 80%	1440
	21st to end	Night	4 2 1 2 3 1 3 3 3 4 74%	1643
August	1st to 10th	Night	3 2 1 2 4 2 3 3 4 4 72%	1618
	11th to 20th	Night	2 2 1 2 2 1 2 3 3 4 77%	1780
	21st to end	Night	1 1 2 2 1 1 2 3 3 82%	1980
September	1st to 10th	Night	2 1 1 1 1 1 2 2 2 4 84%	1800
	11th to 20th	Night	2 2 1 2 2 1 2 2 3 5% 78%	1818
	21st to end	Night	2 2 1 3 2 2 2 3 4 4 75%	1980
October	1st to 10th	Night	4 4 2 3 3 2 2 3 3 4 70%	2142
	11th to 20th	Night	3 2 1 3 3 2 2 2 4 7% 71%	2160
	21st to end	Night	2 4 1 3 2 2 2 4 4 7% 68%	2412
November	1st to 10th	Night	3 6% 3 4 4 3 4 4 5% 7% 56%	2405
	11th to 20th	Night	2 6% 2 4 4 3 3 5% 6% 9% 57%	2470
	21st to end	Night	2 5% 3 5% 6% 3 5% 5% 5% 8% 54%	2547
December	1st to 10th	Night	3 6% 4 5% 5% 3 5% 5% 6% 8% 49%	2660
	11th to 20th	Night	4 15% 5% 8% 6% 3 6% 5% 6% 9% 34%	3276
	21st to end	Night	2 9% 5% 8% 8% 5% 7% 6% 6% 8% 37%	4862

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	36% 11% 15% 23% 14% 1	2539
	11th to 20th	Day	39% 12% 12% 21% 12% 5%	2617
	21st to end	Day	46% 9% 11% 20% 12% 3	3146
February	1st to 10th	Day	35% 6% 13% 22% 16% 8%	1710
	11th to 20th	Day	35% 7% 13% 23% 17% 5%	1845
	21st to end	Day	36% 8% 14% 23% 16% 4	1570
March	1st to 10th	Day	49% 15% 11% 12% 10% 3	3138
	11th to 20th	Day	25% 9% 11% 32% 21% 3	3458
	21st to end	Day	36% 13% 18% 21% 10% 2	4058
April	1st to 10th	Day	34% 10% 15% 22% 15% 4	2270
	11th to 20th	Day	31% 8% 12% 25% 19% 5%	2132
	21st to end	Day	28% 6% 15% 27% 21% 3	2160
May	1st to 10th	Day	25% 5% 11% 31% 24% 4	2255
	11th to 20th	Day	28% 5% 12% 26% 24% 6%	2457
	21st to end	Day	35% 7% 12% 24% 19% 4	2724
June	1st to 10th	Day	25% 5% 10% 22% 30% 8%	2520
	11th to 20th	Day	13% 4 8% 23% 34% 18%	2520
	21st to end	Day	11% 3 5% 16% 35% 31%	2520
July	1st to 10th	Day	8% 2 4 11% 27% 48%	2451
	11th to 20th	Day	9% 2 4 13% 26% 46%	2445
	21st to end	Day	13% 3 6% 10% 23% 45%	2521
August	1st to 10th	Day	14% 3 5% 12% 24% 42%	2304
	11th to 20th	Day	10% 3 4 10% 31% 43%	2122
	21st to end	Day	7% 2 3 10% 36% 42%	2376
September	1st to 10th	Day	9% 2 3 11% 33% 43%	2160
	11th to 20th	Day	15% 4 6% 18% 34% 23%	2141
	21st to end	Day	15% 2 5% 23% 34% 21%	1980
October	1st to 10th	Day	22% 4 7% 18% 32% 17%	1814
	11th to 20th	Day	17% 4 9% 23% 29% 18%	1800
	21st to end	Day	19% 5% 10% 25% 25% 16%	1943
November	1st to 10th	Day	29% 6% 11% 21% 22% 11%	1674
	11th to 20th	Day	25% 10% 13% 22% 24% 6%	1710
	21st to end	Day	28% 7% 10% 25% 22% 8%	1630
December	1st to 10th	Day	34% 8% 13% 21% 18% 5%	1520
	11th to 20th	Day	47% 11% 8% 16% 12% 5%	1928
	21st to end	Day	35% 9% 17% 19% 18% 3	2794
January	1st to 10th	Night	31% 13% 19% 22% 14% 1	4406
