Salmon Arm
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Salmon Arm clear sky chart from 2005-11-06 to 2024-04-10.

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	11% 10% 4 9% 7% 4 6% 6% 6% 7% 29%	82698
	Night	13% 13% 5% 9% 8% 4 5% 5% 5% 6% 26%	86054
Transparency	Day	52% 7% 14% 18% 7% 1	82410
	Night	57% 7% 13% 15% 7% 1	85922
Seeing	Day	16% 11% 24% 28% 17% 4	14764
	Night	21% 7% 20% 32% 18% 2	23429

By Month

Percentage Cloud Cover NW (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	16% 19% 7% 15% 9% 5% 5% 4 4 5% 11%	2137
	11th to 20th	Day	12% 17% 7% 8% 9% 5% 6% 5% 5% 8% 18%	2497
	21st to end	Day	11% 19% 10% 16% 9% 4 6% 6% 5% 5% 10%	2794
February	1st to 10th	Day	14% 18% 7% 12% 8% 3 5% 4 5% 5% 18%	1522
	11th to 20th	Day	11% 13% 4 10% 8% 3 6% 6% 6% 7% 25%	1665
	21st to end	Day	11% 12% 6% 13% 9% 5% 7% 8% 6% 6% 19%	1547
March	1st to 10th	Day	7% 13% 6% 13% 10% 5% 7% 6% 7% 7% 20%	3138
	11th to 20th	Day	7% 8% 3 7% 6% 4 6% 6% 7% 8% 37%	3295
	21st to end	Day	9% 12% 4 9% 8% 5% 7% 7% 6% 8% 25%	4149
April	1st to 10th	Day	11% 13% 6% 10% 9% 4 7% 5% 5% 8% 21%	2270
	11th to 20th	Day	11% 11% 5% 10% 9% 5% 6% 6% 7% 6% 26%	2175
	21st to end	Day	11% 9% 5% 10% 8% 5% 6% 7% 5% 8% 25%	2474
May	1st to 10th	Day	12% 9% 5% 9% 7% 4 6% 6% 5% 7% 29%	2520
	11th to 20th	Day	11% 7% 3 7% 8% 4 6% 6% 7% 9% 32%	2477
	21st to end	Day	17% 8% 3 8% 7% 4 6% 5% 6% 7% 30%	2834
June	1st to 10th	Day	16% 9% 4 8% 7% 4 7% 6% 6% 7% 26%	2784
	11th to 20th	Day	17% 9% 4 8% 9% 5% 8% 6% 6% 7% 22%	2880
	21st to end	Day	11% 8% 3 7% 7% 4 5% 5% 6% 7% 37%	2880
July	1st to 10th	Day	9% 5% 3 5% 6% 4 5% 5% 6% 7% 45%	2854
	11th to 20th	Day	6% 4 2 4 5% 4 5% 6% 7% 8% 47%	2606
	21st to end	Day	5% 3 2 4 3 3 4 4 6% 7% 59%	2741
August	1st to 10th	Day	5% 3 2 5% 5% 4 6% 5% 5% 7% 52%	2507
	11th to 20th	Day	5% 3 2 4 5% 3 5% 5% 7% 7% 54%	2475
	21st to end	Day	9% 6% 2 6% 5% 4 6% 6% 7% 9% 40%	2440
September	1st to 10th	Day	8% 5% 3 6% 5% 3 5% 5% 6% 7% 47%	2160
	11th to 20th	Day	12% 7% 3 6% 7% 5% 5% 5% 6% 7% 38%	2134
	21st to end	Day	13% 8% 4 8% 7% 4 5% 6% 7% 7% 31%	1972
October	1st to 10th	Day	13% 9% 4 8% 7% 4 6% 5% 5% 6% 33%	1800
	11th to 20th	Day	15% 10% 5% 9% 7% 3 6% 5% 7% 7% 27%	1724
	21st to end	Day	20% 13% 4 7% 7% 3 4 4 5% 6% 27%	1782
November	1st to 10th	Day	19% 16% 5% 10% 7% 4 6% 6% 5% 6% 17%	1571
