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 2026-08-30.

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	2 3 1 3 2 2 3 2 4 5% 72%	151715
	Night	3 4 1 4 3 3 3 3 4 6% 68%	148058
Transparency	Day	14% 4 7% 17% 30% 28%	146792
	Night	17% 5% 8% 18% 28% 24%	143957
Seeing	Day	5% 7% 20% 32% 26% 10%	17956
	Night	4 4 12% 36% 36% 8%	27568

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	3 7% 3 6% 4 4 5% 4 6% 7% 51%	4842
	11th to 20th	Day	3 3 1 3 2 4 3 3 5% 7% 67%	5340
	21st to end	Day	5% 6% 2 6% 4 4 5% 4 6% 8% 52%	5843
February	1st to 10th	Day	6% 6% 2 6% 3 3 3 3 5% 7% 54%	2065
	11th to 20th	Day	5% 6% 2 6% 4 4 4 4 7% 8% 50%	2050
	21st to end	Day	5% 6% 2 5% 4 5% 4 4 5% 8% 52%	1730
March	1st to 10th	Day	7% 7% 3 7% 5% 5% 5% 4 6% 8% 43%	4618
	11th to 20th	Day	3 5% 2 7% 5% 4 4 4 5% 7% 56%	5064
	21st to end	Day	3 4 2 6% 5% 6% 6% 5% 8% 9% 45%	5962
April	1st to 10th	Day	5% 4 2 4 4 3 4 4 6% 8% 56%	2520
	11th to 20th	Day	3 4 1 4 3 3 4 3 5% 7% 62%	2489
	21st to end	Day	3 3 1 2 4 3 4 3 5% 7% 66%	2520
May	1st to 10th	Day	2 2 1 2 2 2 2 2 3 5% 77%	7058
	11th to 20th	Day	1 1 1 1 1 2 2 3 5% 83%	7482
	21st to end	Day	2 1 1 1 2 2 2 3 5% 82%	8702
June	1st to 10th	Day	1 1 1 2 1 2 3 2 4 7% 75%	2940
	11th to 20th	Day	1 1 1 1 1 1 1 2 3 89%	2940
	21st to end	Day	1 1 1 1 1 1 2 3 90%	2940
July	1st to 10th	Day	1 1 1 1 1 2 93%	8219
	11th to 20th	Day	1 1 1 1 1 1 2 2 2 4 85%	7944
	21st to end	Day	1 1 1 1 2 3 90%	8288
August	1st to 10th	Day	1 1 1 2 1 3 4 86%	5466
	11th to 20th	Day	1 1 1 95%	5484
	21st to end	Day	1 1 1 1 1 1 1 2 3 90%	6093
September	1st to 10th	Day	1 1 1 1 1 1 1 1 2 4 87%	2400
	11th to 20th	Day	2 1 2 1 1 1 1 2 3 85%	2345
	21st to end	Day	1 1 2 2 1 1 2 2 4 84%	2200
October	1st to 10th	Day	1 1 1 2 1 1 2 2 4 5% 80%	3423
	11th to 20th	Day	1 2 1 2 2 2 3 2 3 5% 77%	3261
	21st to end	Day	3 3 1 3 2 3 4 3 4 7% 67%	3558
November	1st to 10th	Day	3 4 2 3 3 3 3 2 4 6% 66%	1909
	11th to 20th	Day	4 4 1 4 4 3 4 4 5% 6% 60%	1890
	21st to end	Day	5% 5% 2 5% 4 5% 4 3 6% 6% 56%	1890
December	1st to 10th	Day	3 4 2 5% 4 4 5% 3 5% 7% 58%	3040
	11th to 20th	Day	6% 6% 2 6% 4 4 5% 5% 7% 8% 47%	3108
	21st to end	Day	6% 8% 3 7% 5% 5% 5% 4 7% 10% 39%	4092
January	1st to 10th	Night	5% 11% 3 7% 4 4 4 3 5% 6% 48%	8041
	11th to 20th	Night	3 3 2 4 3 3 3 3 5% 7% 64%	7650
	21st to end	Night	6% 8% 2 7% 5% 4 4 4 5% 7% 48%	8371
February	1st to 10th	Night	6% 7% 2 6% 4 3 3 3 5% 6% 55%	2552
	11th to 20th	Night	5% 5% 2 5% 4 3 3 5% 7% 8% 53%	2458
	21st to end	Night	4 4 2 5% 4 4 5% 3 6% 7% 55%	2076
March	1st to 10th	Night	5% 6% 3 7% 5% 5% 6% 4 7% 9% 44%	5496
	11th to 20th	Night	3 5% 2 6% 4 4 4 4 6% 7% 55%	5140
	21st to end	Night	6% 6% 2 6% 5% 4 4 4 6% 8% 48%	5253