	11th to 20th	Night	39% 12% 14% 16% 13% 5%	4331
	21st to end	Night	46% 10% 11% 19% 11% 4	4521
February	1st to 10th	Night	35% 8% 12% 21% 18% 7%	2470
	11th to 20th	Night	31% 9% 13% 23% 19% 5%	2233
	21st to end	Night	33% 10% 14% 21% 17% 5%	1884
March	1st to 10th	Night	44% 11% 11% 18% 13% 3	3736
	11th to 20th	Night	25% 10% 9% 33% 20% 3	3508
	21st to end	Night	40% 16% 17% 17% 8% 2	3594
April	1st to 10th	Night	32% 10% 16% 24% 14% 4	1900
	11th to 20th	Night	28% 7% 17% 25% 17% 5%	1779
	21st to end	Night	25% 7% 18% 30% 17% 3	1800
May	1st to 10th	Night	23% 8% 11% 28% 26% 4	1702
	11th to 20th	Night	25% 5% 15% 29% 20% 6%	1434
	21st to end	Night	27% 7% 15% 30% 17% 3	1552
June	1st to 10th	Night	23% 6% 10% 25% 28% 8%	1440
	11th to 20th	Night	11% 4 9% 24% 34% 18%	1440
	21st to end	Night	12% 3 6% 15% 34% 29%	1440
July	1st to 10th	Night	9% 2 4 8% 32% 45%	1400
	11th to 20th	Night	9% 3 4 12% 26% 47%	1392
	21st to end	Night	13% 3 5% 8% 25% 45%	1552
August	1st to 10th	Night	16% 4 4 14% 24% 37%	1609
	11th to 20th	Night	11% 3 4 12% 31% 40%	1780
	21st to end	Night	8% 2 3 12% 34% 40%	1980
September	1st to 10th	Night	7% 2 3 10% 35% 43%	1800
	11th to 20th	Night	11% 3 7% 21% 38% 21%	1818
	21st to end	Night	14% 3 6% 21% 35% 21%	1980
October	1st to 10th	Night	20% 4 8% 20% 30% 18%	2142
	11th to 20th	Night	15% 4 8% 22% 32% 18%	2160
	21st to end	Night	16% 5% 10% 25% 31% 13%	2412
November	1st to 10th	Night	26% 8% 12% 21% 22% 11%	2405
	11th to 20th	Night	23% 7% 13% 25% 25% 7%	2470
	21st to end	Night	29% 6% 10% 24% 21% 10%	2547
December	1st to 10th	Night	31% 10% 12% 19% 21% 7%	2660
	11th to 20th	Night	42% 12% 9% 16% 17% 5%	3276
	21st to end	Night	39% 13% 14% 15% 16% 3	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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	33% 22% 23% 13% 9% 1	180
	11th to 20th	Day	28% 19% 21% 21% 10% 1	231
	21st to end	Day	16% 24% 29% 20% 8% 3	407
February	1st to 10th	Day	22% 24% 27% 17% 8% 1	370
	11th to 20th	Day	24% 24% 27% 20% 5%	448
	21st to end	Day	24% 22% 33% 17% 4 1	382
March	1st to 10th	Day	30% 29% 25% 11% 4 1	460
	11th to 20th	Day	25% 25% 24% 16% 8% 1	460
	21st to end	Day	23% 31% 27% 15% 4	506
April	1st to 10th	Day	20% 28% 27% 16% 7% 1	457
	11th to 20th	Day	25% 28% 26% 14% 5% 1	412
	21st to end	Day	18% 25% 27% 19% 9% 2	420
May	1st to 10th	Day	19% 26% 26% 21% 6% 2	423
	11th to 20th	Day	19% 24% 26% 19% 8% 3	448
	21st to end	Day	18% 19% 25% 21% 13% 4	485
June	1st to 10th	Day	13% 20% 32% 21% 11% 4	450
	11th to 20th	Day	13% 21% 36% 18% 11% 2	450
	21st to end	Day	4 16% 35% 27% 15% 4	450
July	1st to 10th	Day	3 14% 42% 27% 13% 2	446
