Pocatello
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pocatello clear sky chart from 2005-11-06 to 2026-01-17.

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	6% 9% 3 6% 4 4 4 3 5% 6% 51%	135877
	Night	7% 10% 3 7% 4 4 4 3 5% 6% 47%	133184
Transparency	Day	34% 5% 10% 21% 19% 12%	130587
	Night	37% 5% 11% 20% 17% 10%	129476
Seeing	Day	13% 13% 27% 28% 16% 4	16679
	Night	14% 7% 23% 36% 17% 2	26448

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	9% 25% 7% 10% 5% 4 4 2 4 5% 24%	3719
	11th to 20th	Day	7% 18% 7% 16% 7% 4 4 2 3 4 30%	3808
	21st to end	Day	8% 15% 4 10% 4 4 3 3 4 5% 40%	4510
February	1st to 10th	Day	12% 17% 6% 12% 7% 5% 4 4 5% 5% 25%	1800
	11th to 20th	Day	11% 19% 5% 11% 5% 3 4 3 6% 5% 28%	1810
	21st to end	Day	8% 17% 6% 10% 5% 5% 5% 3 5% 6% 30%	1650
March	1st to 10th	Day	7% 18% 6% 10% 5% 4 4 3 4 5% 34%	4727
	11th to 20th	Day	6% 13% 5% 7% 4 4 4 3 5% 5% 43%	5000
	21st to end	Day	8% 16% 5% 12% 7% 5% 5% 4 6% 6% 25%	5486
April	1st to 10th	Day	11% 11% 4 9% 5% 4 5% 5% 5% 6% 35%	2261
	11th to 20th	Day	8% 11% 4 7% 5% 4 4 4 5% 7% 41%	2567
	21st to end	Day	9% 11% 3 7% 5% 4 4 4 6% 8% 39%	2600
May	1st to 10th	Day	7% 10% 3 5% 3 4 4 3 4 7% 49%	5880
	11th to 20th	Day	8% 7% 3 6% 4 4 5% 4 6% 7% 46%	5841
	21st to end	Day	6% 6% 2 5% 3 3 4 3 5% 7% 56%	6607
June	1st to 10th	Day	7% 6% 2 4 4 4 4 5% 6% 8% 51%	2918
	11th to 20th	Day	7% 5% 2 5% 4 3 5% 4 5% 7% 54%	3000
	21st to end	Day	3 2 1 3 2 3 3 3 4 7% 70%	3000
July	1st to 10th	Day	1 1 1 2 2 2 3 3 4 5% 75%	6423
	11th to 20th	Day	1 1 1 3 3 3 3 3 5% 6% 71%	6276
	21st to end	Day	2 2 1 3 3 3 3 3 5% 7% 68%	6401
August	1st to 10th	Day	2 3 1 4 3 3 3 3 5% 8% 63%	5779
	11th to 20th	Day	2 2 1 3 2 3 4 3 5% 7% 69%	5798
	21st to end	Day	4 3 1 4 3 2 3 3 5% 6% 67%	6468
September	1st to 10th	Day	4 2 1 3 2 3 4 3 4 5% 68%	2289
	11th to 20th	Day	4 3 1 4 3 3 3 3 5% 7% 63%	2200
	21st to end	Day	7% 3 1 4 3 3 3 3 3 6% 64%	2200
October	1st to 10th	Day	7% 4 1 3 2 3 3 3 4 4 66%	3450
	11th to 20th	Day	6% 6% 2 5% 3 3 3 3 4 6% 59%	3250
	21st to end	Day	7% 9% 2 6% 4 4 4 4 6% 7% 46%	3369
November	1st to 10th	Day	12% 12% 3 6% 5% 3 4 3 5% 6% 41%	1854
	11th to 20th	Day	11% 12% 4 6% 4 3 4 3 7% 7% 39%	1839
	21st to end	Day	9% 12% 4 8% 5% 4 5% 3 5% 5% 40%	1680
December	1st to 10th	Day	8% 10% 3 8% 3 3 3 3 3 6% 51%	2700
	11th to 20th	Day	11% 17% 5% 12% 7% 5% 5% 4 6% 6% 23%	3030
	21st to end	Day	12% 16% 6% 12% 4 5% 5% 4 5% 7% 25%	3687
January	1st to 10th	Night	9% 18% 7% 13% 5% 5% 4 3 4 6% 26%	6446
	11th to 20th	Night	9% 18% 7% 15% 5% 3 3 3 4 5% 28%	6273
	21st to end	Night	7% 15% 4 8% 4 4 3 3 4 5% 44%	6468
February	1st to 10th	Night	12% 15% 5% 12% 5% 4 5% 3 6% 6% 28%	2600
	11th to 20th	Night	10% 15% 5% 9% 5% 3 4 3 4 5% 36%	2472
	21st to end	Night	7% 14% 5% 10% 6% 5% 3 4 5% 6% 33%	1980