	11th to 20th	Day	17% 14% 6% 9% 8% 5% 5% 6% 6% 6% 18%	1508
	21st to end	Day	16% 17% 6% 11% 11% 5% 6% 5% 5% 4 13%	1330
December	1st to 10th	Day	16% 15% 6% 12% 9% 6% 9% 5% 4 4 15%	1330
	11th to 20th	Day	17% 19% 8% 15% 9% 5% 6% 5% 4 4 8%	1636
	21st to end	Day	14% 16% 7% 12% 12% 7% 7% 5% 5% 4 11%	2090
January	1st to 10th	Night	15% 24% 8% 13% 9% 5% 5% 4 4 4 8%	4824
	11th to 20th	Night	12% 15% 8% 13% 10% 4 6% 4 5% 8% 15%	4384
	21st to end	Night	17% 20% 8% 16% 10% 5% 5% 4 4 3 9%	4862
February	1st to 10th	Night	15% 20% 6% 10% 8% 4 5% 5% 5% 4 18%	2656
	11th to 20th	Night	12% 15% 6% 10% 7% 4 4 4 6% 6% 26%	2402
	21st to end	Night	9% 16% 6% 10% 9% 5% 6% 5% 5% 7% 22%	1906
March	1st to 10th	Night	10% 12% 4 9% 7% 5% 6% 6% 7% 8% 26%	3736
	11th to 20th	Night	8% 9% 4 6% 6% 4 5% 5% 6% 7% 41%	3680
	21st to end	Night	9% 12% 4 8% 8% 4 6% 5% 7% 7% 29%	3503
April	1st to 10th	Night	11% 11% 5% 8% 7% 4 6% 6% 7% 7% 28%	1900
	11th to 20th	Night	11% 12% 4 9% 7% 5% 7% 8% 6% 6% 26%	1736
	21st to end	Night	10% 11% 4 8% 6% 3 6% 5% 7% 8% 31%	1486
May	1st to 10th	Night	11% 9% 5% 8% 7% 5% 5% 5% 6% 6% 33%	1440
	11th to 20th	Night	10% 6% 3 9% 7% 4 6% 5% 6% 10% 35%	1416
	21st to end	Night	15% 8% 3 7% 6% 4 5% 6% 6% 9% 32%	1441
June	1st to 10th	Night	17% 7% 4 8% 7% 4 5% 6% 6% 6% 31%	1172
	11th to 20th	Night	15% 8% 4 6% 9% 6% 6% 6% 8% 8% 24%	1080
	21st to end	Night	8% 6% 3 6% 7% 5% 6% 6% 6% 10% 36%	1080
July	1st to 10th	Night	10% 6% 3 4 5% 3 4 6% 7% 7% 46%	1103
	11th to 20th	Night	6% 4 2 5% 4 2 5% 5% 7% 8% 52%	1354
	21st to end	Night	7% 2 2 3 3 2 4 4 6% 7% 60%	1576
August	1st to 10th	Night	4 3 1 4 4 3 5% 5% 5% 9% 58%	1432
	11th to 20th	Night	4 4 1 3 4 2 4 4 5% 10% 59%	1424
	21st to end	Night	6% 4 1 5% 7% 4 7% 5% 6% 8% 45%	1912
September	1st to 10th	Night	8% 4 2 5% 5% 3 5% 5% 5% 6% 50%	1800
	11th to 20th	Night	12% 7% 2 6% 5% 2 4 4 5% 7% 45%	1826
	21st to end	Night	14% 8% 3 6% 5% 4 4 4 5% 6% 41%	1984
October	1st to 10th	Night	13% 7% 2 6% 5% 3 5% 5% 6% 8% 41%	2160
	11th to 20th	Night	16% 10% 3 8% 6% 4 5% 5% 5% 6% 34%	2235
	21st to end	Night	16% 10% 4 8% 7% 4 6% 5% 5% 7% 28%	2574
November	1st to 10th	Night	23% 13% 6% 10% 7% 4 6% 6% 5% 5% 18%	2504
	11th to 20th	Night	18% 15% 6% 9% 7% 4 5% 5% 5% 5% 21%	2660
	21st to end	Night	17% 18% 8% 9% 9% 4 6% 5% 4 5% 15%	2840
