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 2025-04-11.

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	8% 9% 3 7% 4 4 4 3 5% 6% 48%	117253
	Night	9% 11% 3 7% 4 4 4 3 5% 6% 44%	119866
Transparency	Day	37% 4 10% 21% 18% 10%	116999
	Night	42% 4 12% 21% 14% 7%	119708
Seeing	Day	12% 9% 23% 29% 20% 6%	15826
	Night	15% 5% 20% 40% 18% 2	25590

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	12% 25% 9% 11% 4 4 4 3 3 4 21%	3437
	11th to 20th	Day	10% 13% 6% 15% 8% 5% 4 2 4 4 30%	3750
	21st to end	Day	12% 18% 5% 10% 4 3 3 2 3 3 38%	4510
February	1st to 10th	Day	15% 17% 6% 11% 5% 4 4 4 4 5% 25%	1800
	11th to 20th	Day	13% 17% 5% 11% 6% 4 4 3 5% 5% 26%	1755
	21st to end	Day	9% 16% 6% 11% 6% 4 4 3 5% 6% 29%	1645
March	1st to 10th	Day	8% 15% 4 9% 5% 5% 4 3 6% 6% 35%	4772
	11th to 20th	Day	8% 14% 4 8% 4 4 4 3 4 4 43%	5000
	21st to end	Day	7% 14% 4 11% 6% 5% 6% 5% 7% 7% 28%	5486
April	1st to 10th	Day	11% 12% 4 7% 5% 4 4 5% 6% 7% 36%	2277
	11th to 20th	Day	8% 10% 3 7% 6% 4 4 4 5% 7% 42%	2439
	21st to end	Day	9% 10% 3 7% 5% 4 4 4 6% 8% 40%	2470
May	1st to 10th	Day	11% 10% 3 6% 5% 4 4 4 5% 8% 42%	4110
	11th to 20th	Day	4 5% 2 5% 4 4 5% 3 5% 9% 54%	4089
	21st to end	Day	8% 7% 3 7% 4 4 4 4 5% 7% 45%	4825
June	1st to 10th	Day	8% 4 2 6% 5% 4 5% 5% 7% 9% 45%	2791
	11th to 20th	Day	10% 5% 2 5% 3 4 4 3 5% 8% 50%	2850
	21st to end	Day	2 2 1 3 3 3 4 3 5% 7% 68%	2850
July	1st to 10th	Day	1 1 1 2 2 2 3 3 4 6% 75%	4740
	11th to 20th	Day	1 2 1 3 2 3 3 3 5% 7% 70%	4433
	21st to end	Day	2 2 1 3 3 3 3 3 5% 7% 67%	4454
August	1st to 10th	Day	3 4 2 4 3 3 4 4 6% 8% 58%	4092
	11th to 20th	Day	3 2 1 3 2 2 3 3 5% 8% 70%	4028
	21st to end	Day	2 3 1 3 3 3 3 3 4 5% 70%	4521
September	1st to 10th	Day	5% 3 1 2 3 3 3 2 4 5% 69%	2218
	11th to 20th	Day	7% 4 2 4 3 4 4 3 5% 6% 60%	2090
	21st to end	Day	7% 4 1 3 2 3 2 2 4 7% 63%	2090
October	1st to 10th	Day	7% 4 2 4 3 3 3 2 3 4 66%	3298
	11th to 20th	Day	6% 5% 2 4 3 3 4 2 3 5% 63%	3150
	21st to end	Day	9% 10% 3 7% 4 4 4 3 5% 6% 44%	3290
November	1st to 10th	Day	14% 10% 4 6% 4 4 4 3 4 6% 41%	1764
	11th to 20th	Day	13% 10% 3 8% 5% 4 4 3 5% 6% 38%	1640
	21st to end	Day	11% 15% 4 8% 4 4 4 3 4 5% 39%	1600
December	1st to 10th	Day	8% 11% 4 10% 4 2 2 2 3 4 49%	2620
	11th to 20th	Day	15% 21% 7% 13% 5% 4 4 3 4 4 20%	2871
	21st to end	Day	14% 17% 5% 11% 4 5% 5% 4 4 6% 25%	3498
January	1st to 10th	Night	11% 17% 6% 16% 5% 4 4 3 4 6% 24%	6536
	11th to 20th	Night	14% 20% 5% 14% 7% 4 4 2 3 4 24%	6211
	21st to end	Night	13% 18% 4 8% 3 3 3 2 3 5% 40%	6468
February	1st to 10th	Night	17% 17% 4 10% 5% 4 3 3 4 5% 26%	2600
	11th to 20th	Night	15% 18% 5% 9% 4 3 4 3 4 5% 30%	2532
	21st to end	Night	10% 16% 5% 13% 5% 4 5% 3 5% 5% 28%	1981
March	1st to 10th	Night	8% 15% 5% 9% 6% 4 4 3 4 5% 37%	5122
