Rexburg Nature Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rexburg Nature Park clear sky chart from 2005-11-06 to 2026-08-15.

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	7% 8% 3 6% 4 4 4 3 5% 6% 50%	152599
	Night	8% 10% 3 7% 4 4 4 3 5% 6% 45%	146746
Transparency	Day	35% 4 9% 22% 20% 10%	147303
	Night	40% 4 11% 21% 16% 8%	143048
Seeing	Day	12% 9% 23% 29% 20% 6%	17725
	Night	15% 5% 20% 40% 18% 2	27234

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	13% 26% 8% 12% 4 4 4 3 3 4 20%	4466
	11th to 20th	Day	7% 11% 5% 12% 7% 4 3 2 3 4 42%	4892
	21st to end	Day	9% 16% 5% 10% 4 3 3 3 4 4 38%	5844
February	1st to 10th	Day	14% 17% 5% 11% 5% 4 4 4 4 5% 26%	1890
	11th to 20th	Day	13% 16% 5% 12% 6% 4 4 3 5% 5% 26%	1845
	21st to end	Day	10% 15% 6% 10% 6% 4 4 3 5% 6% 31%	1725
March	1st to 10th	Day	8% 15% 4 9% 5% 5% 4 3 6% 6% 34%	4877
	11th to 20th	Day	8% 13% 4 8% 4 4 4 3 4 4 43%	5110
	21st to end	Day	7% 13% 4 11% 6% 5% 6% 5% 7% 7% 28%	5607
April	1st to 10th	Day	10% 11% 4 7% 5% 4 4 5% 6% 7% 37%	2391
	11th to 20th	Day	8% 10% 3 7% 5% 4 4 4 5% 7% 43%	2697
	21st to end	Day	9% 10% 3 7% 5% 4 5% 4 6% 8% 39%	2730
May	1st to 10th	Day	6% 7% 2 4 3 3 3 3 5% 8% 56%	7626
	11th to 20th	Day	5% 6% 3 7% 4 5% 6% 4 6% 8% 46%	7628
	21st to end	Day	8% 6% 2 6% 4 4 4 3 6% 8% 51%	9026
June	1st to 10th	Day	8% 4 2 5% 5% 4 5% 5% 7% 8% 47%	3085
	11th to 20th	Day	9% 5% 2 5% 3 4 4 3 5% 8% 52%	3150
	21st to end	Day	3 3 1 3 3 3 3 3 5% 7% 66%	3150
July	1st to 10th	Day	1 2 1 3 2 3 4 3 5% 7% 69%	8819
	11th to 20th	Day	1 2 1 3 3 3 3 3 5% 7% 70%	8248
	21st to end	Day	2 2 1 4 3 4 4 4 6% 7% 63%	8304
August	1st to 10th	Day	3 4 2 4 3 3 4 4 6% 8% 61%	5909
	11th to 20th	Day	2 2 1 2 2 3 3 3 5% 8% 70%	5851
	21st to end	Day	4 4 2 4 3 3 3 3 4 5% 65%	6468
September	1st to 10th	Day	5% 3 1 2 3 3 3 2 4 5% 69%	2335
	11th to 20th	Day	7% 4 2 4 3 4 4 3 5% 6% 60%	2200
	21st to end	Day	7% 5% 1 3 2 3 2 2 4 7% 63%	2200
October	1st to 10th	Day	7% 4 2 4 3 3 2 2 3 4 66%	3402
	11th to 20th	Day	6% 5% 2 4 3 3 4 2 3 5% 62%	3250
	21st to end	Day	8% 10% 3 7% 4 4 4 3 5% 6% 45%	3395
November	1st to 10th	Day	14% 10% 4 6% 4 4 4 3 4 6% 41%	1854
	11th to 20th	Day	13% 10% 3 8% 5% 4 5% 3 5% 6% 37%	1722
	21st to end	Day	10% 15% 4 8% 4 4 4 3 4 5% 39%	1680
December	1st to 10th	Day	8% 11% 5% 10% 4 2 2 2 3 4 48%	2700
	11th to 20th	Day	15% 20% 7% 12% 5% 4 4 3 4 4 21%	2948
	21st to end	Day	14% 17% 5% 10% 4 5% 5% 4 4 6% 26%	3575
January	1st to 10th	Night	13% 19% 6% 16% 5% 5% 4 3 4 5% 21%	8468
	11th to 20th	Night	10% 15% 4 11% 6% 3 3 2 3 5% 37%	8072
	21st to end	Night	10% 15% 5% 9% 4 3 3 2 4 6% 39%	8370
February	1st to 10th	Night	16% 17% 4 10% 5% 4 3 3 5% 6% 27%	2730
	11th to 20th	Night	14% 18% 5% 10% 4 4 4 3 4 5% 30%	2662
	21st to end	Night	10% 16% 5% 13% 5% 4 5% 3 5% 6% 29%	2077