December	1st to 10th	Night	15% 15% 6% 11% 8% 5% 6% 5% 5% 7% 17%	2850
	11th to 20th	Night	17% 20% 8% 16% 9% 4 5% 4 4 4 9%	3550
	21st to end	Night	13% 16% 7% 13% 13% 5% 7% 5% 5% 5% 11%	5566

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	78% 9% 7% 6% 1	2137
	11th to 20th	Day	65% 8% 13% 8% 3 3	2521
	21st to end	Day	78% 8% 8% 5% 1	2794
February	1st to 10th	Day	69% 8% 10% 9% 4	1522
	11th to 20th	Day	58% 10% 15% 12% 5%	1674
	21st to end	Day	62% 8% 14% 12% 3 1	1547
March	1st to 10th	Day	60% 9% 11% 16% 4 1	3138
	11th to 20th	Day	41% 7% 23% 26% 3	3295
	21st to end	Day	55% 7% 16% 16% 5%	4149
April	1st to 10th	Day	58% 10% 12% 15% 4	2270
	11th to 20th	Day	54% 7% 14% 18% 6% 1	2175
	21st to end	Day	54% 7% 14% 17% 7%	2474
May	1st to 10th	Day	51% 6% 17% 17% 9%	2520
	11th to 20th	Day	44% 8% 16% 24% 8% 1	2480
	21st to end	Day	51% 6% 15% 19% 8% 1	2835
June	1st to 10th	Day	53% 7% 13% 16% 9% 3	2784
	11th to 20th	Day	57% 7% 13% 17% 5% 1	2880
	21st to end	Day	43% 6% 16% 21% 11% 2	2880
July	1st to 10th	Day	35% 6% 15% 24% 17% 4	2776
	11th to 20th	Day	30% 8% 16% 27% 16% 3	2526
	21st to end	Day	21% 5% 14% 32% 24% 3	2589
August	1st to 10th	Day	28% 7% 17% 27% 19% 2	2490
	11th to 20th	Day	27% 5% 18% 31% 17% 3	2475
	21st to end	Day	37% 7% 17% 28% 10% 1	2440
September	1st to 10th	Day	35% 7% 17% 30% 10% 2	2160
	11th to 20th	Day	44% 6% 16% 22% 11% 1	2134
	21st to end	Day	50% 9% 18% 15% 7% 1	1972
October	1st to 10th	Day	51% 7% 17% 21% 4	1800
	11th to 20th	Day	56% 7% 17% 17% 3	1724
	21st to end	Day	58% 9% 17% 13% 3	1782
November	1st to 10th	Day	70% 8% 11% 8% 3	1571
	11th to 20th	Day	64% 12% 12% 9% 2 1	1508
	21st to end	Day	75% 7% 11% 6% 1	1330
December	1st to 10th	Day	72% 8% 11% 8% 1	1330
	11th to 20th	Day	80% 8% 6% 4 1	1638
	21st to end	Day	70% 9% 11% 9% 1	2090
January	1st to 10th	Night	81% 6% 7% 5% 1	4824
	11th to 20th	Night	68% 8% 11% 7% 3 3	4422
	21st to end	Night	81% 6% 8% 4 1	4862
February	1st to 10th	Night	72% 6% 10% 7% 4 1	2656
	11th to 20th	Night	61% 7% 13% 13% 5% 1	2404
	21st to end	Night	60% 7% 15% 12% 6%	1906
March	1st to 10th	Night	54% 9% 12% 18% 7%	3736
	11th to 20th	Night	40% 7% 24% 24% 4	3681
	21st to end	Night	52% 7% 13% 19% 9%	3503
April	1st to 10th	Night	53% 10% 15% 16% 6%	1900
	11th to 20th	Night	55% 8% 13% 17% 7% 1	1736
