Carrizo Plain National Monument
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carrizo Plain National Monument clear sky chart from 2005-11-06 to 2024-10-25.

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 3 1 3 3 3 3 3 4 6% 70%	100719
	Night	3 4 1 4 3 3 3 3 4 6% 66%	98324
Transparency	Day	15% 5% 8% 17% 28% 28%	100473
	Night	18% 6% 9% 19% 25% 24%	98160
Seeing	Day	5% 7% 20% 32% 27% 9%	15501
	Night	4 4 11% 36% 37% 8%	25139

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	4 7% 3 5% 4 4 5% 4 6% 8% 50%	2603
	11th to 20th	Day	5% 5% 2 5% 4 6% 5% 4 7% 9% 47%	2860
	21st to end	Day	7% 9% 3 8% 5% 5% 5% 5% 7% 9% 38%	3146
February	1st to 10th	Day	7% 7% 2 6% 3 3 3 3 5% 7% 54%	1867
	11th to 20th	Day	4 6% 2 6% 4 4 4 4 6% 8% 52%	1850
	21st to end	Day	5% 6% 2 6% 4 4 4 4 4 8% 51%	1570
March	1st to 10th	Day	5% 7% 3 7% 6% 6% 6% 5% 7% 9% 39%	3138
	11th to 20th	Day	3 5% 1 4 3 3 4 3 5% 7% 61%	3458
	21st to end	Day	4 5% 2 7% 6% 7% 7% 5% 8% 9% 41%	4068
April	1st to 10th	Day	6% 5% 1 4 4 4 4 4 6% 8% 55%	2280
	11th to 20th	Day	3 4 1 4 3 3 4 3 6% 7% 63%	2249
	21st to end	Day	3 3 1 2 3 2 4 3 5% 7% 68%	2280
May	1st to 10th	Day	2 2 1 2 1 2 2 2 3 5% 79%	3800
	11th to 20th	Day	2 1 1 1 1 2 2 3 5% 81%	4008
	21st to end	Day	2 1 1 1 2 2 2 3 4 83%	4653
June	1st to 10th	Day	2 1 1 2 2 2 3 3 4 7% 74%	2660
	11th to 20th	Day	1 1 1 1 1 1 1 2 3 88%	2660
	21st to end	Day	1 1 1 1 1 1 2 3 89%	2660
July	1st to 10th	Day	1 2 2 92%	4420
	11th to 20th	Day	1 1 1 2 1 1 2 2 2 4 83%	4274
	21st to end	Day	1 1 1 1 1 1 1 2 3 87%	4439
August	1st to 10th	Day	1 1 1 1 1 1 2 4 87%	3783
	11th to 20th	Day	1 1 1 1 1 94%	3724
	21st to end	Day	1 1 1 1 1 1 2 92%	4180
September	1st to 10th	Day	1 1 1 1 1 1 1 1 2 4 87%	2280
	11th to 20th	Day	1 1 2 1 1 1 1 2 3 86%	2228
	21st to end	Day	1 1 1 1 1 1 2 2 4 85%	2090
October	1st to 10th	Day	2 2 1 2 2 2 3 3 4 5% 73%	1990
	11th to 20th	Day	1 3 1 3 2 3 3 2 4 5% 74%	1900
	21st to end	Day	1 2 1 2 2 2 3 3 5% 7% 73%	2025
November	1st to 10th	Day	3 4 2 4 3 4 3 3 5% 6% 64%	1724
	11th to 20th	Day	3 4 1 4 3 3 4 5% 5% 6% 62%	1710
	21st to end	Day	5% 4 2 5% 4 5% 4 4 6% 6% 56%	1710
December	1st to 10th	Day	6% 5% 2 6% 4 4 5% 4 5% 8% 51%	1710
	11th to 20th	Day	9% 8% 3 7% 5% 4 5% 4 8% 9% 38%	1928
	21st to end	Day	7% 9% 3 8% 6% 6% 5% 4 6% 7% 39%	2794
January	1st to 10th	Night	5% 11% 3 7% 5% 5% 4 3 5% 7% 46%	4340
	11th to 20th	Night	6% 6% 3 8% 5% 5% 5% 4 6% 8% 43%	4110
	21st to end	Night	8% 9% 3 8% 5% 4 5% 4 6% 8% 38%	4521
February	1st to 10th	Night	6% 7% 2 6% 4 3 3 3 5% 6% 55%	2310
	11th to 20th	Night	5% 5% 2 4 4 3 3 5% 6% 8% 56%	2218
	21st to end	Night	4 4 2 6% 4 4 5% 3 6% 7% 55%	1884
March	1st to 10th	Night	5% 6% 2 5% 5% 5% 6% 5% 7% 10% 42%	3736