April	1st to 10th	Night	4 4 2 4 3 3 4 4 5% 8% 60%	2100
	11th to 20th	Night	3 3 1 3 3 3 3 2 4 6% 68%	2079
	21st to end	Night	2 2 1 2 2 3 3 3 5% 7% 70%	2100
May	1st to 10th	Night	1 2 1 2 1 2 2 2 3 5% 79%	5919
	11th to 20th	Night	1 1 1 1 1 1 1 3 5% 85%	5414
	21st to end	Night	1 1 1 1 1 1 1 2 3 88%	5481
June	1st to 10th	Night	1 1 2 1 2 2 1 3 5% 82%	1680
	11th to 20th	Night	1 1 1 1 3 3 90%	1680
	21st to end	Night	1 1 1 1 2 92%	1680
July	1st to 10th	Night	1 1 1 3 93%	4740
	11th to 20th	Night	1 1 1 1 1 1 1 2 3 88%	5013
	21st to end	Night	1 1 1 1 1 2 3 90%	5820
August	1st to 10th	Night	1 1 1 1 2 3 90%	4586
	11th to 20th	Night	1 1 1 1 2 94%	4606
	21st to end	Night	1 1 1 1 1 2 3 90%	5105
September	1st to 10th	Night	1 1 1 1 1 2 1 2 3 87%	2000
	11th to 20th	Night	1 2 1 2 1 1 2 2 2 4 83%	2053
	21st to end	Night	1 1 1 1 1 1 2 2 3 4 84%	2200
October	1st to 10th	Night	1 1 1 1 1 1 1 1 3 4 84%	3760
	11th to 20th	Night	1 1 1 2 2 2 2 3 3 4 79%	3897
	21st to end	Night	2 3 1 4 2 2 2 2 3 5% 73%	4253
November	1st to 10th	Night	2 4 1 4 3 3 3 2 4 7% 66%	2608
	11th to 20th	Night	3 4 1 4 4 3 3 4 5% 7% 62%	2730
	21st to end	Night	5% 5% 2 5% 4 3 5% 4 6% 7% 53%	2730
December	1st to 10th	Night	3 3 2 4 3 4 3 4 6% 7% 61%	4370
	11th to 20th	Night	6% 7% 2 7% 5% 5% 6% 5% 8% 9% 41%	5311
	21st to end	Night	6% 10% 3 7% 6% 6% 7% 6% 7% 9% 33%	7106

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	26% 7% 12% 25% 18% 11%	4843
	11th to 20th	Day	16% 5% 9% 12% 21% 37%	5340
	21st to end	Day	27% 6% 9% 14% 26% 18%	5843
February	1st to 10th	Day	29% 4 8% 19% 24% 16%	2065
	11th to 20th	Day	28% 6% 11% 22% 23% 10%	2060
	21st to end	Day	27% 8% 11% 23% 25% 7%	1730
March	1st to 10th	Day	32% 8% 13% 14% 22% 10%	4618
	11th to 20th	Day	23% 7% 13% 30% 18% 8%	5064
	21st to end	Day	25% 11% 16% 27% 18% 3	5962
April	1st to 10th	Day	24% 5% 12% 25% 25% 8%	2520
	11th to 20th	Day	20% 5% 12% 27% 27% 9%	2492
	21st to end	Day	17% 6% 12% 27% 32% 7%	2520
May	1st to 10th	Day	11% 4 8% 21% 41% 16%	7058
	11th to 20th	Day	6% 2 5% 19% 45% 24%	7485
	21st to end	Day	8% 2 5% 23% 49% 12%	8703
June	1st to 10th	Day	9% 5% 9% 20% 37% 20%	2940
	11th to 20th	Day	4 1 5% 14% 37% 38%	2940
	21st to end	Day	4 1 3 7% 35% 51%	2940
July	1st to 10th	Day	3 1 4 22% 70%	8151
	11th to 20th	Day	7% 1 4 9% 25% 54%	7869
	21st to end	Day	3 1 2 15% 34% 45%	8103
August	1st to 10th	Day	5% 1 3 9% 37% 44%	4010
	11th to 20th	Day	2 1 8% 32% 56%	4000
	21st to end	Day	4 1 2 10% 34% 49%	4420
September	1st to 10th	Day	5% 2 4 9% 34% 47%	2400
	11th to 20th	Day	7% 1 4 16% 43% 29%	2345
	21st to end	Day	7% 1 4 16% 41% 31%	2200
October	1st to 10th	Day	8% 2 5% 13% 22% 50%	3423
	11th to 20th	Day	12% 2 5% 19% 40% 22%	3261