	11th to 20th	Night	8% 11% 3 7% 4 4 4 3 5% 7% 44%	5000
	21st to end	Night	8% 11% 4 7% 5% 5% 5% 5% 6% 9% 34%	5489
April	1st to 10th	Night	10% 13% 3 8% 5% 4 4 4 6% 7% 38%	2119
	11th to 20th	Night	10% 9% 2 7% 4 4 5% 5% 6% 7% 40%	1695
	21st to end	Night	9% 8% 2 6% 5% 4 4 4 6% 6% 46%	1710
May	1st to 10th	Night	8% 11% 3 7% 4 4 4 4 5% 7% 43%	2860
	11th to 20th	Night	4 4 2 6% 4 5% 5% 4 6% 7% 53%	2812
	21st to end	Night	9% 7% 2 6% 5% 4 5% 4 7% 8% 43%	2762
June	1st to 10th	Night	8% 5% 2 4 5% 4 5% 5% 8% 8% 46%	1384
	11th to 20th	Night	9% 5% 2 5% 3 4 5% 3 5% 7% 52%	1330
	21st to end	Night	2 2 2 3 2 2 4 3 5% 7% 67%	1330
July	1st to 10th	Night	2 2 1 2 3 3 2 3 5% 6% 71%	2220
	11th to 20th	Night	1 1 1 2 3 3 5% 3 6% 8% 68%	2521
	21st to end	Night	2 2 1 3 2 4 5% 4 5% 9% 64%	3109
August	1st to 10th	Night	3 2 1 4 4 3 4 4 6% 8% 60%	2847
	11th to 20th	Night	1 1 1 4 3 4 4 4 4 7% 65%	2811
	21st to end	Night	3 3 1 4 2 2 2 3 4 5% 71%	3146
September	1st to 10th	Night	5% 3 1 3 3 3 3 3 4 5% 67%	1958
	11th to 20th	Night	6% 4 1 4 3 4 3 3 5% 6% 60%	2090
	21st to end	Night	8% 4 1 3 2 2 2 3 4 6% 63%	2090
October	1st to 10th	Night	5% 4 2 4 2 2 2 2 3 4 70%	3676
	11th to 20th	Night	11% 6% 2 4 3 3 3 3 5% 5% 55%	3778
	21st to end	Night	8% 8% 3 8% 4 4 5% 4 5% 7% 44%	4267
November	1st to 10th	Night	14% 9% 2 6% 4 3 4 3 5% 6% 43%	2535
	11th to 20th	Night	13% 12% 3 6% 4 4 4 4 5% 7% 38%	2738
	21st to end	Night	10% 13% 5% 7% 5% 4 4 3 4 5% 40%	2800
December	1st to 10th	Night	9% 11% 4 8% 5% 3 3 2 3 4 46%	4570
	11th to 20th	Night	14% 21% 5% 10% 4 4 4 3 4 6% 25%	5311
	21st to end	Night	15% 18% 5% 10% 5% 4 4 3 4 5% 26%	7458

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 10% 14% 3	3437
	11th to 20th	Day	59% 4 16% 10% 8% 3	3750
	21st to end	Day	53% 4 10% 21% 10% 2	4510
February	1st to 10th	Day	62% 6% 12% 16% 4 1	1800
	11th to 20th	Day	58% 5% 14% 17% 5% 1	1764
	21st to end	Day	53% 8% 13% 18% 7% 1	1645
March	1st to 10th	Day	48% 4 15% 21% 9% 2	4772
	11th to 20th	Day	44% 4 10% 30% 11% 1	5000
	21st to end	Day	55% 5% 15% 20% 4	5486
April	1st to 10th	Day	45% 6% 15% 20% 13% 1	2277
	11th to 20th	Day	40% 5% 12% 27% 14% 2	2442
	21st to end	Day	41% 5% 11% 29% 14% 1	2470
May	1st to 10th	Day	40% 5% 6% 26% 18% 4	4110
	11th to 20th	Day	26% 5% 7% 32% 21% 9%	4092
	21st to end	Day	37% 4 9% 31% 17% 2	4825
June	1st to 10th	Day	34% 6% 14% 30% 17% 1	2791
	11th to 20th	Day	31% 4 10% 22% 22% 11%	2850
	21st to end	Day	17% 2 6% 24% 32% 20%	2850
July	1st to 10th	Day	11% 3 3 11% 34% 39%	4666
	11th to 20th	Day	15% 3 2 10% 25% 44%	4356
	21st to end	Day	17% 3 3 14% 34% 29%	4314
August	1st to 10th	Day	24% 3 4 16% 30% 23%	4078
	11th to 20th	Day	15% 3 4 21% 38% 20%	4067
	21st to end	Day	17% 3 4 21% 29% 27%	4520
September	1st to 10th	Day	18% 3 6% 17% 33% 22%	2218
	11th to 20th	Day	25% 3 8% 25% 27% 12%	2090