March	1st to 10th	Night	6% 16% 4 9% 5% 4 5% 3 5% 6% 36%	5166
	11th to 20th	Night	5% 11% 4 7% 4 4 6% 4 6% 8% 41%	5000
	21st to end	Night	6% 11% 4 8% 5% 5% 5% 4 6% 8% 38%	5489
April	1st to 10th	Night	8% 11% 3 6% 5% 4 4 3 5% 6% 43%	2132
	11th to 20th	Night	7% 10% 4 9% 5% 4 4 3 6% 5% 43%	1781
	21st to end	Night	8% 8% 3 6% 4 4 5% 5% 5% 5% 48%	1800
May	1st to 10th	Night	7% 10% 2 6% 4 4 4 3 4 6% 50%	4100
	11th to 20th	Night	7% 6% 3 6% 4 4 5% 5% 6% 7% 47%	4074
	21st to end	Night	6% 4 1 4 4 3 4 3 6% 7% 57%	4272
June	1st to 10th	Night	6% 5% 2 5% 4 3 5% 4 7% 9% 49%	1477
	11th to 20th	Night	8% 4 2 5% 3 3 4 3 5% 6% 58%	1400
	21st to end	Night	3 2 1 4 3 2 3 2 5% 6% 69%	1400
July	1st to 10th	Night	2 2 1 3 3 3 4 2 4 6% 71%	3517
	11th to 20th	Night	1 1 1 2 2 3 4 3 6% 6% 72%	3683
	21st to end	Night	1 1 1 2 3 3 3 4 5% 8% 68%	4472
August	1st to 10th	Night	2 1 1 3 3 3 4 4 7% 8% 63%	4033
	11th to 20th	Night	1 2 1 3 4 4 4 3 6% 7% 65%	4051
	21st to end	Night	3 3 1 4 3 3 4 3 4 5% 65%	4509
September	1st to 10th	Night	3 3 1 3 2 3 3 3 4 6% 70%	2105
	11th to 20th	Night	5% 4 1 4 3 3 4 3 5% 7% 61%	2200
	21st to end	Night	8% 4 2 4 2 3 3 3 4 4 65%	2200
October	1st to 10th	Night	5% 3 1 3 2 2 2 2 4 5% 70%	3744
	11th to 20th	Night	9% 6% 2 6% 4 3 3 3 4 5% 55%	3898
	21st to end	Night	6% 9% 3 5% 4 4 5% 3 6% 8% 48%	4430
November	1st to 10th	Night	11% 10% 3 5% 4 4 4 3 5% 7% 43%	2665
	11th to 20th	Night	10% 10% 4 6% 4 5% 4 4 5% 7% 39%	2756
	21st to end	Night	7% 12% 5% 8% 5% 5% 4 4 5% 7% 38%	2940
December	1st to 10th	Night	7% 10% 3 9% 4 3 3 3 4 4 49%	4710
	11th to 20th	Night	10% 16% 5% 10% 5% 4 4 3 5% 7% 31%	5389
	21st to end	Night	11% 16% 6% 11% 5% 5% 4 4 5% 6% 26%	7552

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	61% 6% 14% 15% 3	3719
	11th to 20th	Day	59% 6% 13% 15% 4 3	3808
	21st to end	Day	47% 7% 11% 22% 11% 1	4510
February	1st to 10th	Day	58% 8% 12% 17% 4 1	1800
	11th to 20th	Day	55% 7% 16% 16% 5% 1	1819
	21st to end	Day	53% 6% 16% 17% 8% 1	1650
March	1st to 10th	Day	50% 5% 12% 23% 6% 4	4727
	11th to 20th	Day	41% 5% 10% 33% 12%	5000
	21st to end	Day	54% 7% 17% 19% 4	5486
April	1st to 10th	Day	46% 6% 15% 18% 13% 3	2261
	11th to 20th	Day	41% 5% 10% 24% 18% 2	2570
	21st to end	Day	41% 5% 13% 24% 16% 1	2600
May	1st to 10th	Day	33% 3 11% 25% 22% 5%	5880
	11th to 20th	Day	33% 5% 9% 26% 23% 4	5844
	21st to end	Day	26% 5% 9% 29% 27% 5%	6608
June	1st to 10th	Day	29% 6% 13% 29% 20% 3	2918
	11th to 20th	Day	27% 4 11% 23% 24% 11%	3000
	21st to end	Day	15% 3 6% 21% 37% 19%	3000
July	1st to 10th	Day	12% 2 4 11% 26% 46%	6355
	11th to 20th	Day	13% 3 3 8% 28% 46%	6201
	21st to end	Day	15% 3 3 10% 33% 36%	6217
August	1st to 10th	Day	21% 4 4 14% 30% 28%	4208
	11th to 20th	Day	15% 3 4 17% 39% 23%	4197
	21st to end	Day	13% 3 4 20% 31% 29%	4663
September	1st to 10th	Day	17% 3 8% 16% 32% 24%	2289