March	1st to 10th	Night	8% 15% 5% 9% 6% 4 4 3 4 5% 37%	5236
	11th to 20th	Night	8% 11% 3 7% 4 4 4 3 5% 7% 44%	5110
	21st to end	Night	8% 11% 4 8% 5% 5% 5% 5% 6% 9% 34%	5610
April	1st to 10th	Night	10% 13% 3 7% 5% 4 4 4 6% 7% 38%	2225
	11th to 20th	Night	10% 9% 2 7% 4 4 5% 5% 5% 7% 40%	1871
	21st to end	Night	9% 8% 2 6% 5% 4 4 4 6% 7% 45%	1890
May	1st to 10th	Night	6% 7% 2 6% 4 3 4 3 5% 7% 53%	5321
	11th to 20th	Night	5% 6% 2 6% 4 5% 5% 4 6% 8% 48%	5260
	21st to end	Night	8% 5% 2 5% 4 4 5% 4 7% 9% 48%	5181
June	1st to 10th	Night	8% 5% 2 5% 4 5% 5% 5% 8% 8% 46%	1530
	11th to 20th	Night	9% 4 1 5% 3 4 5% 3 5% 7% 54%	1470
	21st to end	Night	3 3 2 4 2 2 4 3 5% 7% 66%	1470
July	1st to 10th	Night	1 2 1 4 3 4 4 4 6% 8% 64%	4140
	11th to 20th	Night	1 1 1 2 3 3 4 4 6% 8% 67%	4707
	21st to end	Night	1 2 1 4 3 4 5% 4 6% 9% 61%	5805
August	1st to 10th	Night	3 2 2 4 3 3 4 4 6% 9% 61%	4123
	11th to 20th	Night	1 1 1 3 3 4 4 4 5% 7% 68%	4087
	21st to end	Night	7% 5% 2 5% 2 2 2 3 4 6% 61%	4509
September	1st to 10th	Night	4 3 1 3 3 3 3 3 4 5% 67%	2061
	11th to 20th	Night	6% 4 1 4 3 4 4 3 5% 6% 60%	2200
	21st to end	Night	8% 4 1 3 2 2 2 3 4 7% 63%	2200
October	1st to 10th	Night	6% 4 2 4 2 2 2 2 3 4 70%	3792
	11th to 20th	Night	11% 6% 2 4 3 3 3 3 5% 5% 54%	3898
	21st to end	Night	8% 8% 3 7% 4 4 5% 4 5% 7% 45%	4404
November	1st to 10th	Night	14% 9% 2 6% 4 3 4 3 5% 6% 43%	2665
	11th to 20th	Night	13% 12% 3 6% 4 4 4 4 6% 7% 37%	2875
	21st to end	Night	10% 13% 5% 7% 5% 4 4 3 4 6% 40%	2940
December	1st to 10th	Night	9% 11% 4 8% 5% 3 3 2 3 4 46%	4710
	11th to 20th	Night	14% 20% 5% 9% 4 4 4 3 4 6% 26%	5454
	21st to end	Night	15% 18% 5% 10% 5% 4 4 3 4 5% 27%	7623

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	68% 4 14% 11% 3	4467
	11th to 20th	Day	47% 4 22% 16% 9% 2	4892
	21st to end	Day	50% 4 13% 20% 11% 1	5844
February	1st to 10th	Day	61% 6% 12% 17% 4 1	1890
	11th to 20th	Day	59% 5% 14% 16% 5% 1	1854
	21st to end	Day	52% 8% 13% 19% 7% 1	1725
March	1st to 10th	Day	48% 4 15% 21% 9% 2	4877
	11th to 20th	Day	44% 3 10% 30% 11% 1	5110
	21st to end	Day	55% 5% 14% 21% 5%	5607
April	1st to 10th	Day	45% 6% 14% 22% 12% 1	2391
	11th to 20th	Day	40% 5% 11% 26% 15% 3	2700
	21st to end	Day	42% 5% 10% 28% 14% 1	2730
May	1st to 10th	Day	28% 4 7% 31% 26% 5%	7626
	11th to 20th	Day	35% 4 6% 23% 24% 8%	7631
	21st to end	Day	31% 3 8% 34% 22% 2	9027
June	1st to 10th	Day	33% 5% 12% 28% 19% 2	3085
	11th to 20th	Day	30% 4 9% 22% 24% 11%	3150
	21st to end	Day	18% 2 5% 24% 32% 18%	3150
July	1st to 10th	Day	15% 3 2 14% 31% 35%	8746
	11th to 20th	Day	15% 2 2 17% 29% 35%	8171
	21st to end	Day	20% 3 4 14% 35% 24%	8120
August	1st to 10th	Day	24% 2 4 16% 30% 24%	4338
	11th to 20th	Day	15% 3 4 20% 38% 19%	4250
	21st to end	Day	18% 3 4 21% 28% 27%	4663
September	1st to 10th	Day	18% 3 7% 18% 33% 22%	2335