	21st to end	Day	18% 3 5% 11% 34% 28%	3558
November	1st to 10th	Day	19% 5% 7% 19% 29% 21%	1909
	11th to 20th	Day	21% 4 10% 19% 26% 19%	1890
	21st to end	Day	27% 5% 8% 16% 23% 22%	1890
December	1st to 10th	Day	24% 4 7% 12% 29% 24%	3040
	11th to 20th	Day	29% 8% 13% 16% 21% 13%	3108
	21st to end	Day	35% 9% 14% 20% 18% 5%	4092
January	1st to 10th	Night	33% 8% 12% 23% 16% 9%	8041
	11th to 20th	Night	17% 7% 7% 12% 25% 32%	7650
	21st to end	Night	31% 7% 8% 14% 26% 15%	8371
February	1st to 10th	Night	28% 5% 9% 18% 24% 15%	2552
	11th to 20th	Night	25% 7% 10% 25% 24% 10%	2459
	21st to end	Night	26% 7% 12% 23% 26% 6%	2076
March	1st to 10th	Night	28% 10% 15% 20% 22% 6%	5496
	11th to 20th	Night	23% 9% 14% 32% 16% 7%	5140
	21st to end	Night	27% 12% 16% 26% 16% 2	5253
April	1st to 10th	Night	20% 8% 15% 28% 22% 7%	2100
	11th to 20th	Night	18% 5% 13% 26% 30% 8%	2079
	21st to end	Night	12% 5% 15% 32% 30% 7%	2100
May	1st to 10th	Night	9% 3 10% 24% 39% 14%	5917
	11th to 20th	Night	5% 2 4 23% 45% 22%	5415
	21st to end	Night	5% 1 6% 26% 51% 12%	5482
June	1st to 10th	Night	7% 3 9% 22% 39% 20%	1680
	11th to 20th	Night	3 1 5% 15% 37% 39%	1680
	21st to end	Night	3 1 2 6% 36% 51%	1680
July	1st to 10th	Night	2 1 1 5% 23% 69%	4700
	11th to 20th	Night	6% 1 3 9% 23% 58%	4965
	21st to end	Night	3 1 2 16% 33% 45%	5693
August	1st to 10th	Night	5% 1 2 10% 35% 46%	3356
	11th to 20th	Night	3 1 2 8% 29% 58%	3356
	21st to end	Night	3 1 2 9% 33% 52%	3698
September	1st to 10th	Night	6% 2 3 10% 31% 49%	2000
	11th to 20th	Night	7% 2 3 13% 45% 30%	2053
	21st to end	Night	6% 2 5% 16% 40% 31%	2200
October	1st to 10th	Night	7% 2 4 11% 25% 51%	3760
	11th to 20th	Night	10% 2 5% 21% 41% 21%	3897
	21st to end	Night	15% 2 5% 15% 36% 27%	4253
November	1st to 10th	Night	17% 5% 8% 22% 27% 21%	2608
	11th to 20th	Night	21% 5% 11% 18% 26% 19%	2730
	21st to end	Night	25% 6% 10% 18% 23% 18%	2730
December	1st to 10th	Night	20% 4 7% 16% 34% 19%	4370
	11th to 20th	Night	33% 10% 13% 15% 17% 13%	5311
	21st to end	Night	40% 9% 16% 18% 14% 4	7106

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% 29% 33% 10% 2	262
	11th to 20th	Day	9% 11% 29% 33% 13% 4	430
	21st to end	Day	10% 13% 28% 31% 15% 3	473
February	1st to 10th	Day	10% 13% 29% 28% 14% 6%	523
	11th to 20th	Day	12% 15% 28% 30% 12% 2	535
	21st to end	Day	10% 12% 31% 32% 14% 2	446
March	1st to 10th	Day	14% 17% 29% 28% 11% 1	540
	11th to 20th	Day	9% 14% 28% 32% 14% 3	540
	21st to end	Day	8% 16% 32% 30% 10% 3	594
April	1st to 10th	Day	9% 12% 29% 28% 19% 4	540
	11th to 20th	Day	6% 14% 29% 30% 18% 3	532
	21st to end	Day	5% 11% 28% 30% 19% 6%	540
May	1st to 10th	Day	7% 8% 29% 30% 19% 6%	543