	11th to 20th	Day	19% 4 10% 25% 28% 14%	2200
	21st to end	Day	22% 4 8% 23% 33% 10%	2200
October	1st to 10th	Day	22% 4 6% 18% 34% 16%	3450
	11th to 20th	Day	27% 3 9% 35% 20% 5%	3250
	21st to end	Day	35% 4 15% 30% 16% 1	3369
November	1st to 10th	Day	44% 5% 14% 23% 12% 1	1854
	11th to 20th	Day	42% 7% 19% 23% 7% 2	1839
	21st to end	Day	45% 5% 18% 21% 9% 2	1680
December	1st to 10th	Day	36% 6% 21% 32% 3 2	2700
	11th to 20th	Day	59% 7% 13% 18% 2	3028
	21st to end	Day	58% 5% 16% 15% 5%	3687
January	1st to 10th	Night	59% 6% 12% 19% 4	6446
	11th to 20th	Night	59% 5% 13% 18% 3 2	6273
	21st to end	Night	44% 8% 12% 22% 13% 1	6468
February	1st to 10th	Night	55% 8% 15% 16% 6%	2600
	11th to 20th	Night	50% 6% 15% 19% 10% 1	2473
	21st to end	Night	51% 6% 13% 20% 8% 2	1980
March	1st to 10th	Night	46% 5% 12% 22% 11% 4	5166
	11th to 20th	Night	37% 6% 13% 27% 17% 1	5000
	21st to end	Night	41% 7% 17% 25% 9% 1	5489
April	1st to 10th	Night	41% 5% 13% 21% 16% 4	2132
	11th to 20th	Night	41% 6% 12% 21% 18% 2	1781
	21st to end	Night	36% 5% 12% 24% 22% 1	1800
May	1st to 10th	Night	33% 4 11% 24% 23% 6%	4097
	11th to 20th	Night	32% 5% 9% 23% 26% 5%	4075
	21st to end	Night	24% 5% 9% 25% 31% 7%	4272
June	1st to 10th	Night	29% 6% 13% 23% 24% 5%	1477
	11th to 20th	Night	26% 5% 10% 20% 27% 13%	1400
	21st to end	Night	16% 3 5% 15% 34% 27%	1400
July	1st to 10th	Night	16% 3 3 10% 21% 48%	3477
	11th to 20th	Night	12% 3 2 6% 24% 53%	3635
	21st to end	Night	14% 3 3 9% 33% 39%	4344
August	1st to 10th	Night	16% 4 4 12% 25% 39%	2928
	11th to 20th	Night	21% 2 4 13% 35% 25%	2928
	21st to end	Night	15% 3 4 15% 32% 32%	3245
September	1st to 10th	Night	16% 3 7% 13% 28% 32%	2105
	11th to 20th	Night	23% 4 6% 21% 28% 18%	2200
	21st to end	Night	23% 3 6% 23% 33% 13%	2200
October	1st to 10th	Night	18% 3 7% 17% 37% 19%	3744
	11th to 20th	Night	32% 3 7% 30% 21% 8%	3898
	21st to end	Night	33% 5% 11% 30% 18% 2	4430
November	1st to 10th	Night	40% 5% 13% 23% 17% 2	2665
	11th to 20th	Night	42% 6% 16% 24% 10% 1	2756
	21st to end	Night	45% 5% 16% 23% 9% 2	2940
December	1st to 10th	Night	38% 5% 18% 33% 5% 1	4710
	11th to 20th	Night	53% 6% 18% 20% 3	5390
	21st to end	Night	57% 5% 15% 16% 7%	7552

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	27% 16% 23% 20% 13% 1	220
	11th to 20th	Day	16% 11% 32% 22% 15% 3	239
	21st to end	Day	18% 12% 30% 28% 11% 1	330
February	1st to 10th	Day	26% 19% 29% 20% 5%	300
	11th to 20th	Day	21% 21% 28% 22% 7% 1	355
	21st to end	Day	18% 21% 33% 20% 8% 1	414
March	1st to 10th	Day	21% 18% 32% 22% 6% 1	500
	11th to 20th	Day	14% 19% 31% 25% 11% 1	500
	21st to end	Day	20% 21% 32% 21% 5%	550
April	1st to 10th	Day	22% 19% 25% 24% 9% 1	500
	11th to 20th	Day	20% 23% 31% 16% 10% 1	492
	21st to end	Day	16% 19% 29% 24% 9% 2	500
May	1st to 10th	Day	10% 19% 31% 25% 13% 2	503