	11th to 20th	Day	25% 3 8% 25% 27% 12%	2200
	21st to end	Day	23% 3 8% 28% 28% 10%	2200
October	1st to 10th	Day	24% 3 7% 21% 38% 7%	3402
	11th to 20th	Day	27% 2 10% 37% 18% 5%	3250
	21st to end	Day	40% 3 14% 27% 15% 1	3395
November	1st to 10th	Day	45% 4 18% 23% 10% 1	1854
	11th to 20th	Day	46% 6% 18% 22% 6% 2	1722
	21st to end	Day	47% 5% 19% 21% 8% 1	1680
December	1st to 10th	Day	41% 5% 24% 25% 3 1	2700
	11th to 20th	Day	66% 5% 14% 13% 2	2946
	21st to end	Day	60% 4 14% 15% 5%	3575
January	1st to 10th	Night	67% 4 9% 17% 4	8469
	11th to 20th	Night	51% 5% 22% 15% 6% 1	8072
	21st to end	Night	48% 4 15% 21% 8% 4	8370
February	1st to 10th	Night	58% 5% 15% 16% 5% 1	2730
	11th to 20th	Night	57% 4 14% 18% 6% 1	2663
	21st to end	Night	55% 5% 14% 17% 7% 1	2077
March	1st to 10th	Night	49% 4 12% 22% 9% 4	5236
	11th to 20th	Night	40% 4 13% 29% 12% 1	5110
	21st to end	Night	46% 6% 17% 25% 6%	5610
April	1st to 10th	Night	44% 6% 13% 23% 12% 2	2225
	11th to 20th	Night	41% 6% 12% 24% 16% 2	1871
	21st to end	Night	38% 5% 11% 27% 18%	1890
May	1st to 10th	Night	30% 5% 6% 26% 30% 3	5319
	11th to 20th	Night	31% 5% 7% 23% 25% 9%	5261
	21st to end	Night	31% 4 7% 26% 29% 2	5182
June	1st to 10th	Night	32% 7% 13% 23% 22% 3	1530
	11th to 20th	Night	30% 4 7% 22% 25% 12%	1470
	21st to end	Night	17% 4 6% 20% 29% 23%	1470
July	1st to 10th	Night	18% 3 3 13% 24% 39%	4105
	11th to 20th	Night	15% 3 3 14% 29% 36%	4661
	21st to end	Night	20% 3 4 17% 28% 28%	5677
August	1st to 10th	Night	21% 3 4 13% 31% 28%	3018
	11th to 20th	Night	20% 3 3 24% 29% 22%	2964
	21st to end	Night	18% 2 5% 19% 28% 29%	3245
September	1st to 10th	Night	20% 3 5% 14% 33% 25%	2061
	11th to 20th	Night	25% 4 8% 24% 24% 16%	2200
	21st to end	Night	23% 3 7% 23% 34% 11%	2200
October	1st to 10th	Night	20% 2 7% 21% 37% 13%	3792
	11th to 20th	Night	33% 3 7% 34% 17% 6%	3898
	21st to end	Night	38% 4 13% 27% 17% 1	4404
November	1st to 10th	Night	41% 5% 16% 26% 12% 1	2665
	11th to 20th	Night	46% 5% 17% 24% 6% 2	2875
	21st to end	Night	46% 4 19% 20% 9% 1	2940
December	1st to 10th	Night	44% 4 24% 23% 4 1	4710
	11th to 20th	Night	60% 4 20% 13% 2	5455
	21st to end	Night	60% 4 14% 15% 7%	7623

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	26% 9% 18% 20% 21% 5%	220
	11th to 20th	Day	20% 4 16% 34% 20% 7%	246
	21st to end	Day	22% 5% 17% 33% 21% 3	363
February	1st to 10th	Day	25% 10% 27% 24% 12% 3	330
	11th to 20th	Day	21% 7% 29% 28% 13% 2	330
	21st to end	Day	18% 14% 26% 30% 10% 2	441
March	1st to 10th	Day	17% 14% 26% 31% 10% 2	540
	11th to 20th	Day	14% 13% 28% 27% 16% 1	540
	21st to end	Day	15% 19% 30% 26% 9% 1	594
April	1st to 10th	Day	17% 16% 25% 27% 13% 2	540
	11th to 20th	Day	15% 20% 29% 23% 11% 1	532
	21st to end	Day	16% 14% 26% 27% 14% 4	540
May	1st to 10th	Day	13% 11% 25% 27% 18% 5%	543