	11th to 20th	Day	4 10% 22% 35% 23% 7%	568
	21st to end	Day	4 9% 20% 36% 23% 7%	617
June	1st to 10th	Day	2 6% 18% 33% 31% 11%	570
	11th to 20th	Day	1 4 19% 38% 29% 9%	570
	21st to end	Day	3 13% 35% 34% 16%	570
July	1st to 10th	Day	1 7% 32% 41% 18%	566
	11th to 20th	Day	1 1 5% 28% 37% 29%	564
	21st to end	Day	1 1 4 28% 41% 25%	619
August	1st to 10th	Day	2 1 8% 33% 36% 21%	567
	11th to 20th	Day	1 6% 31% 42% 19%	557
	21st to end	Day	1 1 5% 33% 39% 20%	620
September	1st to 10th	Day	1 1 11% 30% 42% 15%	530
	11th to 20th	Day	3 2 15% 39% 33% 8%	530
	21st to end	Day	1 3 18% 34% 35% 9%	530
October	1st to 10th	Day	1 5% 18% 35% 33% 8%	530
	11th to 20th	Day	2 5% 21% 35% 29% 8%	530
	21st to end	Day	3 5% 21% 33% 29% 9%	583
November	1st to 10th	Day	5% 7% 19% 34% 28% 8%	385
	11th to 20th	Day	7% 8% 21% 33% 25% 5%	330
	21st to end	Day	7% 9% 20% 36% 25% 4	330
December	1st to 10th	Day	5% 5% 23% 40% 23% 4	330
	11th to 20th	Day	7% 12% 16% 32% 23% 10%	220
	21st to end	Day	16% 12% 29% 29% 11% 5%	242
January	1st to 10th	Night	11% 6% 16% 38% 19% 10%	840
	11th to 20th	Night	6% 4 15% 44% 24% 7%	840
	21st to end	Night	10% 5% 15% 43% 21% 5%	924
February	1st to 10th	Night	8% 7% 16% 40% 22% 7%	840
	11th to 20th	Night	7% 6% 19% 40% 20% 7%	824
	21st to end	Night	7% 8% 18% 45% 19% 4	692
March	1st to 10th	Night	7% 7% 20% 42% 21% 3	840
	11th to 20th	Night	7% 6% 15% 39% 27% 6%	840
	21st to end	Night	6% 8% 18% 39% 26% 3	924
April	1st to 10th	Night	5% 6% 17% 44% 24% 3	840
	11th to 20th	Night	5% 5% 16% 42% 28% 4	831
	21st to end	Night	3 5% 18% 38% 30% 6%	840
May	1st to 10th	Night	2 4 13% 42% 33% 5%	840
	11th to 20th	Night	2 3 14% 37% 38% 5%	663
	21st to end	Night	1 5% 14% 42% 35% 4	561
June	1st to 10th	Night	1 1 8% 36% 50% 4	420
	11th to 20th	Night	7% 37% 52% 4	420
	21st to end	Night	1 6% 31% 54% 9%	420
July	1st to 10th	Night	1 20% 70% 8%	410
	11th to 20th	Night	1 16% 64% 18%	499
	21st to end	Night	1 1 1 15% 63% 19%	692
August	1st to 10th	Night	1 2 23% 61% 13%	836
	11th to 20th	Night	2 21% 63% 14%	832
	21st to end	Night	1 1 21% 62% 14%	916
September	1st to 10th	Night	1 1 3 24% 58% 13%	800
	11th to 20th	Night	2 1 6% 32% 48% 12%	800
	21st to end	Night	1 1 7% 33% 51% 8%	800
October	1st to 10th	Night	2 1 9% 39% 43% 7%	800
	11th to 20th	Night	3 3 9% 39% 38% 10%	800
	21st to end	Night	3 1 9% 40% 37% 9%	880
November	1st to 10th	Night	4 3 12% 39% 32% 10%	820
	11th to 20th	Night	5% 3 13% 43% 29% 8%	840
	21st to end	Night	6% 4 15% 41% 25% 9%	840
December	1st to 10th	Night	6% 4 16% 40% 28% 6%	840
	11th to 20th	Night	9% 4 14% 46% 21% 5%	840
	21st to end	Night	9% 8% 19% 39% 18% 6%	924

Page generated at 2026-08-27 01:07:14. Version ac07

Copyright © 2026 Attilla Danko.