	11th to 20th	Day	2 11% 41% 30% 14% 3	444
	21st to end	Day	2 10% 36% 32% 16% 5%	487
August	1st to 10th	Day	4 13% 34% 30% 15% 4	447
	11th to 20th	Day	3 12% 35% 26% 19% 5%	437
	21st to end	Day	3 12% 42% 27% 14% 2	495
September	1st to 10th	Day	4 11% 38% 29% 16% 2	450
	11th to 20th	Day	8% 17% 29% 30% 15% 2	450
	21st to end	Day	8% 17% 36% 27% 11% 1	450
October	1st to 10th	Day	9% 21% 26% 26% 15% 2	450
	11th to 20th	Day	11% 17% 23% 30% 14% 4	450
	21st to end	Day	12% 20% 28% 22% 17% 2	458
November	1st to 10th	Day	20% 16% 22% 19% 20% 4	270
	11th to 20th	Day	12% 18% 26% 22% 16% 6%	270
	21st to end	Day	13% 22% 24% 23% 15% 3	232
December	1st to 10th	Day	24% 19% 21% 18% 14% 3	180
	11th to 20th	Day	20% 27% 21% 16% 11% 5%	180
	21st to end	Day	27% 21% 25% 17% 9% 2	198
January	1st to 10th	Night	15% 16% 24% 23% 14% 7%	760
	11th to 20th	Night	16% 13% 22% 33% 12% 4	760
	21st to end	Night	11% 15% 28% 25% 17% 4	836
February	1st to 10th	Night	15% 14% 26% 27% 14% 3	760
	11th to 20th	Night	14% 15% 25% 26% 14% 5%	744
	21st to end	Night	19% 14% 22% 32% 11% 2	628
March	1st to 10th	Night	19% 20% 25% 20% 13% 3	760
	11th to 20th	Night	14% 22% 20% 22% 19% 3	760
	21st to end	Night	15% 26% 23% 23% 11% 1	836
April	1st to 10th	Night	10% 21% 28% 26% 14% 1	760
	11th to 20th	Night	14% 20% 23% 25% 13% 4	711
	21st to end	Night	10% 17% 25% 26% 18% 4	720
May	1st to 10th	Night	12% 16% 26% 26% 17% 3	622
	11th to 20th	Night	9% 12% 22% 34% 20% 2	372
	21st to end	Night	11% 10% 18% 34% 25% 3	389
June	1st to 10th	Night	6% 11% 21% 36% 23% 3	360
	11th to 20th	Night	4 11% 23% 36% 26% 1	360
	21st to end	Night	3 6% 21% 41% 26% 3	360
July	1st to 10th	Night	2 3 20% 45% 28% 2	350
	11th to 20th	Night	2 5% 23% 39% 31%	348
	21st to end	Night	2 3 16% 39% 34% 6%	461
August	1st to 10th	Night	3 2 17% 40% 33% 4	544
	11th to 20th	Night	2 4 20% 41% 29% 4	712
	21st to end	Night	2 5% 26% 41% 24% 3	792
September	1st to 10th	Night	2 6% 21% 38% 30% 4	720
	11th to 20th	Night	4 10% 19% 29% 31% 7%	720
	21st to end	Night	5% 10% 21% 31% 23% 10%	720
October	1st to 10th	Night	8% 10% 19% 35% 22% 6%	720
	11th to 20th	Night	10% 6% 17% 37% 24% 6%	720
	21st to end	Night	10% 11% 17% 27% 24% 11%	792
November	1st to 10th	Night	14% 13% 17% 25% 24% 7%	740
	11th to 20th	Night	11% 15% 23% 29% 17% 5%	760
	21st to end	Night	12% 14% 21% 28% 19% 5%	760
December	1st to 10th	Night	17% 13% 21% 29% 15% 4	760
	11th to 20th	Night	17% 17% 24% 25% 12% 5%	760
	21st to end	Night	18% 18% 27% 24% 11% 2	836

Page generated at 2024-04-07 06:28:10. Version ac07

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