	11th to 20th	Day	16% 16% 27% 24% 14% 3	528
	21st to end	Day	15% 9% 24% 27% 18% 7%	653
June	1st to 10th	Day	7% 10% 25% 29% 23% 5%	730
	11th to 20th	Day	12% 12% 27% 31% 15% 3	730
	21st to end	Day	4 7% 26% 33% 24% 5%	730
July	1st to 10th	Day	2 6% 23% 38% 24% 5%	578
	11th to 20th	Day	2 6% 32% 39% 17% 3	524
	21st to end	Day	3 4 22% 39% 26% 6%	575
August	1st to 10th	Day	7% 6% 28% 33% 22% 5%	527
	11th to 20th	Day	3 6% 28% 35% 22% 6%	517
	21st to end	Day	5% 8% 22% 33% 26% 7%	583
September	1st to 10th	Day	4 7% 23% 30% 27% 10%	530
	11th to 20th	Day	6% 10% 27% 28% 22% 7%	530
	21st to end	Day	8% 9% 21% 33% 20% 8%	530
October	1st to 10th	Day	13% 11% 24% 25% 20% 8%	445
	11th to 20th	Day	12% 17% 20% 21% 22% 8%	330
	21st to end	Day	15% 15% 23% 33% 10% 3	363
November	1st to 10th	Day	18% 17% 26% 23% 13% 4	330
	11th to 20th	Day	17% 12% 33% 25% 12% 3	330
	21st to end	Day	16% 10% 29% 28% 14% 2	330
December	1st to 10th	Day	24% 8% 24% 28% 12% 4	330
	11th to 20th	Day	27% 10% 30% 23% 10%	311
	21st to end	Day	29% 12% 28% 17% 11% 2	242
January	1st to 10th	Night	21% 8% 26% 31% 13% 1	840
	11th to 20th	Night	21% 9% 23% 31% 14% 3	824
	21st to end	Night	21% 6% 22% 34% 15% 2	880
February	1st to 10th	Night	22% 11% 28% 29% 9% 1	800
	11th to 20th	Night	19% 8% 30% 33% 9% 2	784
	21st to end	Night	14% 12% 29% 32% 11% 2	660
March	1st to 10th	Night	14% 10% 31% 34% 10% 1	800
	11th to 20th	Night	11% 9% 29% 36% 14% 1	800
	21st to end	Night	19% 9% 27% 35% 9% 1	880
April	1st to 10th	Night	15% 11% 26% 32% 14% 1	782
	11th to 20th	Night	15% 10% 32% 33% 9% 1	593
	21st to end	Night	12% 9% 26% 36% 16% 2	600
May	1st to 10th	Night	11% 10% 21% 39% 17% 2	600
	11th to 20th	Night	10% 7% 22% 36% 22% 3	591
	21st to end	Night	14% 8% 18% 36% 21% 4	650
June	1st to 10th	Night	8% 6% 18% 40% 25% 3	477
	11th to 20th	Night	9% 6% 27% 41% 16% 1	400
	21st to end	Night	4 2 17% 45% 27% 5%	400
July	1st to 10th	Night	3 1 13% 48% 31% 4	390
	11th to 20th	Night	1 2 20% 49% 27% 1	405
	21st to end	Night	3 1 12% 48% 33% 4	657
August	1st to 10th	Night	4 2 16% 49% 27% 2	597
	11th to 20th	Night	4 2 14% 45% 31% 3	594
	21st to end	Night	4 3 17% 46% 26% 4	660
September	1st to 10th	Night	5% 3 17% 43% 27% 4	745
	11th to 20th	Night	7% 3 19% 41% 24% 6%	800
	21st to end	Night	10% 4 17% 38% 24% 7%	800
October	1st to 10th	Night	12% 4 22% 38% 22% 2	800
	11th to 20th	Night	12% 8% 20% 35% 22% 3	800
	21st to end	Night	10% 9% 24% 40% 15% 3	880
November	1st to 10th	Night	17% 9% 23% 35% 14% 3	820
	11th to 20th	Night	16% 9% 27% 34% 12% 1	866
	21st to end	Night	15% 9% 24% 35% 14% 2	1050
December	1st to 10th	Night	19% 9% 25% 35% 10% 1	1050
	11th to 20th	Night	23% 10% 28% 28% 10% 1	1050
	21st to end	Night	27% 11% 29% 25% 8% 1	1123

Page generated at 2026-01-13 23:14:28. Version ac07

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