	21st to end	Day	23% 3 8% 29% 27% 10%	2090
October	1st to 10th	Day	24% 3 7% 21% 38% 7%	3298
	11th to 20th	Day	27% 2 11% 36% 18% 6%	3150
	21st to end	Day	40% 3 15% 26% 15% 1	3290
November	1st to 10th	Day	46% 4 17% 22% 11% 1	1764
	11th to 20th	Day	46% 6% 18% 22% 6% 2	1640
	21st to end	Day	48% 5% 19% 21% 8% 1	1600
December	1st to 10th	Day	40% 5% 25% 25% 4 1	2620
	11th to 20th	Day	67% 5% 13% 13% 2	2869
	21st to end	Day	61% 5% 14% 15% 5%	3498
January	1st to 10th	Night	62% 4 9% 19% 5%	6536
	11th to 20th	Night	65% 5% 12% 12% 5% 2	6211
	21st to end	Night	50% 4 13% 21% 9% 3	6468
February	1st to 10th	Night	60% 5% 14% 16% 5% 1	2600
	11th to 20th	Night	56% 4 14% 19% 6% 1	2533
	21st to end	Night	56% 5% 14% 16% 7% 1	1981
March	1st to 10th	Night	49% 4 12% 22% 9% 4	5122
	11th to 20th	Night	40% 4 13% 30% 12% 1	5000
	21st to end	Night	46% 6% 17% 25% 5%	5489
April	1st to 10th	Night	44% 6% 14% 22% 12% 2	2119
	11th to 20th	Night	41% 6% 12% 25% 14% 2	1695
	21st to end	Night	37% 5% 12% 28% 17%	1710
May	1st to 10th	Night	38% 7% 8% 27% 18% 2	2860
	11th to 20th	Night	26% 6% 9% 31% 22% 7%	2813
	21st to end	Night	36% 5% 9% 28% 20% 2	2762
June	1st to 10th	Night	31% 8% 14% 24% 21% 2	1384
	11th to 20th	Night	31% 5% 7% 22% 24% 11%	1330
	21st to end	Night	15% 4 7% 21% 29% 24%	1330
July	1st to 10th	Night	15% 3 4 12% 23% 43%	2185
	11th to 20th	Night	14% 2 2 11% 25% 45%	2475
	21st to end	Night	17% 4 4 16% 28% 31%	3011
August	1st to 10th	Night	21% 3 4 13% 32% 27%	2838
	11th to 20th	Night	20% 3 4 24% 29% 22%	2838
	21st to end	Night	17% 2 5% 19% 28% 29%	3146
September	1st to 10th	Night	19% 4 4 14% 33% 26%	1958
	11th to 20th	Night	24% 4 8% 23% 23% 17%	2090
	21st to end	Night	23% 3 6% 24% 33% 11%	2090
October	1st to 10th	Night	20% 2 7% 20% 37% 13%	3676
	11th to 20th	Night	32% 3 7% 34% 17% 7%	3778
	21st to end	Night	39% 4 13% 26% 18% 1	4267
November	1st to 10th	Night	41% 5% 16% 25% 12% 1	2535
	11th to 20th	Night	46% 5% 16% 25% 6% 2	2738
	21st to end	Night	47% 4 19% 20% 9% 1	2800
December	1st to 10th	Night	43% 4 24% 24% 4 1	4570
	11th to 20th	Night	61% 4 20% 13% 1	5312
	21st to end	Night	60% 4 13% 15% 7%	7458

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	24% 9% 17% 22% 24% 6%	200
	11th to 20th	Day	21% 4 17% 33% 18% 7%	223
	21st to end	Day	23% 5% 18% 31% 20% 3	330
February	1st to 10th	Day	26% 10% 28% 24% 10% 2	300
	11th to 20th	Day	21% 7% 29% 29% 12% 2	300
	21st to end	Day	18% 13% 26% 30% 11% 2	409
March	1st to 10th	Day	15% 15% 26% 33% 10% 2	500
	11th to 20th	Day	13% 12% 28% 28% 17% 2	500
	21st to end	Day	16% 17% 31% 26% 9% 1	550
April	1st to 10th	Day	17% 16% 25% 27% 13% 2	500
	11th to 20th	Day	14% 21% 30% 24% 11% 1	453
	21st to end	Day	15% 13% 25% 27% 15% 4	460
May	1st to 10th	Day	14% 13% 26% 25% 17% 5%	463