	21st to end	Night	49% 7% 15% 21% 8% 1	1486
May	1st to 10th	Night	47% 8% 16% 19% 10% 1	1440
	11th to 20th	Night	43% 6% 17% 24% 9% 1	1416
	21st to end	Night	47% 6% 15% 22% 10%	1441
June	1st to 10th	Night	51% 7% 10% 20% 9% 3	1172
	11th to 20th	Night	53% 9% 13% 20% 6%	1080
	21st to end	Night	40% 9% 17% 20% 12% 2	1080
July	1st to 10th	Night	35% 6% 12% 25% 16% 5%	1072
	11th to 20th	Night	29% 7% 13% 32% 18% 2	1311
	21st to end	Night	21% 6% 12% 29% 27% 5%	1488
August	1st to 10th	Night	23% 6% 16% 26% 24% 4	1424
	11th to 20th	Night	21% 5% 16% 33% 22% 3	1424
	21st to end	Night	32% 7% 16% 28% 15% 2	1912
September	1st to 10th	Night	33% 7% 15% 29% 15% 2	1800
	11th to 20th	Night	38% 7% 12% 25% 16% 2	1826
	21st to end	Night	45% 7% 16% 21% 10% 1	1984
October	1st to 10th	Night	42% 9% 17% 24% 7%	2160
	11th to 20th	Night	52% 7% 15% 19% 6%	2235
	21st to end	Night	57% 7% 17% 15% 4	2574
November	1st to 10th	Night	70% 8% 10% 8% 3	2504
	11th to 20th	Night	66% 10% 11% 9% 4	2660
	21st to end	Night	72% 7% 13% 6% 3	2840
December	1st to 10th	Night	68% 8% 13% 9% 3	2850
	11th to 20th	Night	82% 6% 7% 4 1	3547
	21st to end	Night	72% 9% 11% 6% 2	5566

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	22% 12% 22% 26% 12% 6%	180
	11th to 20th	Day	27% 9% 24% 19% 13% 7%	180
	21st to end	Day	25% 8% 31% 23% 11% 2	198
February	1st to 10th	Day	25% 19% 29% 21% 5% 1	182
	11th to 20th	Day	16% 13% 27% 30% 12% 2	365
	21st to end	Day	15% 9% 34% 27% 13% 3	371
March	1st to 10th	Day	18% 19% 26% 22% 12% 2	460
	11th to 20th	Day	19% 15% 24% 23% 17% 2	460
	21st to end	Day	21% 16% 24% 22% 15% 2	506
April	1st to 10th	Day	22% 18% 26% 20% 12% 1	457
	11th to 20th	Day	18% 19% 25% 23% 11% 4	412
	21st to end	Day	15% 17% 27% 25% 13% 3	420
May	1st to 10th	Day	15% 15% 25% 31% 12% 2	423
	11th to 20th	Day	13% 12% 21% 29% 21% 5%	448
	21st to end	Day	17% 9% 20% 31% 19% 4	596
June	1st to 10th	Day	20% 12% 24% 28% 15% 1	714
	11th to 20th	Day	18% 11% 24% 31% 15% 1	810
	21st to end	Day	12% 9% 25% 28% 24% 3	810
July	1st to 10th	Day	13% 6% 20% 32% 25% 4	771
	11th to 20th	Day	6% 10% 25% 32% 22% 5%	525
	21st to end	Day	5% 6% 20% 37% 25% 8%	487
August	1st to 10th	Day	6% 6% 21% 32% 25% 11%	447
	11th to 20th	Day	8% 5% 21% 34% 23% 9%	437
	21st to end	Day	11% 9% 22% 32% 18% 8%	495
September	1st to 10th	Day	14% 9% 23% 33% 17% 5%	450