	11th to 20th	Day	11% 14% 26% 27% 16% 6%	574
	21st to end	Day	15% 7% 20% 27% 23% 8%	844
June	1st to 10th	Day	9% 10% 23% 28% 23% 6%	780
	11th to 20th	Day	12% 13% 26% 29% 17% 3	780
	21st to end	Day	6% 7% 22% 36% 24% 5%	780
July	1st to 10th	Day	3 4 24% 38% 25% 6%	771
	11th to 20th	Day	2 6% 23% 39% 25% 4	585
	21st to end	Day	3 5% 21% 34% 26% 10%	619
August	1st to 10th	Day	5% 5% 24% 30% 31% 6%	567
	11th to 20th	Day	4 5% 21% 29% 30% 11%	534
	21st to end	Day	6% 7% 21% 30% 23% 12%	583
September	1st to 10th	Day	4 5% 21% 29% 29% 12%	530
	11th to 20th	Day	8% 8% 23% 29% 25% 8%	530
	21st to end	Day	9% 8% 19% 27% 26% 10%	530
October	1st to 10th	Day	10% 5% 19% 29% 27% 9%	410
	11th to 20th	Day	12% 11% 22% 22% 21% 14%	330
	21st to end	Day	16% 11% 20% 29% 20% 4	363
November	1st to 10th	Day	22% 8% 22% 27% 14% 8%	330
	11th to 20th	Day	14% 8% 26% 33% 15% 3	330
	21st to end	Day	18% 7% 21% 33% 19% 2	330
December	1st to 10th	Day	22% 7% 20% 28% 16% 7%	330
	11th to 20th	Day	33% 5% 19% 26% 17% 1	294
	21st to end	Day	26% 9% 15% 25% 19% 6%	242
January	1st to 10th	Night	23% 5% 16% 38% 17% 1	945
	11th to 20th	Night	23% 5% 18% 33% 18% 3	840
	21st to end	Night	21% 3 18% 42% 14% 2	924
February	1st to 10th	Night	25% 5% 22% 35% 12% 1	840
	11th to 20th	Night	22% 5% 23% 37% 11% 2	824
	21st to end	Night	16% 8% 23% 38% 12% 2	692
March	1st to 10th	Night	17% 7% 22% 41% 12% 1	840
	11th to 20th	Night	16% 6% 25% 37% 15% 1	840
	21st to end	Night	16% 8% 26% 37% 13% 1	924
April	1st to 10th	Night	15% 7% 24% 39% 14% 1	777
	11th to 20th	Night	16% 8% 29% 37% 10% 1	623
	21st to end	Night	12% 7% 26% 38% 16% 1	630
May	1st to 10th	Night	9% 10% 26% 37% 18% 1	630
	11th to 20th	Night	9% 9% 24% 36% 21% 1	621
	21st to end	Night	13% 5% 23% 38% 19% 2	683
June	1st to 10th	Night	9% 6% 17% 42% 24% 2	480
	11th to 20th	Night	11% 4 28% 42% 16%	420
	21st to end	Night	5% 2 17% 50% 24% 2	420
July	1st to 10th	Night	2 1 17% 51% 28% 2	410
	11th to 20th	Night	2 13% 64% 20%	416
	21st to end	Night	3 1 16% 49% 29% 1	690
August	1st to 10th	Night	4 4 17% 48% 25% 1	627
	11th to 20th	Night	3 2 15% 50% 28% 2	606
	21st to end	Night	6% 2 19% 44% 27% 2	660
September	1st to 10th	Night	5% 2 16% 46% 27% 4	682
	11th to 20th	Night	7% 3 15% 40% 30% 5%	800
	21st to end	Night	10% 3 14% 40% 28% 5%	800
October	1st to 10th	Night	11% 4 16% 45% 23% 1	800
	11th to 20th	Night	14% 5% 19% 38% 22% 3	800
	21st to end	Night	13% 6% 19% 43% 16% 3	880
November	1st to 10th	Night	17% 5% 20% 39% 18% 1	820
	11th to 20th	Night	18% 6% 23% 40% 13% 1	985
	21st to end	Night	16% 5% 21% 38% 18% 2	1050
December	1st to 10th	Night	21% 6% 19% 39% 13% 2	1050
	11th to 20th	Night	24% 6% 18% 39% 12% 1	1050
	21st to end	Night	27% 7% 20% 33% 12% 1	1155

Page generated at 2026-08-12 01:37:18. Version ac07

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