	11th to 20th	Day	11% 12% 25% 28% 18% 6%	493
	21st to end	Day	16% 7% 21% 26% 22% 8%	734
June	1st to 10th	Day	9% 10% 22% 28% 24% 7%	680
	11th to 20th	Day	13% 13% 25% 29% 17% 3	680
	21st to end	Day	4 6% 22% 37% 25% 5%	680
July	1st to 10th	Day	4 4 24% 37% 25% 7%	671
	11th to 20th	Day	3 6% 24% 40% 25% 3	503
	21st to end	Day	3 5% 21% 34% 27% 11%	531
August	1st to 10th	Day	6% 5% 22% 30% 31% 7%	487
	11th to 20th	Day	4 5% 19% 28% 32% 12%	477
	21st to end	Day	6% 8% 21% 29% 24% 12%	539
September	1st to 10th	Day	5% 5% 22% 29% 29% 11%	490
	11th to 20th	Day	9% 8% 23% 27% 24% 8%	490
	21st to end	Day	9% 8% 19% 28% 26% 10%	490
October	1st to 10th	Day	10% 5% 18% 29% 28% 9%	376
	11th to 20th	Day	11% 10% 20% 21% 22% 16%	300
	21st to end	Day	17% 12% 21% 29% 18% 3	330
November	1st to 10th	Day	21% 8% 23% 27% 13% 8%	300
	11th to 20th	Day	14% 9% 26% 34% 15% 3	300
	21st to end	Day	18% 7% 21% 34% 19% 2	300
December	1st to 10th	Day	21% 6% 20% 28% 18% 7%	300
	11th to 20th	Day	34% 4 18% 27% 17% 1	267
	21st to end	Day	25% 9% 15% 27% 18% 6%	220
January	1st to 10th	Night	23% 5% 15% 39% 18% 1	900
	11th to 20th	Night	24% 5% 18% 32% 18% 3	800
	21st to end	Night	22% 3 18% 41% 15% 2	880
February	1st to 10th	Night	26% 5% 22% 35% 11% 1	800
	11th to 20th	Night	22% 4 23% 37% 12% 2	784
	21st to end	Night	16% 7% 23% 39% 12% 2	660
March	1st to 10th	Night	17% 7% 21% 42% 13% 1	800
	11th to 20th	Night	15% 6% 25% 38% 16% 1	800
	21st to end	Night	16% 7% 25% 37% 13% 1	880
April	1st to 10th	Night	15% 7% 24% 39% 14% 1	740
	11th to 20th	Night	16% 7% 29% 37% 11% 1	565
	21st to end	Night	12% 5% 25% 39% 17% 1	570
May	1st to 10th	Night	9% 9% 27% 37% 18% 1	570
	11th to 20th	Night	9% 7% 23% 36% 23% 1	561
	21st to end	Night	13% 5% 22% 38% 19% 2	617
June	1st to 10th	Night	9% 6% 16% 42% 25% 3	434
	11th to 20th	Night	12% 3 27% 40% 17% 1	380
	21st to end	Night	3 2 16% 52% 25% 2	380
July	1st to 10th	Night	3 1 16% 49% 30% 2	370
	11th to 20th	Night	2 14% 63% 21%	375
	21st to end	Night	3 1 15% 48% 30% 2	624
August	1st to 10th	Night	5% 4 16% 47% 28% 1	567
	11th to 20th	Night	2 2 14% 50% 29% 2	564
	21st to end	Night	5% 2 19% 44% 28% 2	627
September	1st to 10th	Night	5% 2 16% 46% 27% 4	648
	11th to 20th	Night	7% 3 16% 40% 30% 5%	760
	21st to end	Night	10% 3 14% 40% 27% 6%	760
October	1st to 10th	Night	11% 4 16% 44% 23% 1	760
	11th to 20th	Night	14% 4 18% 39% 23% 3	760
	21st to end	Night	14% 6% 19% 42% 16% 4	836
November	1st to 10th	Night	18% 4 20% 38% 18% 1	780
	11th to 20th	Night	18% 6% 23% 39% 13% 1	938
	21st to end	Night	16% 5% 21% 38% 18% 2	1000
December	1st to 10th	Night	20% 5% 19% 40% 13% 2	1000
	11th to 20th	Night	25% 5% 17% 40% 12% 1	1000
	21st to end	Night	27% 6% 19% 34% 12% 1	1100

Page generated at 2025-04-08 07:17:29. Version ac07

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