	11th to 20th	Night	3 5% 1 4 3 4 4 4 6% 8% 58%	3506
	21st to end	Night	7% 6% 2 5% 5% 5% 5% 4 7% 8% 46%	3583
April	1st to 10th	Night	4 4 2 4 3 4 4 4 6% 8% 59%	1900
	11th to 20th	Night	3 3 1 3 3 3 2 2 4 5% 70%	1879
	21st to end	Night	2 2 1 2 1 3 3 3 5% 8% 71%	1900
May	1st to 10th	Night	1 1 1 2 1 1 2 1 3 5% 82%	3180
	11th to 20th	Night	1 1 1 1 1 2 2 5% 6% 81%	2898
	21st to end	Night	1 1 1 1 1 1 1 3 3 87%	2922
June	1st to 10th	Night	1 1 2 2 2 3 2 3 5% 80%	1520
	11th to 20th	Night	1 1 1 1 3 3 89%	1520
	21st to end	Night	1 1 1 1 2 2 92%	1520
July	1st to 10th	Night	1 1 2 3 92%	2540
	11th to 20th	Night	1 1 1 1 1 2 2 3 88%	2687
	21st to end	Night	1 1 1 1 1 1 1 2 3 89%	3123
August	1st to 10th	Night	1 1 1 1 1 1 1 2 2 89%	3166
	11th to 20th	Night	1 1 1 1 2 93%	3126
	21st to end	Night	1 1 1 1 2 94%	3498
September	1st to 10th	Night	1 1 1 1 1 2 1 2 3 87%	1900
	11th to 20th	Night	1 1 2 1 1 2 2 2 4 84%	1950
	21st to end	Night	1 1 1 1 1 2 2 3 4 85%	2090
October	1st to 10th	Night	2 2 1 2 2 2 2 2 3 5% 77%	2185
	11th to 20th	Night	2 2 1 3 3 2 3 3 4 5% 73%	2280
	21st to end	Night	2 2 1 3 2 2 2 2 4 5% 76%	2436
November	1st to 10th	Night	3 4 1 4 3 3 3 3 4 8% 64%	2353
	11th to 20th	Night	2 4 1 4 3 3 3 4 5% 7% 63%	2470
	21st to end	Night	4 4 2 5% 4 3 5% 4 6% 7% 54%	2470
December	1st to 10th	Night	5% 5% 2 6% 4 4 4 4 6% 8% 53%	2470
	11th to 20th	Night	8% 9% 3 8% 4 5% 5% 4 7% 9% 38%	3271
	21st to end	Night	8% 9% 2 8% 6% 6% 6% 5% 6% 7% 38%	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	24% 10% 15% 31% 15% 5%	2603
	11th to 20th	Day	28% 10% 15% 23% 15% 10%	2860
	21st to end	Day	35% 11% 14% 17% 15% 9%	3146
February	1st to 10th	Day	29% 4 8% 19% 23% 16%	1867
	11th to 20th	Day	27% 6% 10% 22% 25% 11%	1860
	21st to end	Day	28% 8% 11% 23% 24% 6%	1570
March	1st to 10th	Day	32% 11% 15% 18% 18% 6%	3138
	11th to 20th	Day	18% 8% 16% 29% 19% 10%	3458
	21st to end	Day	27% 14% 16% 25% 14% 4	4068
April	1st to 10th	Day	25% 6% 13% 25% 23% 9%	2280
	11th to 20th	Day	19% 5% 13% 27% 26% 10%	2252
	21st to end	Day	15% 6% 12% 27% 33% 7%	2280
May	1st to 10th	Day	10% 4 8% 22% 34% 22%	3800
	11th to 20th	Day	7% 2 6% 20% 37% 28%	4011
	21st to end	Day	8% 2 6% 24% 47% 13%	4653
June	1st to 10th	Day	9% 5% 9% 21% 35% 20%	2660
	11th to 20th	Day	4 1 6% 15% 38% 35%	2660
	21st to end	Day	4 1 3 7% 34% 51%	2660
July	1st to 10th	Day	2 1 2 4 17% 74%	4351
	11th to 20th	Day	8% 1 4 6% 20% 61%	4199
	21st to end	Day	5% 2 3 14% 29% 47%	4299
August	1st to 10th	Day	5% 1 3 9% 36% 46%	3770
	11th to 20th	Day	2 1 7% 32% 58%	3760
	21st to end	Day	3 1 2 9% 34% 51%	4179
September	1st to 10th	Day	5% 2 4 9% 32% 48%	2280
	11th to 20th	Day	6% 1 4 17% 43% 30%	2228
	21st to end	Day	6% 1 4 15% 42% 32%	2090
October	1st to 10th	Day	12% 4 7% 20% 25% 33%	1990
