Your nature year
Mason City, Iowathrough the year
When do frost, green-up and fall color come to Mason City?
The town is about 1,108 feet above sea level. Leaves usually come out around Apr 14 and the first flowers around May 11.
Spring takes about 4 weeks to go from leaf to bloom. At the nearest NOAA station, Mason City, the average first fall frost is Oct 7 and the last spring frost Apr 29, which leaves Mason City some 161 growing days. Trempealeau Refuge, 104 miles from Mason City, is the nearest spring migration spot on this site, late April or early May (local timing). Minnesota Valley Refuge (117 mi) is the pick for wildflowers, Jun 1–Aug 31 (local timing). We follow 3 places within 150 miles of Mason City; the nearest lies 104 miles to the northeast.
Updated Sep 27. Sources: US Census Bureau, 2024 Gazetteer (places) ↗ (opens in a new tab), US Census Bureau, city and town population estimates, 2024 ↗ (opens in a new tab), NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal) ↗ (opens in a new tab)
Best this weekend nearby
- Mississippi River, Minneapolis–St. Paul · 122 mi · Fall foliage
Usually Sep 24–Oct 7
Sat Oct 3: Partly Sunny, 65°F · Sun Oct 4: Sunny, 63°F
No report yet
Places in their own usual window that weekend; reports are the latest official ones, forecasts from the National Weather Service.
Mason City's year at a glance
- Frost possible
- Frost-free, ~Apr 29 to ~Oct 7
- First leaf ~Apr 14
- First bloom ~May 11
- Today
Near Mason City right now
- First fall frost usually around Oct 7 · last spring frost around Apr 29NOAA 1991–2020 normals, Mason City (1.1 mi, 50% dates)~8 days
- Mississippi River, Minneapolis–St. Paul · 122 mi · usually Sep 24–Oct 7Fall foliage · in its window now
- Spring migration · Trempealeau Refuge · 104 miLocal timing: late April or early May~7 months
Mason City's nature year
- Spring migration · Trempealeau RefugeApr–May
- Apr: Spring green-upApr
- Apr: Last spring frostApr
- Wildflowers · Minnesota Valley RefugeJun–Aug
- Fall foliage · Mississippi River, Minneapolis–St. PaulNowSep–Oct
- Oct: First fall frostOct
Nearby, season by season
Fall foliage
- Mississippi River, Minneapolis–St. Paul · 122 miusually Sep 24–Oct 7
Spring migration
- Trempealeau Refuge · 104 miLocal timing: late April or early May~7 months
Wildflowers
- Minnesota Valley Refuge · 117 miLocal timing: Jun 1–Aug 31~8 months
Snow in Mason City
Snow usually becomes possible around Nov 12 (our calculation from NOAA's daily snow chances: the first day the chance of 0.1" or more of snow reaches 10%). NOAA's normals at Mason City Municipal Airport (6.4 mi away): 44 inches of snow in an average year, about 13.4 days with 1 inch or more.
NOAA's chance of at least 0.1 inch of snow on each date (one value per week, September to May), averaged over 1991–2020. A typical year, not a forecast.
Frost and green-up
Last spring frost
Apr 29
Average (50% date)
First fall frost
Oct 7
About 161 days without frost between
Spring green-up
Apr 14
First bloom around May 11
Frost: NOAA 1991–2020 climate normals at Mason City (1.1 mi from Mason City), the day a 32 °F night is as likely as not. Green-up: the USA-NPN Spring Index, 1991–2020 average at the town.
Questions people ask
When is the first frost in Mason City?
On average around Oct 7, and the last spring frost around Apr 29: about 161 days without frost between. These are NOAA's 1991–2020 normals at Mason City, 1.1 miles away (the day a 32 °F night is as likely as not).
When does spring green-up reach Mason City?
The USA-NPN Spring Index puts first leaf around Apr 14 and first bloom around May 11, on average for 1991–2020 at the town.
Where can I see fall foliage near Mason City?
Mississippi River, Minneapolis–St. Paul, 122 miles (usually Sep 24–Oct 7). Distances are straight-line.
Where can I see spring migration near Mason City?
Trempealeau Refuge, 104 miles (local timing: late April or early May). Distances are straight-line.
When does it start snowing in Mason City?
Snow usually becomes possible around Nov 12: our calculation from NOAA's daily snow chances: the first day the chance of 0.1" or more of snow reaches 10%, at Mason City Municipal Airport. An average year brings 44 inches (NOAA 1991–2020). A typical year, not a forecast.Sources: NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal snowfall) ↗ (opens in a new tab), NOAA NCEI U.S. Climate Normals 1991–2020 (daily snowfall probabilities) ↗ (opens in a new tab)
How we know
US Census Bureau, 2024 Gazetteer (places) (opens in a new tab) (Sep 27) · US Census Bureau, city and town population estimates, 2024 (opens in a new tab) (Sep 27) · NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal) (opens in a new tab) (Sep 27) · USA National Phenology Network, Spring Index 1991–2020 averages (opens in a new tab) (Sep 27)