	11th to 20th	Day	14% 8% 26% 26% 23% 4	450
	21st to end	Day	17% 12% 26% 26% 16% 4	450
October	1st to 10th	Day	18% 10% 22% 28% 17% 5%	450
	11th to 20th	Day	19% 12% 25% 22% 19% 3	374
	21st to end	Day	28% 10% 25% 23% 14% 1	297
November	1st to 10th	Day	24% 10% 28% 21% 15% 1	221
	11th to 20th	Day	27% 13% 26% 18% 14% 3	180
	21st to end	Day	26% 11% 20% 27% 11% 5%	180
December	1st to 10th	Day	22% 7% 26% 25% 15% 6%	180
	11th to 20th	Day	19% 15% 35% 17% 9% 5%	180
	21st to end	Day	27% 8% 18% 38% 7% 2	198
January	1st to 10th	Night	34% 11% 21% 22% 10% 2	909
	11th to 20th	Night	27% 8% 22% 28% 13% 1	760
	21st to end	Night	24% 8% 24% 29% 13% 2	836
February	1st to 10th	Night	29% 9% 21% 28% 14% 1	760
	11th to 20th	Night	22% 9% 20% 33% 15% 1	744
	21st to end	Night	19% 9% 20% 31% 19% 3	628
March	1st to 10th	Night	23% 9% 22% 28% 17% 2	760
	11th to 20th	Night	19% 9% 25% 29% 17% 1	760
	21st to end	Night	17% 6% 27% 31% 16% 2	836
April	1st to 10th	Night	19% 11% 19% 31% 19% 2	760
	11th to 20th	Night	18% 8% 24% 35% 14% 1	668
	21st to end	Night	17% 8% 24% 37% 14%	406
May	1st to 10th	Night	12% 8% 21% 39% 19%	360
	11th to 20th	Night	12% 5% 19% 43% 21% 1	354
	21st to end	Night	18% 4 18% 34% 25% 1	389
June	1st to 10th	Night	17% 8% 18% 41% 15% 1	360
	11th to 20th	Night	17% 8% 16% 39% 21% 1	360
	21st to end	Night	12% 5% 16% 39% 26% 3	360
July	1st to 10th	Night	12% 3 14% 37% 33% 1	350
	11th to 20th	Night	7% 4 20% 40% 28% 2	348
	21st to end	Night	9% 2 9% 41% 38% 2	394
August	1st to 10th	Night	6% 2 11% 33% 45% 3	358
	11th to 20th	Night	7% 1 10% 41% 38% 3	356
	21st to end	Night	9% 4 11% 44% 30% 2	724
September	1st to 10th	Night	12% 3 14% 40% 29% 3	720
	11th to 20th	Night	15% 5% 13% 29% 33% 6%	720
	21st to end	Night	20% 4 18% 35% 21% 3	720
October	1st to 10th	Night	16% 4 18% 34% 26% 3	720
	11th to 20th	Night	21% 7% 19% 32% 20% 2	720
	21st to end	Night	25% 7% 22% 31% 13% 3	792
November	1st to 10th	Night	33% 7% 21% 31% 8%	740
	11th to 20th	Night	29% 10% 23% 25% 11% 2	760
	21st to end	Night	29% 8% 21% 27% 12% 3	940
December	1st to 10th	Night	26% 8% 20% 32% 13% 2	950
	11th to 20th	Night	30% 8% 22% 30% 9% 1	963
	21st to end	Night	32% 7% 22% 29% 9% 1	1144

Page generated at 2024-04-07 06:28:16. Version ac07

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