	11th to 20th	Day	14% 3 5% 15% 34% 29%	1900
	21st to end	Day	11% 4 7% 16% 31% 31%	2025
November	1st to 10th	Day	20% 5% 8% 19% 29% 20%	1724
	11th to 20th	Day	20% 4 10% 19% 27% 21%	1710
	21st to end	Day	26% 5% 8% 16% 24% 21%	1710
December	1st to 10th	Day	29% 6% 9% 17% 20% 18%	1710
	11th to 20th	Day	35% 11% 13% 16% 15% 10%	1928
	21st to end	Day	37% 10% 12% 19% 18% 6%	2794
January	1st to 10th	Night	32% 10% 10% 25% 18% 5%	4340
	11th to 20th	Night	29% 13% 13% 21% 15% 9%	4110
	21st to end	Night	36% 11% 12% 19% 13% 9%	4521
February	1st to 10th	Night	29% 6% 9% 18% 24% 15%	2310
	11th to 20th	Night	23% 7% 10% 25% 25% 11%	2219
	21st to end	Night	27% 7% 12% 23% 27% 5%	1884
March	1st to 10th	Night	27% 14% 16% 23% 16% 4	3736
	11th to 20th	Night	19% 11% 13% 32% 16% 9%	3506
	21st to end	Night	27% 16% 15% 24% 16% 3	3583
April	1st to 10th	Night	21% 8% 15% 28% 21% 7%	1900
	11th to 20th	Night	18% 5% 13% 26% 29% 9%	1879
	21st to end	Night	11% 5% 15% 32% 30% 7%	1900
May	1st to 10th	Night	7% 4 8% 27% 32% 23%	3180
	11th to 20th	Night	6% 3 6% 23% 38% 24%	2899
	21st to end	Night	5% 2 9% 26% 44% 14%	2922
June	1st to 10th	Night	8% 4 10% 22% 36% 21%	1520
	11th to 20th	Night	3 2 6% 16% 39% 35%	1520
	21st to end	Night	3 1 3 7% 35% 52%	1520
July	1st to 10th	Night	2 1 2 5% 17% 73%	2500
	11th to 20th	Night	3 1 3 9% 17% 67%	2639
	21st to end	Night	4 2 3 13% 30% 49%	3025
August	1st to 10th	Night	6% 1 2 10% 34% 47%	3156
	11th to 20th	Night	2 1 1 6% 28% 61%	3156
	21st to end	Night	3 1 2 8% 33% 54%	3498
September	1st to 10th	Night	6% 2 3 10% 29% 51%	1900
	11th to 20th	Night	6% 2 3 14% 45% 31%	1950
	21st to end	Night	5% 2 4 17% 41% 31%	2090
October	1st to 10th	Night	12% 4 7% 16% 29% 33%	2185
	11th to 20th	Night	14% 4 7% 18% 32% 25%	2280
	21st to end	Night	12% 3 6% 17% 33% 29%	2436
November	1st to 10th	Night	18% 6% 9% 22% 27% 20%	2353
	11th to 20th	Night	19% 5% 11% 18% 26% 21%	2470
	21st to end	Night	24% 6% 10% 18% 23% 18%	2470
December	1st to 10th	Night	27% 7% 10% 19% 19% 18%	2470
	11th to 20th	Night	36% 11% 12% 17% 16% 9%	3271
	21st to end	Night	37% 9% 13% 21% 15% 5%	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	14% 12% 27% 33% 11% 2	218
	11th to 20th	Day	10% 11% 28% 34% 14% 4	370
	21st to end	Day	11% 12% 29% 29% 16% 3	407
February	1st to 10th	Day	9% 13% 28% 28% 15% 6%	445
	11th to 20th	Day	9% 14% 27% 32% 15% 3	455
	21st to end	Day	10% 14% 29% 31% 14% 2	382
March	1st to 10th	Day	13% 16% 28% 30% 12% 1	460
	11th to 20th	Day	8% 15% 29% 32% 14% 2	460
	21st to end	Day	9% 17% 32% 30% 10% 3	506
April	1st to 10th	Day	9% 13% 29% 27% 20% 3	460
	11th to 20th	Day	7% 14% 29% 30% 17% 3	452
	21st to end	Day	5% 10% 28% 30% 20% 7%	460
May	1st to 10th	Day	7% 9% 31% 29% 19% 6%	463
	11th to 20th	Day	3 8% 23% 35% 23% 7%	488
	21st to end	Day	4 10% 21% 35% 24% 7%	529
June	1st to 10th	Day	2 6% 18% 33% 30% 11%	490
	11th to 20th	Day	1 4 18% 39% 30% 9%	490
	21st to end	Day	1 12% 35% 36% 16%	490
July	1st to 10th	Day	1 6% 33% 41% 19%	486
	11th to 20th	Day	1 4 29% 38% 27%	484
	21st to end	Day	1 1 4 27% 40% 27%	531
August	1st to 10th	Day	2 1 9% 34% 36% 18%	487
	11th to 20th	Day	2 5% 31% 43% 18%	477
	21st to end	Day	1 1 5% 32% 42% 20%	539
September	1st to 10th	Day	1 11% 30% 42% 15%	490
	11th to 20th	Day	2 2 15% 40% 33% 7%	490
	21st to end	Day	1 2 16% 34% 37% 10%	490
October	1st to 10th	Day	1 4 17% 35% 33% 9%	490
	11th to 20th	Day	2 5% 20% 35% 30% 8%	490
	21st to end	Day	2 5% 20% 33% 30% 10%	514
November	1st to 10th	Day	5% 7% 19% 33% 27% 8%	320
	11th to 20th	Day	4 7% 18% 35% 29% 6%	270
	21st to end	Day	6% 10% 18% 35% 27% 4	270
December	1st to 10th	Day	6% 6% 26% 38% 23% 2	270
	11th to 20th	Day	7% 14% 16% 32% 21% 10%	180
	21st to end	Day	14% 12% 28% 29% 12% 6%	198
January	1st to 10th	Night	11% 6% 14% 36% 21% 11%	760
	11th to 20th	Night	6% 4 14% 43% 25% 8%	760
	21st to end	Night	10% 6% 15% 42% 21% 6%	836
February	1st to 10th	Night	8% 7% 16% 39% 23% 7%	760
	11th to 20th	Night	6% 6% 17% 41% 22% 8%	744
	21st to end	Night	7% 8% 18% 43% 20% 4	628
March	1st to 10th	Night	8% 7% 18% 42% 22% 3	760
	11th to 20th	Night	6% 6% 15% 39% 28% 6%	760
	21st to end	Night	6% 8% 18% 39% 25% 3	836
April	1st to 10th	Night	5% 6% 17% 44% 25% 4	760
	11th to 20th	Night	5% 5% 17% 40% 29% 4	751
	21st to end	Night	3 5% 17% 38% 31% 6%	760
May	1st to 10th	Night	2 4 13% 43% 32% 6%	760
	11th to 20th	Night	3 3 13% 38% 39% 5%	599
	21st to end	Night	1 5% 15% 41% 35% 4	507
June	1st to 10th	Night	1 1 8% 35% 50% 4	380
	11th to 20th	Night	7% 37% 52% 4	380
	21st to end	Night	1 4 31% 56% 8%	380
July	1st to 10th	Night	1 16% 74% 9%	370
	11th to 20th	Night	16% 65% 18%	450
	21st to end	Night	1 1 1 13% 64% 21%	626
August	1st to 10th	Night	1 3 23% 60% 13%	756
	11th to 20th	Night	1 20% 63% 15%	752
	21st to end	Night	1 1 20% 63% 15%	836
September	1st to 10th	Night	1 1 2 23% 59% 14%	760
	11th to 20th	Night	1 1 6% 32% 48% 12%	760
	21st to end	Night	1 1 6% 32% 52% 9%	760
October	1st to 10th	Night	1 1 8% 38% 44% 7%	760
	11th to 20th	Night	3 2 8% 39% 39% 10%	760
	21st to end	Night	3 1 10% 39% 38% 10%	812
November	1st to 10th	Night	4 3 12% 38% 32% 11%	740
	11th to 20th	Night	4 1 12% 43% 31% 9%	760
	21st to end	Night	6% 4 15% 40% 26% 9%	760
December	1st to 10th	Night	7% 4 14% 41% 28% 6%	760
	11th to 20th	Night	10% 4 15% 44% 21% 5%	760
	21st to end	Night	8% 8% 18% 39% 20% 7%	836

Page generated at 2024-10-22 17:21:02. Version ac07

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